New low-cost ($170) 100MHz Differential scope probe from Micsig

[mk_]

...so I finally got around to cutting off ~20cm of lead length on one my DP10013 probes. I haven't done any proper measurements of the new frequency response after the mod, but it sure did make an improvement regarding ringing!

It is a well known secret that leads for oscilloscope-probes should be "resistive" wires for damping ringing. There is an old AN from Tektronix somewhere on the net which demostrates this. In the - also old - AN called "TekProbeCircuits" you can see some resistor in the signalpath for damping this ringing (Rs on p18, Fig. 2-10)

[Hydron]

Yes agreed - this (combined with the longer than usual length) is why some people including myself earlier in the thread were dubious about the design before anyone even did any measurements. But the price was right (even for the more accurate ~50MHz of bandwidth you get without the lead peaking) so I went for a couple anyway.

This issue is certainly not confined to the Micsig probe - most models of differential probe in this style have non-resistive leads, and I suspect the only reason they get away with it is that their response doesn't reach high enough to see the undamped ringing. There is a certain discontinued fluke model (DP-120?) that has resistive input leads forming part of the attenuation circuit but sadly it is limited to a fairly low 20MHz bandwidth.

[mk_]

Yes agreed - this (combined with the longer than usual length) is why some people including myself earlier in the thread were dubious about the design before anyone even did any measurements. But the price was right (even for the more accurate ~50MHz of bandwidth you get without the lead peaking) so I went for a couple anyway.

This issue is certainly not confined to the Micsig probe - most models of differential probe in this style have non-resistive leads, and I suspect the only reason they get away with it is that their response doesn't reach high enough to see the undamped ringing. There is a certain discontinued fluke model (DP-120?) that has resistive input leads forming part of the attenuation circuit but sadly it is limited to a fairly low 20MHz bandwidth.

Switching from 0 to 600V in 30-40ns results in a lot of ringing with the original leads at my Testec SI 9110 (1:100(0), 100Mhz, 1,4kV)  so I replaced those leads with some from a broken Tek. It`s a filigrane construction but anyway... bandwith remaind the same but no more ringing.

[nctnico]

From my own measurements it seems that the DP10013 works best with the original lead lengths. I assume MicSig factored in the capacitance between the leads (when twisted) into the frequency response.

[SteveyG]

I missed this thread 

I posted a video recently about this differential probe and will be using it in some upcoming videos, but I did want to comment that having used this on my bench for the past week or so it actually works really well and in my opinion can't be beaten in terms of value for money.

https://www.banggood.com/custlink/33G3Jmr8bC
Coupon code: "aff7off" brings it down to around £120 delivered, which IMO is a bargain

Here's my video if anyone is interested:
https://youtu.be/dzeK3Nm3N44

[frozenfrogz]

You do not need to go through the trouble of importing from China. Buy via ebay.co.uk from Germany for less than £100 delivered.

[SteveyG]

Doesn't show up for me anything like that on ebay for the UK. Thanks for the info though 

[frozenfrogz]

Doesn't show up for me anything like that on ebay for the UK. Thanks for the info though 

https://www.ebay.co.uk/itm/New-1300V-Oscilloscope-100MHz-Differential-Probe-Kit-Micsig-DP10013-EL/143093519228

Postage from UK

[SteveyG]

They're a bit naughty with the listing, it's being shipped from Singapore to the UK warehouse then on to you to avoid customs charges.

[frozenfrogz]

They're a bit naughty with the listing, it's being shipped from Singapore to the UK warehouse then on to you to avoid customs charges.

Well sure, this was just the first listing I found, when switching my "location" to UK. Anyway, all those devices somehow have to make their way from China to the EU (or thereabout xD) and as long as the seller takes care of that, it is fine with me - it is still 110 € delivered without having to deal with DHL Express / customs / ...
I have been prancing around one of these for quite some time and now seems a good time to finally buy one - thanks for reminding me.

Edit: On ebay.de there are a bunch of listings from the same seller. Same price, but the listing quotes "DP10013 EDQ", "DP10013 LY", "DP10013 EAv",... Are these just identifiers from the seller per listing or are there several different versions available? I am a bit confused. Micsig website does not help here. 

[SteveyG]

They're a bit naughty with the listing, it's being shipped from Singapore to the UK warehouse then on to you to avoid customs charges.

Well sure, this was just the first listing I found, when switching my "location" to UK. Anyway, all those devices somehow have to make their way from China to the EU (or thereabout xD) and as long as the seller takes care of that, it is fine with me - it is still 110 € delivered without having to deal with DHL Express / customs / ...
I have been prancing around one of these for quite some time and now seems a good time to finally buy one - thanks for reminding me.

Edit: On ebay.de there are a bunch of listings from the same seller. Same price, but the listing quotes "DP10013 EDQ", "DP10013 LY", "DP10013 EAv",... Are these just identifiers from the seller per listing or are there several different versions available? I am a bit confused. Micsig website does not help here.

I think those are nothing to do with the part numbers, just some weird thing the person listing it is doing. I quite like using Banggood as they also deal with the import duty and actually sort out any problems with an order.

[MiroS]

I quite like using Banggood as they also deal with the import duty and actually sort out any problems with an order.

I do not think that this 'like'  can justify 30 USD more  or so   Especially that this maybe 30 usd more on  top of custom  and VAT.

[Housedad]

I'm going to try adding resistors to the leads and see what happens with my MSIG probe.  I was reading about this on the Keysight paper http://literature.cdn.keysight.com/litweb/pdf/5992-2848EN.pdf  Starting on page 8.

