EEVblog HVP70 Differential Probe

[EEVblog]

Looks sweet!

[JPortici]

.. Do i even have to say it?

Take it apart

[tautech]

Clips and grabber options ?

[EEVblog]

Clips and grabber options ?

Just the standard hooks. BYO isolated banana to whatever

[tautech]

Clips and grabber options ?

Just the standard hooks. BYO isolated banana to whatever

So shown are grabber hooks ?
Like scope probe hooks ?

They look pretty fine, what size mm wire will they grab ?

[alanb]

Is it available yet?
How much does it cost?

[EEVblog]

So shown are grabber hooks ?
Like scope probe hooks ?

Yes.

They look pretty fine, what size mm wire will they grab ?

Large stuff, they aren't fine. Maybe 1.5sqmm

[EEVblog]

Is it available yet?
How much does it cost?

A few weeks.
How much would you pay?

[capt bullshot]

How much would you pay?

I've taken apart and re-adjusted the attenuator compensation and CMRR of such a thing (apparently something in the input divider changed its behaviour over usage and time). Regarding what is inside, all commercially available probes of this kind are heavily overpriced IMO. I think it should be less than 180 Euros.

Does yours run on ext. power supply? (Batteries have a strong tendency to be maximum empty when needed most urgent)

[EEVblog]

I've taken apart and re-adjusted the attenuator compensation and CMRR of such a thing (apparently something in the input divider changed its behaviour over usage and time). Regarding what is inside, all commercially available probes of this kind are heavily overpriced IMO. I think it should be less than 180 Euros.

Market niche for you then, go for it.

Does yours run on ext. power supply? (Batteries have a strong tendency to be maximum empty when needed most urgent)

Yes, both external and batteries.

[tautech]

Hmmm, looks like similar specs to Sapphire. 

[BravoV]

Curious is that the old thru hole design ? or newer using smd ?

[djnz]

Neat!

[bitwelder]

Nice!

What certifications will it have?

[TheAmmoniacal]

Hmmm... $600 AUD? Stretch it down to 500?

[TheAmmoniacal]

Hmmm... $600 AUD? Stretch it down to 500?

Guess I was in the range: https://www.amazon.com/gp/aw/d/B06XHYMP7D/

$399 USD

EDIT: Dave made it unavailable, so he's still just dicking around with Amazon and probably still undecided on the price.

[BravoV]

Hmmm... $600 AUD? Stretch it down to 500?

Where did you get that number from ? 

[nctnico]

I like the Pintek ones better. You can stick a BNC to banana adapter in those and connect an isolated scope probe. 70MHz through flying leads is pushing your luck way too far.

[BravoV]

70MHz through flying leads is pushing your luck way too far.

I guess that for "young players" ... 

[joeqsmith]

Dang, I should have entered the giveaway when I fill out the questionnaire.   Looks nice. 

[amspire]

Pricing depends on who you want to sell to. If you are working with Mains and switching power supplies, these can be your best friend - worth every bit of $600 if it is good.

I would really love to see how this goes connected to the gate circuit in a high side mosfet in a switching supply. If you can actually see the gate waveform fairly accurately, that would be impressive. Any specs on common mode rejection ratio at various frequencies?

For selling to hobbyists, I think a US$100 price would sell 10 times more then US$200 and so it comes down to how much they cost to build. I know there is nothing like this on the market at these kind of prices, and the only reason to go there would be to sell in quantity and because you have managed to use economical components.

Definitely at $400, there would be a decent professional market. There are 25MHz probes with 1300V DC + peak AC for about US$230. They will not be as good, but they are an option if you are on a budget.

[capt bullshot]

I would really love to see how this goes connected to the gate circuit in a high side mosfet in a switching supply. If you can actually see the gate waveform fairly accurately, that would be impressive. Any specs on common mode rejection ratio at various frequencies?

The people here use these probes (Yokogawa brand labeled, 100MHz BW spec) to monitor gate drive signals on high side IGBTs, common mode is up to 800V and up to a some kV/us (well, it depends, can't go into details). And yes, they can see a gate drive signal.

There's also a downside: no one checks the probes for compensation and CMRR, not even when they get calibrated in a external cal lab :-(
It's perfectly possible to pull a probe out of the storage box with a fresh cal sticker on it and real bad compensation / CMRR. Some months ago, I volunteered an re-adjusted a bunch of them - again no one noticed the change.
The probe simply is used to measure and document the gate signals, no matter if they are misread by bad compensation or CMRR.

I really like these probes, even if I don't need the high safety ratings (other people here need that), but when it comes to real perfomance, it's better to have your own that has never been used by the power people and lab rats before - they simply do not take care of their equipment.

BTW, the probes I re-adjusted have standard SMT components (1206 planar resistors and caps) for the high voltage divider (several components in series). That's quite cheap ass style, yes it works as long as you don't treat them with high dV/dt rates and you don't have high voltage transients. The standard resistors and capacitors degrade slowly over time (and change their values) if you treat them this way (which is well within their safety ratings, no specs exceeded), leading to bad compensation and CMRR. Then one says, they are worth each dollar they cost - yes maybe in terms of safety they provide, but no, not in terms of performance and long time stability I do expect from such an expensive accessory.

[alanb]

Is it available yet?
How much does it cost?

A few weeks.
How much would you pay?

It would be for occasional hobby use, on that basis I wouldn't want to spend more than about £50.

[MrW0lf]

Quick teardown? 

[TheSteve]

Looks good, but you were supposed to announce it before I bought an Agilent N2891A(70 MHz 7 kV).

[EEVblog]

Is it available yet?
How much does it cost?

A few weeks.
How much would you pay?

It would be for occasional hobby use, on that basis I wouldn't want to spend more than about £50.

You'll have to make your own for that.

[technogeeky]

Is it available yet?
How much does it cost?

A few weeks.
How much would you pay?

It would be for occasional hobby use, on that basis I wouldn't want to spend more than about £50.

You'll have to make your own for that.

Dave:

I'm sure this will be a fine product. Do you know why these don't generally come with (shrouded, or not) banana jacks? Wouldn't it be nice to allow people to use whatever leads they prefer to use?

Is it not possible (or practical) to calibrate against varying leads? Could you just assume they are identical?

[EEVblog]

I'm sure this will be a fine product. Do you know why these don't generally come with (shrouded, or not) banana jacks? Wouldn't it be nice to allow people to use whatever leads they prefer to use?

It does come with shrouded banana jacks (plugs actually), just on the end of the leads. Make or buy your own adapters.

Is it not possible (or practical) to calibrate against varying leads? Could you just assume they are identical?

That's a unique system measurement issue.

[Dubbie]

I would pay up to $300usd

[Fsck]

Hmmm, looks like similar specs to Sapphire. 

that was my first impression too.

for the hobbyist market, 300$ is really a good spot. Lower is obviously better though. 250$ would really sweep the (really tiny) market of the others.

[amspire]

that was my first impression too.

for the hobbyist market, 300$ is really a good spot. Lower is obviously better though. 250$ would really sweep the (really tiny) market of the others.

You are right. When someone can come up with a decent $50 differential probe, the hobbyist will really star buying. $300 is the price of an 100MHz 1GS/sec digital oscilloscope  - I cannot see the majority being interested in a probe for the same price.

For professionals, I think they would easily pay $600 if it had a great CMRR, was very safe and unbreakable.

[EEVblog]

For professionals, I think they would easily pay $600 if it had a great CMRR, was very safe and unbreakable.

Pretty standard for these types of probes:

CMRR (typical)
-80dB @50Hz,
-60dB @20kHz
-50 dB @ 1MHz
-40 dB @ 10MHz

[amspire]

For professionals, I think they would easily pay $600 if it had a great CMRR, was very safe and unbreakable.

Pretty standard for these types of probes:

CMRR (typical)
-80dB @50Hz,
-60dB @20kHz
-50 dB @ 1MHz
-40 dB @ 10MHz

Not bad. Definitely competitive. The rating is for 700V differential and common mode, but it is tested at 1000V RMS for safety.

Even if it does not function at 1000V RMS, does the probe survive?

[neslekkim]

So with these, I can probe around everywhere without worrying about blowing my scope? (looking at vide #932)

would be nice if these would be not too expensive for hobbyists..  $200?, $250?

[amspire]

Yes. That is what they are for. Great for viewing a 5v signal in a switching inverter running on rectified mains. Might have 400V peak to peak common mode signals. Safe for the scope and the operator.

[gamalot]

Looks like Sapphire SI9010 (about 5200CNY on Taobao, 1485AUD on Trio, tax excl.)

[cheeseit]

Very interesting Dave. I'm hoping that you release a video explaining the various use cases for this probe and how to use it properly, and the likely gotchas involved. I know the basics but think that a relative high price for a hobbyist might be offset by some explanation and examples of why it's such a useful tool, and knowing how to use it without damaging either tool, scope, DUT or operator.

[HighVoltage]

Looks great from the picture.

If you can sell them for $ 200, you will probably sell a lot of them.

[TheAmmoniacal]

People act like Dave can put any price he wants on it.. He has to buy them from the manufacturer and have them sent to his office, then he needs a profit to make the sale worth it. He is already pushing it with the amount of profit which is worthwhile, I am sure..

[fcb]

Looking forward to the tear-down and explanation of why this isn't just a rebadged product?

[TheAmmoniacal]

Looking forward to the tear-down and explanation of why this isn't just a rebadged product?

I would be surprised if it wasn't a rebadge, what's wrong with that?

[EEVblog]

So with these, I can probe around everywhere without worrying about blowing my scope? (looking at vide #932)

Yes, that's exactly what they are for.

would be nice if these would be not too expensive for hobbyists..  $200?, $250?

You'll have to buy a cheapie on ebay to get that price.

[EEVblog]

Looking forward to the tear-down and explanation of why this isn't just a rebadged product?

It is just a rebadged product, but it's a new model no one else has yet AFAIK. Same as the BM235.

[EEVblog]

If you can sell them for $ 200, you will probably sell a lot of them.

I don't think people realise how much these probes currently sell for. You can't even buy a cheapie ebay or Aliexpress 25MHz job for $200, let alone a quality 70MHz one.

[nctnico]

If you can sell them for $ 200, you will probably sell a lot of them.

I don't think people realise how much these probes currently sell for. You can't even buy a cheapie ebay or Aliexpress 25MHz job for $200, let alone a quality 70MHz one.

Still I'd like to see them cheaper so there is no excuse for people to do measurements in a crazy unsafe way.

