First oscilloscope

[Chrishas]

Hi, I've started going into electronics and as I'm reading a book called "Basic Electronics: Theory and Practice" one of the tools used is a scope. I'd like to do some audio projects in the future such as pedals and synth modules and also learn to repair stuff. I've been browsing ebay but a lot of the scopes I see here(uk) seem barely tested, there's barely any info about some brands/ models and in general hard to tell if sth is worth it. ie theres a hitachi v555(50MHz) for £95 but not sure how old it is, is it worth it over some hameg hm205-2 or 203-5? I'm trying to avoid anything missing probes, or which they don't have at least a couple pictures of it working.

Apologies if this seems vague but I see a lot of different opinions in different posts/forums. For example 20Mhz or less isnt good for some stuff, or if a scope is too old it may require a lot of time in repairs.

Thanks in advance for any info,
Chris

[ataradov]

There are a ton of threads on this topic. With varying opinions on whether analog scopes are useful anymore. No matter what you do, in modern days you will face digital signals, for which you would want to have a DSO.

I would add a bit more money and get a cheaper digital scope. There are a ton of decent options starting from $250 and even less in some cases.

As far as the probes go - they are a wear item and supposed to be replaced. Probes you will get with 30 year old scope are going to be garbage and will need replacement anyway. And really good probes are now really cheap that it is not really worth worrying about.

[george.b]

Hello, and welcome to the forum.

The HM205-2 is a combiscope with a 5MSa/s digitizer, which should suffice for capturing audio waveforms, but not much else. Both Hamegs have 20 MHz (analog) bandwidth, which is plenty for audio.
The Hitachi has cursors, which are a useful thing to have, not to mention way higher bandwidth, but it doesn't allow you to freeze a waveform on the screen.
The HM203-5 has, IMO, no redeeming features in comparison to the other two. The component tester seems like a gimmick to me.

It depends on which feature set you think will serve you better.

If you can go for a modern DSO, do that instead.

[james_s]

The Hitachi scopes are fairly nice for the era. I would not bother with a 20MHz analog scope unless somebody offers it to you for free. It's better than nothing, but it's not worth what it would cost to ship, unless you're really going for the nostalgia aspect.

[rstofer]

Search for Charlotte.  We had a LONG thread a couple of weeks ago.  People’s opinions won’t have changed.  She’s in Switzerland,

[Wallace Gasiewicz]

Chris:
I do not know much about prices in UK. I had a real nice "school" Tek scope a few years ago. It was only 15 Megs but had a big screen and was very good at low audio freq.
I sold it for maybe $20. Cannot keep everything. (I suppose I'll be kicked out of TE anonymous for that last statement)

Wally

[akimpowerscr]

Hello and welcome to the forum.

We went to the moon thanks to analog oscilloscopes and suddenly it seems that an analog oscilloscope is no longer of any use, not even for a beginner. 

You say what you want to do:

"I'd like to do some audio projects in the future such as pedals and synth modules and also learn to repair stuff."

An analog oscilloscope is fine for what you want to do, maybe better than a DSO because it is easier to use and the component tester is very useful for repair.

But there are pitfalls to avoid:

- only buy an oscilloscope in good working order, never a broken device.

- buy only a simple oscilloscope, without cursor, without readout, and without excessive sophistication.
More sophisticated it is, more risk of failure.

- Give preference to oscilloscopes with component tester, it is very useful in repair.

For the probes, it is mainly wear accessories, it is better to buy new ones.

We find 60 or 100Mhz probes on ebay for a few tens of euros.

The price of analog oscilloscopes is often less than the price of repairing any device and allows you to take the risk of a possible breakdown ... In this case, the device is sold as defective and we buy another one .... the harm is very low.

What are my recommendations?

HAMEG: Made simple and rugged oscilloscopes in the past often with a built-in component tester.

The best choice in my opinion is the HM605 (60Mhz with component tester) but it becomes hard to find in good working order.
- HM 203: highly recommended (all versions)
- HM204: all versions
Avoid HM3XXs and newer HAMEG's, they are not very reliable.