[joesmith]

I missed this thread 

I posted a video recently about this differential probe and will be using it in some upcoming videos, but I did want to comment that having used this on my bench for the past week or so it actually works really well and in my opinion can't be beaten in terms of value for money.

https://www.banggood.com/custlink/33G3Jmr8bC
Coupon code: "aff7off" brings it down to around £120 delivered, which IMO is a bargain

Here's my video if anyone is interested:
https://youtu.be/dzeK3Nm3N44

This looks really nice

[exe]

I quite like using Banggood as they also deal with the import duty and actually sort out any problems with an order.

Are you sure about this? Last time I used banggood (about 2 years ago or so) it was explicitly mentioned that import tax and duties are on the buyer. They even used to have "tariff insurance": https://blog.banggood.com/banggood-tariff-insurance-61604.html .Also, I see they say explicitly on their website that they do not manager import taxes and duties: https://www.banggood.com/Taxes-and-tariffs_hl69_at310

[SteveyG]

I quite like using Banggood as they also deal with the import duty and actually sort out any problems with an order.

Are you sure about this? Last time I used banggood (about 2 years ago or so) it was explicitly mentioned that import tax and duties are on the buyer. They even used to have "tariff insurance": https://blog.banggood.com/banggood-tariff-insurance-61604.html .Also, I see they say explicitly on their website that they do not manager import taxes and duties: https://www.banggood.com/Taxes-and-tariffs_hl69_at310

Any order over the duty threshold with the insurance appears to go to a warehouse just near Heathrow Airport, and is then delivered by Yodel as a UK shipment. They have to put the warning on the website though I would assume.

If you use the link: https://www.banggood.com/custlink/33G3Jmr8bC Banggood have offered the discount code "DP10013" to drop the price to $139.99 delivered.

[BravoV]

If you use the link: https://www.banggood.com/custlink/33G3Jmr8bC Banggood have offered the discount code "DP10013" to drop the price to $139.99 delivered.

Actually you can get < $130 s/h included at Aliexpress with shop that sold many of it with good many feedbacks too, just fyi.

[SteveyG]

If anyone is interested, you can see the innards of the DP20003 in this short video. Micsig have increased the quality of the accessories in all new models so worth checking if it's new stock if you happen to order:

[mnsergey]

Today came to me the same, only high-voltage DP20003 from the company Micsig. Multipliers X200 and X2000 and maximum voltages, respectively 560V / 5600V. Quickly checked parameters give Rice Time ~ 10nS (against the stated 3.5 nS) and a frequency range of up to 25MHz on the AFC drop (-3dB) (against the stated 100MHz). So the Chinese are lying, the real delay is three times worse than the stated Rise Time parameter.
And this does not seem to be an isolated case, but a a deceptive business put on stream.
Just a week ago I'm received from  a current probe of the upper model Micsig CP2100B(2.5 MHz/175nsec) at a price of ~ $ 360. Promised a delay of less than 175nsec. As a result, after the tests, I got a delay of more than 450nsec, which is in fact the Junior CP2100A model with a price of about $165.
In the last case, a dispute was opened with the seller, and the device had to be sent to China as not meeting the stated parameters.
To say that I am angry, -  is  say nothing.
All such stories happen in the world, dear community...

[TopLoser]

Today came to me the same, only high-voltage DP20003 from the company Micsig. Multipliers X200 and X2000 and maximum voltages, respectively 560V / 5600V. Quickly checked parameters give Rice Time ~ 10nS (against the stated 3.5 nS) and a frequency range of up to 25MHz on the AFC drop (-3dB) (against the stated 100MHz). So the Chinese are lying, the real delay is three times worse than the stated Rise Time parameter.

I'm pretty sure people are going to suggest the probing setup in your photo is going to need a bit of improvement to show those kind of risetimes...

[TK]

Try twisting the red and black wires several turns and see if it improves the signal rise time

[briangordon]

I'm kind of concerned about powering it via the oscilloscope's USB port. I assume that the USB port on the scope is going to be tied to chassis ground and the USB power is going to be referenced to that as well. So is it really safe to measure a DUT that's powered by mains? Is the micsig probe's power input sufficiently isolated for this?

[2N3055]

I'm kind of concerned about powering it via the oscilloscope's USB port. I assume that the USB port on the scope is going to be tied to chassis ground and the USB power is going to be referenced to that as well. So is it really safe to measure a DUT that's powered by mains? Is the micsig probe's power input sufficiently isolated for this?

BNC output is allready connected to scope ground. Actually it is how it works in these types of probes. You have two inputs, both referenced to scope ground and you measure difference between them and convert it to single ended output.
Inputs are not floating with infinite resistance towards ground. They both have some high impedance path to ground, specified in manual.

[boB]

Old and ongoing thread, I know...

We have several of these Micsig differential probes (50X  500X) and  a lot of them eventually develop a DC offset.   You are supposed to be able to calibrate out this offset by holding down the 50X  and  500X  buttons for a moment while having the input leads shorted together.    This never works, at last for the sometimes large offset that we see.  I think the little processor may do the offset-null by injecting another offset into the last op-amp circuit...

I like Dave's video on this but however this works is left for the viewer to finish. 

I wonder if anyone here has ran into this issue and what you did to fix it ?

Thanks,
boB

[2N3055]

Old and ongoing thread, I know...

We have several of these Micsig differential probes (50X  500X) and  a lot of them eventually develop a DC offset.   You are supposed to be able to calibrate out this offset by holding down the 50X  and  500X  buttons for a moment while having the input leads shorted together.    This never works, at last for the sometimes large offset that we see.  I think the little processor may do the offset-null by injecting another offset into the last op-amp circuit...

I like Dave's video on this but however this works is left for the viewer to finish. 

I wonder if anyone here has ran into this issue and what you did to fix it ?

Thanks,
boB

That is interesting. Would you mind elaborating how much of the offset we are talking about here?
Thanks!