[Helix70]

Looks like Sapphire SI9010 (about 5200CNY on Taobao, 1485AUD on Trio, tax excl.)

Actually, more like a 70 Mhz version of the SI-9101, which is a 100Mhz -3db, 1/10 and 1/100 differential probe with +/-70V on 1:10, and are 975AUD on Trio, tax excl.

That one you quoted is 1:100 and 1:1000, and withstands higher voltages

[EEVblog]

Still I'd like to see them cheaper so there is no excuse for people to do measurements in a crazy unsafe way.

Of course. Sorry I can't make that magically happen.

[EEVblog]

I like the Pintek ones better.

They are clones of Sapphire:
http://www.sapphire.com.tw/notify.pdf

[Avacee]

Slightly off-topic - apologies if I should have started a new thread.

Do probe and oscilloscope db's add up?
I.e. a 70Mhz signal through this probe into a 70Mhz oscilloscope - would the displayed signal be 6db down?

[Pinkus]

looks like it is an OEM producing also for Keysight (see N2791A) or LeCroy (see picture attached check the same packaging, housing/rubber and layout of switches) (thoug both are 25 Mhz versions).

Teardown: http://bardagjy.com/?p=1664

[TheAmmoniacal]

The Teledyne LeCroy is 25 MHz and $495 on Digikey, do they have a 70 MHz version of this?

[madires]

I like the Pintek ones better.

They are clones of Sapphire:
http://www.sapphire.com.tw/notify.pdf

Pintek != Pintech or did I get that wrong?

[Pinkus]

The Teledyne LeCroy is 25 MHz and $495 on Digikey, do they have a 70 MHz version of this?

Yep, wrote that, but it seems I deleted this accidentally (I added it now again).
Of course these 25 Mhz products mentioned by me are internally not identical with an 70 Mhz model - I just spotted, that housing and packaging are identical. I did not see a 70 Mhz in this housing.... but I have not looked too much. Maybe it is an upcoming product.

[nctnico]

I like the Pintek ones better.

They are clones of Sapphire:
http://www.sapphire.com.tw/notify.pdf

No, Pintek is not Pintech. The ones from Pintek are completely different and have 0.75" / 19mm spaced banana sockets:

[mcinque]

Looks like Sapphire SI9010 (about 5200CNY on Taobao, 1485AUD on Trio, tax excl.)

you can find that design under various brands like Pico, Testec and others; probably they are all rebadge of the original (made by? Sapphire?).

[HighVoltage]

If you can sell them for $ 200, you will probably sell a lot of them.

I don't think people realise how much these probes currently sell for. You can't even buy a cheapie ebay or Aliexpress 25MHz job for $200, let alone a quality 70MHz one.

Oh, I overlooked the 70 MHZ
The 25 MHz Pintek sells in Germany for around Euro 250

Looking forward seeing a teardown and review of your EEVblog Differential Probe.

[saturation]

Looks like "Pintech"  have look alikes to both Pintek and Sapphire designs.

http://www.pintech.com.cn/prolist.asp?str=%B2%EE%B7%D6%CC%BD%B0%F4OEM&style=142&idtop=0

The Taiwanese Pintek and Sapphire have always been relatively expensive but they are workhorses, the design are fairly straightforward and ripe for cloning, and there are teardowns of both in the forum archives. 

[bitwelder]

I don't think people realise how much these probes currently sell for. You can't even buy a cheapie ebay or Aliexpress 25MHz job for $200, let alone a quality 70MHz one.

What are the expensive parts of a high voltage probe? (Or, if you open up one, how do you estimate its value?)

[Hideki]

What are the expensive parts of a high voltage probe? (Or, if you open up one, how do you estimate its value?)

The most expensive part is the manufacturer's profit margin. There are no particulary expensive parts inside. They are simply used to selling it at a high price and would like to continue doing so.

[mtdoc]

When I first saw this I thought it said HPV70.  I gasped and thought that's an unfortunate choice of model number since HPV has whole 'nother meaning in the medical world.

Be safe - Don't let your high voltage probe get HPV...

[TheAmmoniacal]

When I first saw this I thought it said HPV70.  I gasped and thought that's an unfortunate choice of model number since HPV has whole 'nother meaning in the medical world.

Be safe - Don't let your high voltage probe get HPV...

Better yet, there actually is an HPV 70 virus (type 70)

[Avacee]

I don't think people realise how much these probes currently sell for. You can't even buy a cheapie ebay or Aliexpress 25MHz job for $200, let alone a quality 70MHz one.

What are the expensive parts of a high voltage probe? (Or, if you open up one, how do you estimate its value?)

Dave's teardown of a Lecroy AP031 25MHz HV Differential probe. a.k.a Sapphire Instruments SI-9001
The components will only be a fractional cost of the design, testing, official validation, customer support, office space, staff wages, staff coffee fund, profit margin from limited sales demographic etc, etc .....

[TheAmmoniacal]

It definitely would be cool to see Dave try to design his own, see how cheap it's possible to go on a differential probe at these specifications. Although I suspect the testing/legalities would make it too expensive or complicated to sell?

[David Hess]

I've taken apart and re-adjusted the attenuator compensation and CMRR of such a thing (apparently something in the input divider changed its behaviour over usage and time).

There's also a downside: no one checks the probes for compensation and CMRR, not even when they get calibrated in a external cal lab :-(
It's perfectly possible to pull a probe out of the storage box with a fresh cal sticker on it and real bad compensation / CMRR. Some months ago, I volunteered an re-adjusted a bunch of them - again no one noticed the change.
The probe simply is used to measure and document the gate signals, no matter if they are misread by bad compensation or CMRR.

...

BTW, the probes I re-adjusted have standard SMT components (1206 planar resistors and caps) for the high voltage divider (several components in series). That's quite cheap ass style, yes it works as long as you don't treat them with high dV/dt rates and you don't have high voltage transients. The standard resistors and capacitors degrade slowly over time (and change their values) if you treat them this way (which is well within their safety ratings, no specs exceeded), leading to bad compensation and CMRR. Then one says, they are worth each dollar they cost - yes maybe in terms of safety they provide, but no, not in terms of performance and long time stability I do expect from such an expensive accessory.

If suitable components are used, then usually it is the printed circuit board material which changes (or starts out bad) screwing up the high impedance compensated dividers.  Tektronix called this "hook" and before qualifying standard fiberglass weave printed circuit board material, early on they used boards made from plastics like polysulfone (amber looking) for their high impedance attenuators and later a white board material that I have not identified yet.

Analog Devices mentions it briefly on page 10 of Analog Dialogue Volume 17, Number 2, 1983 and page 58 of chapter 9 of The Data Conversion Handbook 2005 but the best reference is still the Tektornix article "Getting Rid of Hook - The Hidden PC-Board Capacitance" in Electronics magazine October 12, 1978 which I have available through a bittorrent magnet link.  It is too large for Dave's forum unless I edit it and the scan is in bad enough shape already so I left it alone although I am pretty good at cleaning up old document scans.

I really like these probes, even if I don't need the high safety ratings (other people here need that), but when it comes to real perfomance, it's better to have your own that has never been used by the power people and lab rats before - they simply do not take care of their equipment.

Jim Williams had something to say about maladjusted probe compensation:

"The translation of this statement is to hide the probe when you are not using it.  If anyone wants to borrow it, look straight at them, shrug your shoulders and say you don't know where it is.  This is decidedly dishonest, but eminently practical.  Those finding this morally questionable may wish to re-examine their attitude after producing a day's worth of worthless data with a probe that was unknowingly readjusted." - page 12 of Linear Technology application note 49)

[mtdoc]

Jim Williams had something to say about maladjusted probe compensation:

"The translation of this statement is to hide the probe when you are not using it.  If anyone wants to borrow it, look straight at them, shrug your shoulders and say you don't know where it is.  This is decidedly dishonest, but eminently practical.  Those finding this morally questionable may wish to re-examine their attitude after producing a day's worth of worthless data with a probe that was unknowingly readjusted." - page 12 of Linear Technology application note 49)

He also was a fan of the Tektronix p6046 differential probe but commented on how tricky they were to trim properly after repair. They don't have the high voltage capability of Dave's probe but for someone looking for a budget differential probe, they can be found on eBay for < $100.

[BravoV]

He also was a fan of the Tektronix p6046 differential probe but commented on how tricky they were to trim properly after repair. They don't have the high voltage capability of Dave's probe but for someone looking for a budget differential probe, they can be found on eBay for < $100.

+1 , made this quote while ago when I was waiting to get that probe for years at cheap price.

Btw, I'm not sure these days you can get that P6046 at that price anymore.

[mtdoc]

He also was a fan of the Tektronix p6046 differential probe but commented on how tricky they were to trim properly after repair. They don't have the high voltage capability of Dave's probe but for someone looking for a budget differential probe, they can be found on eBay for < $100.

+1 , made this quote while ago when I was waiting to get that probe for years at cheap price.

Btw, I'm not sure these days you can get that P6046 at that price anymore.

I just checked. There's a few on eBay now for < $100.  This one looks good but is an auction. Opening bid $50.

If I didn't already have one....

[BravoV]

I just checked. There's a few on eBay now for < $100.  This one looks good but is an auction. Opening bid $50.

Interesting, lets see what the closing bid will be as I'm curious too.

If I didn't already have one....

Worst, I have two 

[EEVblog]

I don't think people realise how much these probes currently sell for. You can't even buy a cheapie ebay or Aliexpress 25MHz job for $200, let alone a quality 70MHz one.

What are the expensive parts of a high voltage probe? (Or, if you open up one, how do you estimate its value?)

The leading company in this field, Sapphire, just make diff probes and nothing else. It's their sole source of income, they have to pay for R&D staff etc. Development does not come cheap. 
It not just about the cost of the parts inside.

Sent from my D5833 using Tapatalk

[EEVblog]

There is so much speculation here.
Yes it is a rebadged Sapphire.
It is a new 70MHz model in the old 25MHz case.
No it is not available anywhere else yet that am aware of.
I will be able to sell a 70MHz model for the price of a 25MHz
I don't expect everyone to think it's good value, it's not hobbyist level pricing.

Sent from my D5833 using Tapatalk

[TheSteve]

Looks like my Agilent N2891A is a Sapphire SI-9010A - or at least a slightly customized version of it.

[EEVblog]

All the major scope makers rebadge the Sapphire, they have been the standard for 20+ years.

[nctnico]

I will be able to sell a 70MHz model for the price of a 25MHz
I don't expect everyone to think it's good value, it's not hobbyist level pricing.

Well you can't put a price tag on your own safety! IMHO it is one of those situations where you just have to bite the bullet. Come to think of it... I think the differential probes are among the most expensive probes I have (based on the price I paid for any particular probe).

[amspire]

I used my first probe like this around 1988. I seem to remember it cost about A$800 and the bandwidth might have been 20MHz. In all the time since then, good differential probes have never changed much in price, so there has to be something difficult in designing and making good, safe probes.

You would hope you are buying from a manufacturer the fully tests the probes at the full voltages, as you may have a scope worth thousands of dollars at stake, as well as your safety. And you definitely do not want to spend days following a glitch that turns out to be a probe problem.

Back then, we also had the BWD Powerscope
http://www.ebay.com.au/itm/BWD-880-POWERSCOPE-/121480140048?hash=item1c48c7d510:g:uisAAOSwzOxUWwa8
Which had 4 differential channels designed for safe HV use. Don't know if anyone makes anything like that now.

The one above is missing the 8 special shrouded HV probes, so it will be fun replacing them.

[TheSteve]

Having a good differential probe isn't just about personal safety, it is also about protecting the scope from a connection error etc. If you have a $2000.00(or easily more) scope the probe suddenly doesn't seem so expensive.

[mikeselectricstuff]

I used my first probe like this around 1988. I seem to remember it cost about A$800 and the bandwidth might have been 20MHz. In all the time since then, good differential probes have never changed much in price, so there has to be something difficult in designing and making good, safe probes.

More like just a big enough market for people to put much into R&D

[amspire]

I used my first probe like this around 1988. I seem to remember it cost about A$800 and the bandwidth might have been 20MHz. In all the time since then, good differential probes have never changed much in price, so there has to be something difficult in designing and making good, safe probes.

More like just a big enough market for people to put much into R&D

I don't know about that. If someone was selling good $50 differential probes, I think people would just buy them as a standard part of their scope kit. I just assume that it is hard to achieve a good safe $50 differential probe.

[Mechatrommer]

this is 70MHz unit allright, not 25MHz... just to be fair with other products brands fame and shame... when are we going to expect for dont turn it on, take it apart session of this thing? yet, a detailed specification is not yet know where to download...

[EEVblog]

He also was a fan of the Tektronix p6046 differential probe but commented on how tricky they were to trim properly after repair. They don't have the high voltage capability of Dave's probe but for someone looking for a budget differential probe, they can be found on eBay for < $100.

+1 , made this quote while ago when I was waiting to get that probe for years at cheap price.

Btw, I'm not sure these days you can get that P6046 at that price anymore.

I just checked. There's a few on eBay now for < $100.  This one looks good but is an auction. Opening bid $50.

That is not a high voltage probe, not the same thing.

[EEVblog]

I don't know about that. If someone was selling good $50 differential probes, I think people would just buy them as a standard part of their scope kit. I just assume that it is hard to achieve a good safe $50 differential probe.

$50 retail, very likely not easy.

[EEVblog]

I used my first probe like this around 1988. I seem to remember it cost about A$800 and the bandwidth might have been 20MHz. In all the time since then, good differential probes have never changed much in price, so there has to be something difficult in designing and making good, safe probes.

More like just a big enough market for people to put much into R&D

Likely.
I think most companies just reverse engineer the Sapphire and use that as their base circuit.

[mtdoc]

He also was a fan of the Tektronix p6046 differential probe but commented on how tricky they were to trim properly after repair. They don't have the high voltage capability of Dave's probe but for someone looking for a budget differential probe, they can be found on eBay for < $100.

+1 , made this quote while ago when I was waiting to get that probe for years at cheap price.

Btw, I'm not sure these days you can get that P6046 at that price anymore.

I just checked. There's a few on eBay now for < $100.  This one looks good but is an auction. Opening bid $50.

That is not a high voltage probe, not the same thing.

Yep, no doubt - and why I mentioned that in my post. Still a useful, low cost, low voltage differential probe.

[David Hess]

Yep, no doubt - and why I mentioned that in my post. Still a useful, low cost, low voltage differential probe.

The P6046 is very or even irreplaceably useful if you actually have an application which needs something like it.  This probe was Tektronix's longest lived product.

There is a big difference in performance between low voltage and high voltage differential probes.  The Sapphire and similar high voltage differential probes do not include a complete CMRR versus frequency or noise (or recovery time) specifications for good reason; they cannot compete with the P4046 in this respect or even the old Tektronix 7A13 and Preamble 1822 (bought by LeCroy) designs when they are used with the proper external probes.  Except for input voltage range, even an properly adjusted oscilloscope in add and invert mode can be competitive. (1)

On the other hand, they are perfectly suited for line side applications like off-line switching power supplies where a higher voltage range is required and are simpler to use and less expensive than a 7A13 or Preamble 1822.  And if capt bullshot's story about calibration is common, then most users do not understand or know how to accurately use them anyway.

As far as their seemingly high price, I suspect it is just a situation of what the limited market will bear and the design and validation is tricky for such a low volume product.

(1) It is a little eerie using an analog oscilloscope in add and invert mode while adjusting it for maximum CMRR.  You can *see* the displayed noise decrease when it is adjusted correctly.  The same goes for adjusting the external probes on a 7A13 or Preample 1822.  The movie opens on a fog shrouded hill; the fog clears as the audience yells, "Focus!"

[EEVblog]

Just discovered an embarrassing issue that will delay shipment of the fist batch.
#NotMyFault

[Jay_Diddy_B]

Hi,

Are the red and black leads, + plus and - minus mixed up? They are different than other sapphire probes.



Regards,

Jay_Diddy_B

[_Wim_]

Well you can't put a price tag on your own safety! IMHO it is one of those situations where you just have to bite the bullet. Come to think of it... I think the differential probes are among the most expensive probes I have (based on the price I paid for any particular probe).

For safety at a lower price tag you can also buy the Tektronix A6902B 2 channel isolator (http://exodus.poly.edu/~kurt/manuals/manuals/Tektronix/TEK%20A6902B%20Operator.pdf) for around 100$ at EBay. Not as high of a bandwidth as the differential probes discussed here (when taking into account the high frequency derating => max 3MHz for 500V, and max 20MHz to low voltages), but for sure a lot safer than floating the DUT or scope. CMRR is in the same league as more modern differential probes.

[amspire]

I have an old Hantek 60Mhz 2150 USB oscilloscope which I could run off a battery pack.

I am going to try out a USB isolator using the AD chip and see if I can make the Hantek run in a useful manner on USB 1.1. You can buy 1500V isolator boards on Ebay for about A$15. Also have some 100x 2500V 100MHz probes on order for about the same price. Don't have any projects planned for this - probably just trying to find a use for the Hantek scope.

http://www.ebay.com/itm/381860044223
http://www.ebay.com/itm/282303148790

The idea is to leave it floating. Not a replacement for a differential probe when there are huge slew rate, but fine for general checking of Mains potential circuits.

Even if the provided software does not work, there is a fair bit of Open source stuff that probably would work.

[_Wim_]

I have an old Hantek 60Mhz 2150 USB oscilloscope which I could run off a battery pack.

I am going to try out a USB isolator using the AD chip and see if I can make the Hantek run in a useful manner on USB 1.1. You can buy 1500V isolator boards on Ebay for about A$15. Also have some 100x 2500V 100MHz probes on order for about the same price. Don't have any projects planned for this - probably just trying to find a use for the Hantek scope.

http://www.ebay.com/itm/381860044223
http://www.ebay.com/itm/282303148790

The idea is to leave it floating. Not a replacement for a differential probe when there are huge slew rate, but fine for general checking of Mains potential circuits.

Even if the provided software does not work, there is a fair bit of Open source stuff that probably would work.

Floating a scope can be dangerous because scope housing could go to a high potential (scope was not designed to be used as floating).
For example with your proposal, when you probe with 1 input of the Hantek, the outside of the other BNC connectors can (will) go to a live voltage. Accidently touching one of these connectors poses a real danger. Also metal screw used for assembly of the housing could be dangerous. As the inputs of the Hantek are not isolated from each other, probing with 2 channels can cause dangerous short circuits.

I would also be weary to trust a chinse USB isolator (fake chips?) to protect me and my pc from high voltages. Imagen you pc becomes “live” and you want to operate your scope.

So I would recommend against your proposed approach. If it was this easy (cheap) to probe safely at high voltages, all scopes would add have this feature as standard…

[_Wim_]

Also the USB cable between Hantek and USB Isolator, and half of the USB isolator will be at high potential when probing around. USB cables are not designed for this.

[amspire]

Floating a scope can be dangerous because scope housing could go to a high potential (scope was not designed to be used as floating).
...

The case would definitely be high. I wouldn't dream of touching it if it was attached to a live HV circuit.

For example, if I ever work on developing mains switching supplies, I always now put the device under test behind a shield. I have seen enough explosively fragmented mosfets and diodes to know this is a good idea. The live USB scope would also be behind the shield.

It is not a great idea to be touching the probes of a differential probe when the circuit is live.

I would also be weary to trust a chinse USB isolator (fake chips?) to protect me and my pc from high voltages. Imagen you pc becomes “live” and you want to operate your scope.

I would test it. There are 3 parts across the PCB gap - an Optocoupler, a Capacitor and the IC. I would go to the full 1500V in my tests.  Might even try two isolators in series with the first one attached to a very heavily earthed powered hub on its output. That would be safe.

As I said, I don't have a use for this yet - just want to see if the idea works. May be I would use it more often to see differential voltages on low voltage circuits - such as monitoring the voltage across a current resistor in the positive line of a grounded low voltage power supply.

[bson]

What is the output impedance of this to feed a 1Mohm input at 70MHz?

Looks interesting though, if the price is right I'll definitely buy one to have on hand, even if I very rarely have an urge to go poking around in the mains side of supplies...  (Priced right would be, say, US$499 or less.)

[_Wim_]

Floating a scope can be dangerous because scope housing could go to a high potential (scope was not designed to be used as floating).
...

The case would definitely be high. I wouldn't dream of touching it if it was attached to a live HV circuit.

For example, if I ever work on developing mains switching supplies, I always now put the device under test behind a shield. I have seen enough explosively fragmented mosfets and diodes to know this is a good idea. The live USB scope would also be behind the shield.

It is not a great idea to be touching the probes of a differential probe when the circuit is live.

I would also be weary to trust a chinse USB isolator (fake chips?) to protect me and my pc from high voltages. Imagen you pc becomes “live” and you want to operate your scope.

I would test it. There are 3 parts across the PCB gap - an Optocoupler, a Capacitor and the IC. I would go to the full 1500V in my tests.  Might even try two isolators in series with the first one attached to a very heavily earthed powered hub on its output. That would be safe.

As I said, I don't have a use for this yet - just want to see if the idea works. May be I would use it more often to see differential voltages on low voltage circuits - such as monitoring the voltage across a current resistor in the positive line of a grounded low voltage power supply.

I just wanted to make this clear for beginners reading this that it is not intrinsically safe. Many beginners will not realize a live housing and could seriously harm themselves.
I fully agree with nctnico that you cannot put a price on safety, even (especially!) if you are a beginner/hobbyist. So when working on higher voltages, only use probes specifically designed for this purpose.  Because  I do understand that buying a couple of high voltage differential probes can be a big investment, I recommended the Tektronix isolator above with can be bought cheap. This is old technology (was probably quite expensive in its day), but safe and specifically designed for this purpose.

An even safer solution is NOT probing high voltages (mains) at all with a scope. Most info you need to know can be provided by a multimeter.

[David Hess]

What is the output impedance of this to feed a 1Mohm input at 70MHz?

It depends on the length of the unterminated cable is but probably 50 ohms.  70 MHz is just on the edge of being problem and if tested with a reference level pulse generator; there is probably a visible step in the response.

There is actually a good reason not to calibrate the output assuming a terminated cable and use a 1 Mohm input; the termination accuracy degrades the gain accuracy.

[bktemp]

I have an old Hantek 60Mhz 2150 USB oscilloscope which I could run off a battery pack.

I am going to try out a USB isolator using the AD chip and see if I can make the Hantek run in a useful manner on USB 1.1. You can buy 1500V isolator boards on Ebay for about A$15. Also have some 100x 2500V 100MHz probes on order for about the same price. Don't have any projects planned for this - probably just trying to find a use for the Hantek scope.

http://www.ebay.com/itm/381860044223

Looking at the pictures, I doubt those isolator boards are useable for anything near 1kVpeak: The DC/DC looks like a cheap one rated for only 500Vpeak isolation voltage with the primary and secondary winding wound on top of each other without rainforced insulation.

[amspire]

You are right - I hadn't looked closely. That is great - I can take it off. I have power both sides.

[capt bullshot]

If suitable components are used, then usually it is the printed circuit board material which changes (or starts out bad) screwing up the high impedance compensated dividers.  Tektronix called this "hook" and before qualifying standard fiberglass weave printed circuit board material, early on they used boards made from plastics like polysulfone (amber looking) for their high impedance attenuators and later a white board material that I have not identified yet.

Yes, that PCB material issue isn't totally unknown to me, wrong material can screw up your circuit. But I don't know anything about PCB material parameter change over time. Sometime it's better to use Teflon standoffs or similar construction techniques - way to expensive for todays world.

Jim Williams had something to say about maladjusted probe compensation:

"The translation of this statement is to hide the probe when you are not using it.  If anyone wants to borrow it, look straight at them, shrug your shoulders and say you don't know where it is.  This is decidedly dishonest, but eminently practical.  Those finding this morally questionable may wish to re-examine their attitude after producing a day's worth of worthless data with a probe that was unknowingly readjusted." - page 12 of Linear Technology application note 49)

Thanks for that quote! I remember having read this some time, and sometimes I follow his advice, like "yes, you may borrow the scope but find your own probes".

[David Hess]

If suitable components are used, then usually it is the printed circuit board material which changes (or starts out bad) screwing up the high impedance compensated dividers.  Tektronix called this "hook" and before qualifying standard fiberglass weave printed circuit board material, early on they used boards made from plastics like polysulfone (amber looking) for their high impedance attenuators and later a white board material that I have not identified yet.

Yes, that PCB material issue isn't totally unknown to me, wrong material can screw up your circuit. But I don't know anything about PCB material parameter change over time. Sometime it's better to use Teflon standoffs or similar construction techniques - way to expensive for today's world.

The Tektronix article discusses problems with epoxy resins so I wonder if it would change over time if improperly cured.  Humidity is also a problem with some board materials.  I suspect I have run across problems with hook in connection with dual slope integrating analog to digital converters.

I think the lesson is to either use the right board material to start with or include a charge test circuit as described in the article for quality control.

[thm_w]

I don't think people realise how much these probes currently sell for. You can't even buy a cheapie ebay or Aliexpress 25MHz job for $200, let alone a quality 70MHz one.

https://www.aliexpress.com/item/New-Professional-Differential-probes-DC-25Mhz-ADP25-Max-Voltage-1300V-1000V-RMS/946453698.html
https://www.globalmediapro.com/dp/A01LT0/Pintek-DP-25-Differential-Probe-25MHz-1000V/

$183 25MHz
$290 65MHz

Teardown: https://www.eevblog.com/forum/testgear/teardown-pintek-dp-25-differentail-probe/

[technogeeky]

Just discovered an embarrassing issue that will delay shipment of the fist batch.
#NotMyFault

Hi,

Are the red and black leads, + plus and - minus mixed up? They are different than other sapphire probes.



Regards,

Jay_Diddy_B

That would be pretty embarrassing...

[alanb]

Just discovered an embarrassing issue that will delay shipment of the fist batch.
#NotMyFault

If you've a batch with the leads the wrong way round I would take one off your hands for £50!

[amspire]

Just discovered an embarrassing issue that will delay shipment of the fist batch.
#NotMyFault

If you've a batch with the leads the wrong way round I would take one off your hands for £50!

Might be more serious then that - they might have accidentally made it out of antimatter. The charges reverse with anti-matter.

[Jay_Diddy_B]

Hi,

Here is another picture of a 70MHz sapphire probe:



The red lead is on the left.

I am not sure if this is the same as the EEVBlog HVP70.

Regards,

Jay_Diddy_B

[nidlaX]

I don't know about that. If someone was selling good $50 differential probes, I think people would just buy them as a standard part of their scope kit. I just assume that it is hard to achieve a good safe $50 differential probe.

$50 retail, very likely not easy.

I think you might be in for a shock in the upcoming weeks.

[SKPang]

They are in stock. Just ordered one from Dave's store.

[neslekkim]

Ordered this morning, saw they was going kinda fast, so didn't dare to wait

But some hours later, Dave posted this:
https://twitter.com/eevblog/status/854645548795568130

Crap.. Didn't know there was an newsletter even..

[EEVblog]

Hi,
Here is another picture of a 70MHz sapphire probe:
The red lead is on the left.
I am not sure if this is the same as the EEVBlog HVP70.

It's not. That's a different high voltage model.
My unit is a new design and is not on the market yet AFAIK (well, it is now)
70MHz for the price of the old 25MHz model.

[rsjsouza]

Dave, I just received the e-mail and it looks really nice! Too bad I can't spare that chunk of change at the moment... (already spent above my grade on the local auction in your other thread).

[mikeselectricstuff]

teardown?

[Electro Detective]

70 mhz diff probe for the price of a 25 mhz is a rippa deal. 

Now if someone retailed the generic 25 mhz differential probes in matched PAIRS for $300 (aussie dollar),

and 4 for $500, that sounds like a winner too 

Perhaps  20+ scope owners might consider to sell a scope or two to invest in safety and decent isolation practices,

and save a scope or two, plus a life   

[EEVblog]

teardown?

I did take some pics, but can't find them 
I believe it's very similar to the existing SMD design (not the through hole design I did a teardown video of), but they have obviously somehow tweaked it for 70MHz instead of 25MHz.
It has a couple of wires on the back of the board which I at first thought were mod wires, but they assure me they are part of the design and are a performance tweak for the double sided PCB layout.

[bitseeker]

Ooh, secret chips.

[JonM]

Ooh, secret chips.

If you go to Sapphire's Web site there is a flashing note that takes you to this URL:

  http://www.sapphire.com.tw/notify.pdf

So, they probably want to make it more difficult for Pintech to copy this probe.

[tautech]

Ooh, secret chips.

If you go to Sapphire's Web site there is a flashing note that take you this URL:

  http://www.sapphire.com.tw/notify.pdf

So, they probably want to make it more difficult for Pintech to copy this probe.

Exactly.

[jacklee]

May I know how much is it?

[tautech]

May I know how much is it?

Link to Dave's shop:
https://www.eevblog.com/product/hvp70/

[neslekkim]

would be nice if these would be not too expensive for hobbyists..  $200?, $250?

You'll have to buy a cheapie on ebay to get that price.

It ended up to be not so far from, $350, I was thinking US$, you use AU$, luckily the exchangerate is in my direction
Mine is hiding somewhere between Frankfurt, Germany, and Oslo, Norway now... hope it arrives soon.

[JonM]

Mine was transferred from DHL to NZ Post in Auckland this morning and now appears to be on some airline flight, hopefully to the US. I guess that some system determined that to be a good route rather than having DHL transport it to the US.

[bitseeker]

Mine says, "Delivery by NZ Post", but went directly from Sidney to the US. So far, so good.

[gnavigator1007]

Mine just arrived today!

[bitseeker]

That's great. The last whereabouts of mine was at the point of entry in Los Angeles.

[EEVblog]

Mine was transferred from DHL to NZ Post in Auckland this morning and now appears to be on some airline flight, hopefully to the US. I guess that some system determined that to be a good route rather than having DHL transport it to the US.

DHL Global Mail from Australia use Air NZ flights I believe.

[dr.diesel]

Mine arrived today as well, thanks Dave!

[gnavigator1007]

DHL tracking crapped out on mine back on the 26th. Had 3 updates that started at 3:50 am. First said arrival in destination country. 10 minutes later it said transport to destination country. 4 hours after that I got another that said arrival in destination country.  Was surprised and happy to see it stuffed in my mailbox today 

[bitseeker]

Yeah, DHL's tracking is kind of screwy. I later found that if you click on the NZ Post tracking number, you get more detail on their tracking page.

[haoleboy]

Got mine today!! Thanks Dave, it looks great! 

[EEVblog]

Yeah, DHL's tracking is kind of screwy. I later found that if you click on the NZ Post tracking number, you get more detail on their tracking page.

Please be aware that this is NOT the DHL courier service with courier level tracking. It is DHL Global Mail service which hands off to various other local postal carriers.
You don't always get end-end delivery notice or precise location or status tracking.

[bitseeker]

Thanks, Dave. I haven't received an item via DHL Global Mail before.

[neslekkim]

Yeah, DHL's tracking is kind of screwy. I later found that if you click on the NZ Post tracking number, you get more detail on their tracking page.

Please be aware that this is NOT the DHL courier service with courier level tracking. It is DHL Global Mail service which hands off to various other local postal carriers.
You don't always get end-end delivery notice or precise location or status tracking.

thanks for using this service, I think this is the best way. I was a bit scared at first thinking that dhl was going to know on my door, but luckily it's the local postal service instead.
dhl, ups, fedex, etc, is just a mess when delivering to home addresses, and even worse if I get them to deliver to my company/work address, since then, my company will receive the tax bills..

[BBBbbb]

Yeah, DHL's tracking is kind of screwy. I later found that if you click on the NZ Post tracking number, you get more detail on their tracking page.

Please be aware that this is NOT the DHL courier service with courier level tracking. It is DHL Global Mail service which hands off to various other local postal carriers.
You don't always get end-end delivery notice or precise location or status tracking.

thanks for using this service, I think this is the best way. I was a bit scared at first thinking that dhl was going to know on my door, but luckily it's the local postal service instead.
dhl, ups, fedex, etc, is just a mess when delivering to home addresses, and even worse if I get them to deliver to my company/work address, since then, my company will receive the tax bills..

DHL and custom clearance give me the creeps.
Their local office for customs handling here is probably the last to go to if you need something off the customs. I've even heard from other people stories where they would go into the customs procedure w/o an authorization from the recipient (they need to ask you who do you want to handle the clearance) and then charge you nicely for the services (a friend recently refused to accept a package as they wanted to charge 30eur for services only, for something that was also in that price range). And they would ask you for documents no other forwarder would ask, under the justification that the Customs needs it.

Transport wise they are great, but if I have anything that might catch the customs officer's eye I don't want them.

[EEVblog]

DHL and custom clearance give me the creeps.
Their local office for customs handling here is probably the last to go to if you need something off the customs.

Unfortunately I ship to over 150 countries, and each one has their own customs requirements.
Its is literally impossible to find a service that works well in every country.

[BBBbbb]

DHL and custom clearance give me the creeps.
Their local office for customs handling here is probably the last to go to if you need something off the customs.

Unfortunately I ship to over 150 countries, and each one has their own customs requirements.
Its is literally impossible to find a service that works well in every country.

I know, just stating the situation here.
Many use local delivery companies as partners in many smaller markets, so there is no way of having a good choice that fits all.

[neslekkim]

Yeah, DHL's tracking is kind of screwy. I later found that if you click on the NZ Post tracking number, you get more detail on their tracking page.

Please be aware that this is NOT the DHL courier service with courier level tracking. It is DHL Global Mail service which hands off to various other local postal carriers.
You don't always get end-end delivery notice or precise location or status tracking.

thanks for using this service, I think this is the best way. I was a bit scared at first thinking that dhl was going to know on my door, but luckily it's the local postal service instead.
dhl, ups, fedex, etc, is just a mess when delivering to home addresses, and even worse if I get them to deliver to my company/work address, since then, my company will receive the tax bills..

DHL and custom clearance give me the creeps.
Their local office for customs handling here is probably the last to go to if you need something off the customs. I've even heard from other people stories where they would go into the customs procedure w/o an authorization from the recipient (they need to ask you who do you want to handle the clearance) and then charge you nicely for the services (a friend recently refused to accept a package as they wanted to charge 30eur for services only, for something that was also in that price range). And they would ask you for documents no other forwarder would ask, under the justification that the Customs needs it.

Transport wise they are great, but if I have anything that might catch the customs officer's eye I don't want them.

Yes, but this way, for me atleast, it's the postalsystem that handles the customs etc, not dhl, since the package is handed over to the postalsystem from Germany to Norway.

[BU508A]

Tension is increasing 

[Towger]

Unfortunately I ship to over 150 countries, and each one has their own customs requirements.
Its is literally impossible to find a service that works well in every country.

Standard parcel post Dave, as you used before.

DHL, UPS etc in recent times are not worth the hassle, with their extra charges, paperwork and excess taxes etc.  If the sender does not put 3 copies if a fully itemised invoice on the outside they will make up values.
 
Even the likes of TI cannot manage paperwork to their exacting requirements from the States, so you end up jumping through hoops to get a 30 dollar dev board delivered.  Actually in that case I just ignored them, as I was on holidays in Melbourne for a few weeks, but they were ringing the office looking for me and send me emails galore looking for our import agents details!  I think they miss read the invoice and thought it was worth 30k.

I the end I arrived back from Holidays and found the package delivered, and no charge has arrived,  yet.

BTW If it comes from China, they make up values/charges anyway.

Another of their tricks for items with free or no itemised delivery charge, is to charge tax on the cost of returning the package to the country of origin, using their express local rates.  I got caught out on that one last year on a cheap replacement PSU from China with free courier (FedEx I  think it was in this case) delivery.  The whole lot cost from memory about $45 for two of them delivered.   They valued the delivery at well over €100. They claim they have to do this by law...

But chances are an item by standard post will just sail in and be delivered FOC by the local postie. Who might on a bad day look for vat, based on the declared value.

[EEVblog]

Unfortunately I ship to over 150 countries, and each one has their own customs requirements.
Its is literally impossible to find a service that works well in every country.

Standard parcel post Dave, as you used before.

Which had basically no tracking at all, cost more, was more hassle to send, and almost always got stuck in customs in a handful of countries like Germany.
At one point I had to totally stop shipping to Germany using Australia post.

DHL Global mail is much better in every respect.

DHL, UPS etc in recent times are not worth the hassle, with their extra charges, paperwork and excess taxes etc.

DHL Global Mail is NOT like regular DHL courier.
And I can assure you it is far less hassle, is lower in cost, and has less paperwork.

[neslekkim]

DHL, UPS etc in recent times are not worth the hassle, with their extra charges, paperwork and excess taxes etc.

DHL Global Mail is NOT like regular DHL courier.
And I can assure you it is far less hassle, is lower in cost, and has less paperwork.

I really don't see the problem, the way you shipped these was the best for me atleast, I don't need to worry about DHL or other couriers, the postalservice delivered the package, so I just need to go to the postaloffice now and pay my tax and get the package.
No paperwork, no excess taxes or stupid fees.

Can't wait to get home to pick it up.

[bitseeker]

NZ Post's tracking stopped on April 26 when it arrived in Los Angeles. I couldn't find any reference for tracking upon handoff to USPS. So, I guess DHL doesn't update for the final leg. Hopefully, it isn't stuck in customs. I'll give it a couple more days.

[rch]

Got mine after only three days of tracking silence in the UK.   And they forgot to charge VAT, which saved me the UK Royal Mail handling charge too.  Can't be bad.  (This isn't unique, Royal Mail forget to do customs processing about one parcel in ten in my experience - just have to hope it's the expensive ones.)

Edit:   I just got a plumbing part from the US by the same DHL system.  With this, DHL never tracked it at all, and denied the existence of the tracking number, but I still got it in fourteen days.  So I'm relatively pleased with DHL at the moment.

[neslekkim]

Mine got tracking info like this:

http://webtrack.dhlglobalmail.com/?trackingnumber=AUBCN000913056

Got silent the morning 26. april, but the right hand side got updated with new trackingnumber: RX569451927DE wich is the local post, and I got update yesterday
https://sporing.posten.no/sporing.html?q=RX569451927DE&lang=en
and picked it today.
So I think the dhl global mail tracks through dhl from australia to the last sorting hub where it's handed over to the local postal service, so I would guess you would find local trackingnumber on the page like I did.

[bitseeker]

I was expecting the DHL tracking page to replace the NZ Post tracking number/link with one for USPS (or append it), but that hasn't happened. Since these have already been delivered to Colorado and Florida, I'm a bit worried as I'm in California, i.e., the same state it arrived in on April 26. But it could just show up any day now.

[TheAmmoniacal]

Mine got tracking info like this:

http://webtrack.dhlglobalmail.com/?trackingnumber=AUBCN000913056

Got silent the morning 26. april, but the right hand side got updated with new trackingnumber: RX569451927DE wich is the local post, and I got update yesterday
https://sporing.posten.no/sporing.html?q=RX569451927DE&lang=en
and picked it today.
So I think the dhl global mail tracks through dhl from australia to the last sorting hub where it's handed over to the local postal service, so I would guess you would find local trackingnumber on the page like I did.

How much did they charge you in VAT and customs handling fee? (25% + 140 NOK?)

[neslekkim]

yes, 160NOK in vat, and 153NOK in fee, not bad

[rch]

I was expecting the DHL tracking page to replace the NZ Post tracking number/link with one for USPS (or append it), but that hasn't happened. Since these have already been delivered to Colorado and Florida, I'm a bit worried as I'm in California, i.e., the same state it arrived in on April 26. But it could just show up any day now.

I think every country's postal service is different.  Certainly the Royal Mail service in the UK that DHL hands over to is *not* a tracked service.   A tracked service would cost about half of the total money Dave charges for the DHL service so DHL are not likely to pay it.  So there was no tracking number issued for my local postal service  and DHL just tracked the parcel onto the international plane.

[JonM]

I was expecting the DHL tracking page to replace the NZ Post tracking number/link with one for USPS (or append it), but that hasn't happened. Since these have already been delivered to Colorado and Florida, I'm a bit worried as I'm in California, i.e., the same state it arrived in on April 26. But it could just show up any day now.

My HVP-70 also passed through LA on April 26. There was no tracking handoff to USPS by either DHL or NZ Post, however I am happy to announce that it arrived today in Central Virginia.

Soon I will be looking at my mains voltage with Ethernet over powerline signals, then probing various audio amplifiers to see how the noise propagates through one with a big toroidal transformer, but not through cheaper amps... It will be nice to do this in a worry free manner(at least in terms of not blowing up the scope with a slip of a probe).

[kilobyte]

According to the Tracking Code mine has now arrived at the local customs.
So in a couple of days I should get a letter that says it's ready to pick it up.

[oewean]

Is it the Sapphire SI-9071?
Sapphire has top notch products 

[bitseeker]

Probe finally arrived. Slowly, but surely.

Thanks, Dave!

[ModemHead]

Another one arrived in North Carolina today.  In case anyone has not mentioned it, the NZ Post code works in the USPS tracking system.

[bitseeker]

I didn't know that. Sure enough, all the tracking is in there. Thanks, ModemHead.

[hendorog]

Mine was transferred from DHL to NZ Post in Auckland this morning and now appears to be on some airline flight, hopefully to the US. I guess that some system determined that to be a good route rather than having DHL transport it to the US.

DHL Global Mail from Australia use Air NZ flights I believe.

Pointing out the obvious but Air NZ != NZ Post.

DHL must be routing packages out into the postal system through NZ for some reason??

Another one arrived in North Carolina today.  In case anyone has not mentioned it, the NZ Post code works in the USPS tracking system.

This is standard procedure when I import non courier packages. I go to the source country postal tracking service first to track the package within the country of origin. That will normally show when the package leaves the source country.
Then go to the nzpost tracking service and track it to delivery at my house.
In both cases I use the tracking number provided by the sender of the package.

[VierZylinder]

Dave,

First post here and a question. I was using a gaggle of Keysight N2791A's here at work when I decided, "you know, I probably ought to sack up and buy myself a diff probe". I knew these weren't too bad, about $700 USD but that's more than I wanted to spend. I was delighted to find your Sapphire (same as Keysight) unit for $399 on Amazon.com.

Having said all that I noticed you made a comment regarding finding an embarrassing mistake that affected the first units getting out. Did any go out with issues I should be weary of, is the Amazon one ok? You'd posted a photo of the SMT versions innards and the board markings for + and - inputs do not align at all with how the leads come out of the unit unless they're criss-crossed internally.

Regards,

James R.

[BU508A]

My EEVBlog HVP-70 arrived today. Shipping started on 28th of April. But the best is: German customs put this green sticker on it, so I wasn't charged with additionals fees, taxes etc.

http://philaseiten.wavecdn.net/up/781551/0/5/ea15b1ec_h.jpeg

Dave, it seems that it was a good idea to switch to DHL global services. No hassle with German customs so far. 

And I want you to thank you for all your efforts and making such things available to us for a really reasonable price.
Much appreciated!

Thank You!

Andreas

[kkessler]

I'm working on switching and transformerless capacitor power supplies to power small uCs from mains, and even though I connect my devices to an isolation transformer, I still pull out my old Rigol oscilloscope for testing, instead of risking my new R&S.  I decided I needed a differential probe for this, so I started googling around, and I came across this probe at Amazon. I had never heard of an EEVBlog Differential Probe before, so I thought it might be some sort of scan with someone putting an EEVBlog sticker on their own probes, to take advantage of Dave's good name.  I came here, though, and found it was a legitimate product, and it rose to the top of my list.

Looking around at Aliexpress, I see some probes under the name Cleqee, specifically the YP5210, which claims 100MHz at $70 less than the EEVBlog one.  Has anyone heard of any reports on these probes?

[EEVblog]

Having said all that I noticed you made a comment regarding finding an embarrassing mistake that affected the first units getting out. Did any go out with issues I should be weary of, is the Amazon one ok?

All units shipped are fine.
It was the x10 / x100 text that was swapped.
The +/- was swapped too in the early photos they sent me, but I caught that before I got my first unit to play with.

[EEVblog]

Looking around at Aliexpress, I see some probes under the name Cleqee, specifically the YP5210, which claims 100MHz at $70 less than the EEVBlog one.  Has anyone heard of any reports on these probes?

It'll probably work ok, but it's x100 and x1000, designed for higher voltage stuff. I prefer the x10 / x100 units that are more usable on lower voltage stuff.

[EEVblog]

BTW, the HVP70 is cheaper on my website (as Amazon take 18%) if you want to wait a bit longer for delivery.

[neslekkim]

Looking around at Aliexpress, I see some probes under the name Cleqee, specifically the YP5210, which claims 100MHz at $70 less than the EEVBlog one.  Has anyone heard of any reports on these probes?

It'll probably work ok, but it's x100 and x1000, designed for higher voltage stuff. I prefer the x10 / x100 units that are more usable on lower voltage stuff.

What do you regard as high and low voltage in this scenario?, since this is an High voltage probe that is.

[alank2]

I noticed in the Amazon listing it says it requires lithium ion batteries - Is this a lithium AA ?  Why won't alkalines work?  (assuming they do not)

[EEVblog]

What do you regard as high and low voltage in this scenario?, since this is an High voltage probe that is.

For me, high voltage = 240V mains, which a x100 mode HVP70 does easily.
And the x10 mode is great for lower voltage stuff like motor drive and other SMPS work for example.

[EEVblog]

I noticed in the Amazon listing it says it requires lithium ion batteries - Is this a lithium AA ?  Why won't alkalines work?  (assuming they do not)

That's a mistake. Amazon has horrible listing with tons of non-relevant fields.
Normal AA's, look at the package photo.

[alank2]

That's a mistake. Amazon has horrible listing with tons of non-relevant fields.
Normal AA's, look at the package photo.

I thought they looked normal!  Excellent.

[kkessler]

BTW, the HVP70 is cheaper on my website (as Amazon take 18%) if you want to wait a bit longer for delivery.

You talked me into it.  After the shipping and the exchange rate, your cost was $40 less than Amazon's, and all it cost me was the 2 day delivery, which I didn't need in this case.  Mains is the highest voltage I foresee working on, and mine is only 120V, so this probe looks more than sufficient to me.

[bitseeker]

Yep, it should work a treat, kkessler. I had looked at various probes before Dave announced his and some can take really high voltages. However, the drawback is that the multiplier is too high for not-so-high voltages. So, I was pleased to see this one, which is a nice balance of voltage ranges, bandwidth, and price.

Although some lament that a single differential probe like this costs as much as a low-end scope, I find that the combination of the HVP-70 and DS1054Z is a great deal for safety and capability. Together, it's still less than the cost of some other entry-level scopes alone.

[mtdoc]

Yes, the 10x and 100x is a good balance for most and this is a good price.

Because I already have a Tektronix P6046 to handle lower voltage differential needs and because I came across a good deal on a Tektronix p5205 which is 50X and 500X with 100MHz bandwidth, I went with that.  Otherwise I would have gone with Dave"s.

In case anyone is looking for a case for their new probe,  I've ordered on of these inexpensive cases from eBay.  They should work well for Dave's probe a well.  I'll report back when I get mine.

[EEVblog]

FYI, the "bagainprobe" coupon code is working again, with 12% discount.
And if you have bitcoins, I accept those in the shopping cart. With the bitcoin price going parabolic, it's cheaper than ever.

[mtdoc]

In case anyone is looking for a case for their new probe,  I've ordered on of these inexpensive cases from eBay.  They should work well for Dave's probe a well.  I'll report back when I get mine.

Just following up on this. After a month this case finally arrived. It's a nice case. Unfortunately it's just a bit too small for my Tek p5205. I thought it would work based on the listed OD but the shell is thick enough that the ID is significantly smaller.

The inside dimensions are 8 1/8 " x 3 3/4" x 1 1/2".    Not sure if that will accommodate the HVP70 or not.

It does fit my Tek A6302 current probe quite nicely, so I'll keep it for that.

[BU508A]

The inside dimensions are 8 1/8 " x 3 3/4" x 1 1/2".    Not sure if that will accommodate the HVP70 or not.

Here are the dimensions of the case in metric:
206.375mm * 95.25mm * 38.1mm

The dimensions of the EEVBlog HVP-70:

~195mm * ~75mm * ~31mm

So, it should fit, sort of, a bit more space in length and width would be nice.

[Neomys Sapiens]

Could/would you offer a variant with a TekProbe2 interface?

[LabSpokane]

I just got my HVP in.  Thanks, Dave!

<incorrectness removed>
==================================
Edited: 

There turns out to be NO problem.  I accidentally had the probe input on the HVP set for AC coupling, which is wrong.  Setting the input for DC coupling renders a perfect waveform.  Sorry for the false alarm.

[mtdoc]

On the attached image, green is the isolation xformer output.  Yellow is the diff probe. 

 I assume the difference in displayed amplitude is due to scaling differences. Are the actual amplitudes the same?

[daveyk]

Looks sweet!

Simple request: amplified small Signal differential probe for small monies. The Tek one cost something like $4500.


Sent from my iPhone using Tapatalk

[casinada]

Has anybody have the chance to evaluate the Hantek HT8050 and HT8100 Differential probes?
It is a x50 and x500 like the Tektronix P5200
It would be nice if somebody has the resources to compare all these probes side by side.

http://www.ebay.com/itm/282370784441?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[Someone]

On the attached image, green is the isolation xformer output.  Yellow is the diff probe. 

I assume the difference in displayed amplitude is due to scaling differences. Are the actual amplitudes the same?

Its not the amplitudes in question but the distortion, some slew rate limitations and odd corners in the peaks (recovery from the slew limiting?).

[LabSpokane]

On the attached image, green is the isolation xformer output.  Yellow is the diff probe. 

 I assume the difference in displayed amplitude is due to scaling differences. Are the actual amplitudes the same?

Amplitudes are on scope different due to scaling settings, yes.  Amplitudes between diff probe and and direct measurement are different due to the diff probe scaling the voltage into a range of 0-7V.

[David Hess]

Its not the amplitudes in question but the distortion, some slew rate limitations and odd corners in the peaks (recovery from the slew limiting?).

Slew rate limiting on a 60Hz sine wave?  Better not be.

[Monkeh]

Amplitudes are on scope different due to scaling settings, yes.  Amplitudes between diff probe and and direct measurement are different due to the diff probe scaling the voltage into a range of 0-7V.

It's not scaled into 0-7V, it's x10 or x100 attenuation. That or it's a very odd device.

Test the probe with a known clean source - stuffing your mains through an isolation transformer is not the same as looking at it with a normal probe.

[LabSpokane]

See above.  User error.  I had the scope input set for AC instead of DC coupling.  DC coupling is the correct setting since the output is single-ended. 

[LabSpokane]

Amplitudes are on scope different due to scaling settings, yes.  Amplitudes between diff probe and and direct measurement are different due to the diff probe scaling the voltage into a range of 0-7V.

It's not scaled into 0-7V, it's x10 or x100 attenuation. That or it's a very odd device.

Test the probe with a known clean source - stuffing your mains through an isolation transformer is not the same as looking at it with a normal probe.

Ignore that.  I should never answer a question in a hurry.  You are absolutely correct.  I was referring to the amplitude of the actual mains voltage versus the probe instead of the 1:10 signal into the scope. 

[mtdoc]

On the attached image, green is the isolation xformer output.  Yellow is the diff probe. 

I assume the difference in displayed amplitude is due to scaling differences. Are the actual amplitudes the same?

Its not the amplitudes in question but the distortion, some slew rate limitations and odd corners in the peaks (recovery from the slew limiting?).

Yes, I realize distortion was the original point, but my question was about amplitude.

So accounting for scaling differences, what is the difference in amplitude? (either with or without isolation transformer).

[LabSpokane]

On the attached image, green is the isolation xformer output.  Yellow is the diff probe. 

I assume the difference in displayed amplitude is due to scaling differences. Are the actual amplitudes the same?

Its not the amplitudes in question but the distortion, some slew rate limitations and odd corners in the peaks (recovery from the slew limiting?).

Yes, I realize distortion was the original point, but my question was about amplitude.

So accounting for scaling differences, what is the difference in amplitude? (either with or without isolation transformer).

Dead issue.  I had my probe input setup incorrectly, despite the fact that it was literally staring me in the face.  The device is in perfect working order.  It's user ... is another discussion entirely.   

[mtdoc]

Dead issue.  I had my probe input setup incorrectly, despite the fact that it was literally staring me in the face.  The device is in perfect working order.  It's user ... is another discussion entirely.   

OK, got it. No worries, I have a lot of experience with the same kind of "intra-cerebral device error".

[serggio]

Subscribing   

[BU508A]

In case anyone is looking for a case for their new probe,  I've ordered on of these inexpensive cases from eBay.  They should work well for Dave's probe a well.  I'll report back when I get mine.

Just following up on this. After a month this case finally arrived. It's a nice case. Unfortunately it's just a bit too small for my Tek p5205. I thought it would work based on the listed OD but the shell is thick enough that the ID is significantly smaller.

The inside dimensions are 8 1/8 " x 3 3/4" x 1 1/2".    Not sure if that will accommodate the HVP70 or not.

It does fit my Tek A6302 current probe quite nicely, so I'll keep it for that.

I've bought this case for my EEVBlog HVP70 probe:

http://www.ebay.com/itm/222524750968
It costs EUR 16,54 / ca. U$ 18,60
and I'm very pleased about the quality.   

Here are some pictures:

[Monadnock]

I got an email this morning, supposedly from Dave, saying the BARGAINPROBE discount was working again, but when I went to check out it said that the discount use limit had already been reached.

Anyone else get this email? I'm wondering if it was spam.

[rsjsouza]

I got an email this morning, supposedly from Dave, saying the BARGAINPROBE discount was working again, but when I went to check out it said that the discount use limit had already been reached.

Anyone else get this email? I'm wondering if it was spam.

I got this e-mail today as well but I haven't tried to use the code. I just did and it worked for me.

[Monadnock]

I got an email this morning, supposedly from Dave, saying the BARGAINPROBE discount was working again, but when I went to check out it said that the discount use limit had already been reached.

Anyone else get this email? I'm wondering if it was spam.

I got this e-mail today as well but I haven't tried to use the code. I just did and it worked for me.

I got that far as well. It didn't strip out the discount on me until I clicked PayPal to pay.

It would of been better if it just refused to accept the code instead of accepting it and then taking it out when you go to pay.

[neslekkim]

In case anyone is looking for a case for their new probe,  I've ordered on of these inexpensive cases from eBay.  They should work well for Dave's probe a well.  I'll report back when I get mine.

Just following up on this. After a month this case finally arrived. It's a nice case. Unfortunately it's just a bit too small for my Tek p5205. I thought it would work based on the listed OD but the shell is thick enough that the ID is significantly smaller.

The inside dimensions are 8 1/8 " x 3 3/4" x 1 1/2".    Not sure if that will accommodate the HVP70 or not.

It does fit my Tek A6302 current probe quite nicely, so I'll keep it for that.

This was actually a very nice case, the probe fits perfectly into it. Would be nice if it was teensy bit longer, but no problem packing it and closing the case.

[bitseeker]

8-1/8" long does seem a bit tight. The leads must get pretty well bend to fit. I guess I'll look for something a bit longer. For now, I just pack it in my scope's bag.

[neslekkim]

It looks like this:

[bitseeker]

Thanks for the photo. Looks like it works better than a ruler would lead one to expect. Nice.

[EEVblog]

It looks like this:

Nice.

[EEVblog]

FYI I'm having a 15% sale on the EEVblog store including the HVP70 probe.
Use the coupon code hardfork

https://www.eevblog.com/store/

[EEVblog]

Is it supposed to work in your EEVBlog store on Ebay? Because it didn't work for me. I might have made a mistake typing it in but I don't think I did and it blanked it out when telling me it wasn't valid.

It was just a bunch of fuses.

No, only my web store

[NiHaoMike]

Any teardowns? I opened up mine but didn't go any further once I found that the shielding is soldered on.

I think it's a good product, but I would have liked it better if the banana jacks were on the isolator box instead of the probes themselves. Making the BNC cable detachable would also be good, but I can understand that doing so will add cost.

For a test, I probed the mains with a Homeplug adapter streaming a TV show. The packets look tiny compared to the mains, so I put together a frequency dependent attenuator to make the packets easier to see.

[tautech]

I like the Pintek ones better.

They are clones of Sapphire:
http://www.sapphire.com.tw/notify.pdf

Actually not.

The pdf linked refers to Pintech.
Pintek and Pintech are two different companies, one in Taiwan as Sapphire are and Pintech famous for copying Pintek and apparently Sapphire too are in China.

[bicycleguy]

Ordered from EEVblog Nov 5th, received Nov 13th, DHL to USmail,  US$ 379.82 via PayPal

Amazon was asking $650 at the time, now they are asking $450 ?

Seems nice, solid, nice detachable probes.  Here's a picture of the 60hz 120VAC at the wall outlet compared to a nice sine wave.  Is home power always this distorted?  This was in the evening so no solar distortion.

[bicycleguy]

Ordered from EEVblog Nov 5th, received Nov 13th, DHL to USmail,  US$ 379.82 via PayPal

Amazon was asking $650 at the time, now they are asking $450 ?

Seems nice, solid, nice detachable probes.  Here's a picture of the 60hz 120VAC at the wall outlet compared to a nice sine wave.  Is home power always this distorted?  This was in the evening so no solar power generation distortion.  Be neat to see a separate thread on where in the world the worst distortion is.

[TheSteve]

This is what the AC currently looks like at my place (different differential probe) - minimal load at the moment.

[David Hess]

Here's a picture of the 60hz 120VAC at the wall outlet compared to a nice sine wave.  Is home power always this distorted?  This was in the evening so no solar distortion.

In my experience it is usually even more bent at the top of the leading edge do to non-linear rectifier-capacitor input filters.  Things may have improved with more power factor corrected loads.

[Dubbie]

Has anyone found any nicer probes for the thing?

I really don't like the ones that come with them. They are really hard to open up sometimes if you are in a tight space or funny angle.

[JonM]

Has anyone found any nicer probes for the thing?

I really don't like the ones that come with them. They are really hard to open up sometimes if you are in a tight space or funny angle.

probemaster.com has many choices for probe connections. For AC mains, I have a couple of banana to "big metal blade" that came with a Triplett wire tracer. I will probably keep them with my HVP-70 since I don't use the wire tracer very often.

[Dubbie]

My favourite bench meter probes are probemaster so I did check out their site. They didn’t seem to have anything suitable.

[JonM]

My favourite bench meter probes are probemaster so I did check out their site. They didn’t seem to have anything suitable.

Upon further study it appears that I have only one Probemaster probe that fits the HVP-70 leads, and it it insulation piercing which may not be appropriate for HV work.

Because the HVP-70 leads do not have retractable sheaths (maybe a requirement of 1000V Cat III ?) only select probe adapter will work. In the photo, from the top:

 - "Big blade" mains probe from Triplett wire tracer
 - Big alligator clip marked 1000V Cat III, possibly from Fluke Scopemeter kit
 - The original HVP-70 probe, for reference
 - Minigrabber, probably from Franky: http://stores.ebay.com/99centhobbies
 - Probemaster 9174 Piercing Probe, marked 1000V Cat III

Looks like I may need a few more probes for the HVP-70.

[NiHaoMike]

I decided to finally do a teardown on mine and the build quality, while definitely not the worst I have seen, was nowhere as good as I was expecting. Three bodge wires that aren't even tacked down, a lot of other bodges, and poor soldering quality in general. There's also a trace routed under one of the switches such that tiny movements from use can cause it to short. The worst part is that I cannot touch it up (except the switch - very carefully bend the metal to give more clearance) because doing so will almost certainly affect the calibration.

Another odd part is that the chips were painted over in different colors. If it was to slow down reverse engineering, it was certainly ineffective since it only took a few minutes with a pocket knife to scrape it off and identify the important parts.

It looks like it uses basically two very well matched X100 attenuators with an impedance high enough to be considered isolated when used with mains voltage. It then goes to an AD8129, with a gain of 10, for the X10 mode and an AD8130, with unity gain, for the X100 mode. One switch selects which is used and a THS3061 drives the coax output. On the PSU side, there's a flyback converter with a very unusual transformer being driven by an unidentified chip with the markings 487D S18B. A common 393 drives the power LED.

[bicycleguy]

NiHaoMike,

Wow, as you noted that looks surprisingly crapy.  I opened mine to see if the same but chickened out at the metal cans.  I really like the unit and didn't want to risk messing it up.

Up to that point it looked good although the tamper stickers were easily defeated, however, the solder joints I could see between the cans looked as dirty and cold soldered as your's.  I have gotten a little cocky about safety since I started using this but seeing your pictures will hopefully make me sober up.

[Hydron]

Thanks for the pictures, I was interested in how this probe was constructed. The use of the AD8130/29 is unsurprising, they fit the bill well for a diff-probe (I have played around myself using them in exactly the same way).

The J1 and J2 "bodge" wires are actually probably designed to be there (in order to make it possible to construct with a 2 layer PCB), rather than being hacked in afterwards. They are only being used to switch between the 2 input chips (go to the shutdown pins), so could definitely be tacked down without any change to calibration. I can't tell what the third wire does from your photo - is there any chance of getting a clearer, high-resolution picture of the top of the PCB?

[Zbig]

Kinda ironic, considering Dave's eagerness to point out any PCB's (or product's overall) quality issues or general nastiness on every occasion, in no uncertain terms. I definitely won't rush to drop my $350 (current Amazon list price) on one anytime soon, unless I need one badly. Well, that's the lack of competition at works, I guess...

[bitseeker]

Well, I guess Dave needs to take a look at the recent batch of them and open one up. If their QC has dropped, I'm sure he'll say something about it.

I haven't torn mine down, but now I'm getting curious.

[TheSteve]

Hmmm, did Dave ever do a teardown on camera? It does look from the picture to be rather "how ya doing".

[bitseeker]

I don't recall, exactly. Might have been an actual Sapphire he took apart before?

Sent Dave a quick message to check out Mike's post. The forum is too big to keep track of everything.

[The Soulman]

Construction quality and overall design of the Dave probe seems very similar to the lecroy (sapphire) from video 932. 

[EEVblog]

I don't recall, exactly. Might have been an actual Sapphire he took apart before?

Sapphire make all the probes, including this one, Lecroy, Keysight and many others, they all re-badge Sapphire.

[NiHaoMike]

Is anything being done to address the problem so that newer units will be built with better quality?

[LaurentR]

I managed to get my hands on a few differential probes to compare noise levels for low-voltage use.
Compared:
* Pintek DP-25 25MHz X20/X50/X200. ~$300
* EEVBlog HVP70 70MHz X10/X100. $350 on Amazon US. This is a Sapphire design (not on their web site) and is now also available as the Cal Test CT4192 ($795) and Testec TT-SI 9071
* CT3688 200MHz X10 (really X5). $989 on Amazon US, but seen as low as $568. This is a Sapphire design (SI-200) and it is available under some other names like Testec TT-SI 200. Seems similar to the Keysight N2792A ($1917)

Note: The CT3688 is quoted as X10, but it's X10 "into 50 Ohms", so it's really a X5 probe for comparison.

Advertised noise levels are:
* DP-25: 1mv RMS = 20mV RMS input equivalent at X20.
* EEVBlog: 1.5mV RMS = 15mV RMS input equivalent at X10.
* CT3688: 0.3mV RMS = 3mV RMS input equivalent at X10 (really X5)

Below is a screenshot of the three probes with a shorted input. Std Dev at the bottom of the screen.

Comments:
* All probes are within spec with a bit of margin.
* The EEVBlog probe has a somewhat but not dramatically better noise level than the Pintek. It has more intrinsic output noise, but wins because of the 10X divider. However, the Pintek has proportionally more peak noise (p2p approx values for the 3 probes: 24mV, 110mV, 205mV).
* The CT3688 really has a much lower noise level than the others. It is the only probe I have seen that has a noise level substantially lower than 1mV output.

[bitseeker]

Interesting. Thanks for the comparisons. I also like having the X10 on the HVP70.

[s_lannan]

Hi There,
Went to buy one earlier today, noticed they were 'out of stock'
Does anyone have a rough ETA on when they'll return?

Thanks.

[Hydron]

* The CT3688 really has a much lower noise level than the others. It is the only probe I have seen that has a noise level substantially lower than 1mV output.

It may be a bit late (didn't see the post at the time), but would you happen to have a pic of the insides of the CT3688? Am interested in what they are doing to get the low noise level compared to the others. From the datasheet it looks to be lower input impedance than the others (which maybe do a 100:1 divider first then multiply by 10x for the 10:1 range - would explain extra noise), but it'd be nice to know what they're actually doing.

[bitseeker]

Went to buy one earlier today, noticed they were 'out of stock'
Does anyone have a rough ETA on when they'll return?

Dave discounted them not too long ago to clear out his inventory. So, it doesn't sound like they're coming back. However, I haven't heard definitively one way or the other.

[Octane]

Any update on those probes? Dave?

[Mechatrommer]

...One switch selects which is used and a THS3061 drives the coax output....

i just noticed this 2 years old post.. THS3061 is not designed for repetetive high slewrate more than 900V/us.. it will burn. so for ±700V input, it has to output ±14V swing to the 50 ohm termination to produce ±7V on the dso. if anyone can design a 1400V that contains about 30MHz harmonics, THS3061 will burn, for normal 240Vac system, limit your BW to 40MHz, this opamp is in my ban list. i guess why we dont see this thing burnt is because users mostly from 110Vac countries (can safely go to max 70MHz spec limit) or nobody built 1400V 30MHz circuit with it, so i guess for normal usage of target customers, its ok. better replacement is something like THS3091 imho, fwiw..

[EEVblog]

Went to buy one earlier today, noticed they were 'out of stock'
Does anyone have a rough ETA on when they'll return?

Dave discounted them not too long ago to clear out his inventory. So, it doesn't sound like they're coming back. However, I haven't heard definitively one way or the other.

Sapphire have apparently just found a buyer, so they have been saved from going under. But not sure about production of this probe, I think I can make another buy order though.
But I'm also currently investigating getting another probe customised to match the HVP70 specs.

[bdamson]

Hello, I'm an avid EEVblog watcher for few years now and this is my first forum post. I'm new to electronics and just purchased my first oscilloscope. +1 on interest in another Dave branded differential probe! 

[NiHaoMike]

i just noticed this 2 years old post.. THS3061 is not designed for repetetive high slewrate more than 900V/us.. it will burn. so for ±700V input, it has to output ±14V swing to the 50 ohm termination to produce ±7V on the dso. if anyone can design a 1400V that contains about 30MHz harmonics, THS3061 will burn, for normal 240Vac system, limit your BW to 40MHz, this opamp is in my ban list. i guess why we dont see this thing burnt is because users mostly from 110Vac countries (can safely go to max 70MHz spec limit) or nobody built 1400V 30MHz circuit with it, so i guess for normal usage of target customers, its ok. better replacement is something like THS3091 imho, fwiw..

It's designed to output to a 1M load, so the coax itself is the only significant load it sees.

[Tarloth]

THANKS DAVE! I'm really interested in a new differential probe!

[EEVblog]

FYI, I have more stock coming mid August.
No word on the other design yet.

[Vestom]

* CT3688 200MHz X10 (really X5). $989 on Amazon US, but seen as low as $568. This is a Sapphire design (SI-200) and it is available under some other names like Testec TT-SI 200. Seems similar to the Keysight N2792A ($1917)
Note: The CT3688 is quoted as X10, but it's X10 "into 50 Ohms", so it's really a X5 probe for comparison.

It does not make much sense to make a 200MHz probe into 1MOhms, so it is really a X10 probe. Running it without 50 Ohms termination will likely ruin your signal integrity and frequency response.

[CDaniel]

That's not true at all , the input impedance is 2x500Kohm and the probe has 5x attenuation into 1Mohm input oscilloscope and 10x into 50ohm . Because it has a 50ohm output series resistor ... You can use it anyway without ruining anything

[Vestom]

That's not true at all , the input impedance is 2x500Kohm and the probe has 5x attenuation into 1Mohm input oscilloscope and 10x into 50ohm . Because it has a 50ohm output series resistor ... You can use it anyway without ruining anything

Hmmm. Let us see about that:

• The CT3688 probe is specified to output into scope 50R termination: https://www.caltestelectronics.com/images/attachments/CT3688_datasheet_20170525.pdf
• The probe will then presumably be calibrated when driving a 50R termination. When driving 1M you will get full "benefit" of any tolerance in the source impedance. That will likely add some % DC tolerance.
• When driving 1MOhm you get a ~100% reflection. If your source termination or cable impedance is less than perfect you WILL get standing waves - and nothing is perfect...
• Your 1MOhm scope input will likely have a 10-20pF capacitance in parallel presenting an impedance of 40-80 Ohm @200 MHz and a significant phase angle. The CT3688 does not have any adjustment to compensate for that.

Now, why on earth not just enable the 50R termination in the scope (or add an external one) and get the full precision of your expensive test equipment?? (And a nice 10X multiplier as specified...)

And of course, the proof is in the pudding, so I attached an example of running a pulse into 50R and 1M

[rvalente]

Other than because of BNC isolation, why the majority of differential probes has banana jacks instead of bnc?

Using the Banana to BNC adapter brings problems in frequency response?

[Serpent10i]

They use banana because they want to have two equal paths so that the signals are as similar as possible and they can reject as much common mode noise as possible.  Remember these probes are measuring the difference between the two measurment points, not just one point and ground. Therefor instead of a center conductor and outer ground you want to have two similar conductors, making these a twisted pair is even better.

[rvalente]

They use banana because they want to have two equal paths so that the signals are as similar as possible and they can reject as much common mode noise as possible.  Remember these probes are measuring the difference between the two measurment points, not just one point and ground. Therefor instead of a center conductor and outer ground you want to have two similar conductors, making these a twisted pair is even better.

So basically, using a regular 100Mhz probe with a BNC to banana adapter would pretty much mess all the differential balance/symmetry?

[Serpent10i]

I'm not sure I understand your question, do you mean attaching a normal scope probe to the tips of the differential probes?

That would be a bad idea for several reasons, first off the scope probe would add a lot of extra cable in front of your measurement and that alone will add noise and lose signal fidelity, but lets say that you had a very very short one.

The specific coax cable used in scope probes center conductor has some resistance even on 1x mode (intentionally lossy, see Dave's video on 1x scope probes for more info), so your signals will be different between the outer conductor (normally ground) with nearly 0 resistance and the center with normally somewhere between a bit and a lot of resistance. They're also matched to the input of your specific scope, not matched for the input of whatever differential probe inputs you're using.

But lets assume that you're just using normal Coax cable with very low resistance and not matched for any specific scope input, this still isn't a great idea... As you suggested the wires being not being separately equal will also cause some signal issues, the outer shell will likely pickup more/different noise than the inner conductor leading to difference between signals and ones that will be measured/amplified by the differential probe.

tl;dr yes it's a problem, you should just use the banana cables with whatever tips you like

* BNC is the connector type, coaxial is the wire type with a single inner conductor and then an outer shell.

[tautech]

They use banana because they want to have two equal paths so that the signals are as similar as possible and they can reject as much common mode noise as possible.  Remember these probes are measuring the difference between the two measurment points, not just one point and ground. Therefor instead of a center conductor and outer ground you want to have two similar conductors, making these a twisted pair is even better.

So basically, using a regular 100Mhz probe with a BNC to banana adapter would pretty much mess all the differential balance/symmetry?

Yes, exactly.
If you need some sort of grabber with a differential probe, most are supplied with HV rated parrot beak grabbers.

[David Hess]

I'm not sure I understand your question, do you mean attaching a normal scope probe to the tips of the differential probes?

Early high voltage differential probes did exactly that with normal oscilloscope probes connected to a differential input vertical amplifier.

[rvalente]

I'm not sure I understand your question, do you mean attaching a normal scope probe to the tips of the differential probes?

I've asked because feels funny to me to imagine a 100MHz signal in a alligator clip with banana plugs, even if the cables are twisted.

But of course, your answer was spot on, tks mate