TEKTRONIX: the most famous manufacturer of analog oscilloscopes:
I recommend the 465B (100Mhz) provided it is in good working order.
Also the 2235 although the 22xx series is less robust than the 465. (Mostly problems with power supply.)

Finally, why not mention it despite being rare, the Hewlett Packard HP1740A which is splendid but takes up a lot of space on the table. It must also be in perfect working order.

[HB9EVI]

We went to the moon thanks to analog oscilloscopes and suddenly it seems that an analog oscilloscope is no longer of any use, not even for a beginner. 

the 'better' is the enemy of the 'good'

It took myself a while till I was ready to go into DSOs; the final exitus of my Tek2230 was the punch over the line, and I never regretted it.
If it's turning about a recommendation for beginners, I start to think if it's really a good idea advising the purchase of old hardware.

That's not so much a question, if those devices are still valuable - certainly they are - BUT a newbie has practically no chance of fixing one of those older scopes, even if nobody doubts the quality of an old Tek or Hameg - they still can fail. Then what? If there's nobody at hand who can help out repairing for a convenient price it's turning in a 100% lost for the owner + frustration.

[akimpowerscr]

the 'better' is the enemy of the 'good'

The better is not the most sophisticated, it is the tool that is making what you need to do and that is simple to use.

For repair or for audio projects, a DSO is far too sofisticated, too much useless options....

Why obsess over failures? The risk is low, there are simple model analog oscilloscopes (not TEK 2465 .... !!) which have been working for decades without failure and which will certainly work for another ten years.

The problem is that on the forums we only talk about broken oscilloscopes, not about the thousands of others which continue to function perfectly.

[HB9EVI]

that's your point of view

a DSO is as intuitive to operate as an old fashioned CRO; the software featured addons can be used but they don't have to; maybe once you're glad to have a basic FFT function or an averaging; it can also help you out as a quite accurate frequency counter aso...

unless it's a real bargain and not a big loss in case of a final defect, there is no reason to still recommend CROs for beginners.

personally I was getting tired repairing my old hardware, never mind if test equipment or ham radios; and even if you repair it, nobody can assure that a Tek from the 80' is going to run another 10 years. I threw out my old Teks and Hamegs, also the good old FT-736; I really got tired of struggling ever and ever again in a new mess when I just wanted to do something else.
If you spend more time maintaining your equipment than working on your projects, something is wrong. Maybe I've had an unlucky hand with my vintage devices, but since they're gone, I have time doing that what I want and spend much less time troubleshooting my working horses.

[rsjsouza]

the 'better' is the enemy of the 'good'

The better is not the most sophisticated, it is the tool that is making what you need to do and that is simple to use.

For repair or for audio projects, a DSO is far too sofisticated, too much useless options....

Why obsess over failures? The risk is low, there are simple model analog oscilloscopes (not TEK 2465 .... !!) which have been working for decades without failure and which will certainly work for another ten years.

The problem is that on the forums we only talk about broken oscilloscopes, not about the thousands of others which continue to function perfectly.

Well, depends on the audio. Digital audio (more and more proeminent these days) can greatly benefit from the DSO "useless" features. Repair of car radios can also be made more difficult if you have one of these digital amplifiers tightly coupled with the main MCU. Vaccuum tube audio usually benefits from the higher input voltage tolerance of much older oscilloscopes (equally made with vaccuum tubes) but a great deal of repairs require just signal tracing, which can be made using other methods. This is far from a comprehensive list of "audio" applications, but it is broad enough that it can't be put under the same umbrella.

Regarding the years of use of an older oscilloscope: sure, they have been working for years now but there is always a tradeoff between repairability (harder on a more modern oscilloscope) versus chances of actually needing the repair (higher on an old oscilloscope).

IMO, I also am on the field of the first three responders: preferrably go for a new DSO due to the longer usability in the field, or get an old analog oscilloscope if it works and can be had for very minimal price. Another alternative is if you can find a used Rigol DS1052E or DS1102E in pristine condition for relatively low money (maybe $100, but that depends on the used market) - these lack the added features of more modern DSOs but are very well built and very usable.

[rstofer]

If you scour eBay for scopes, and there are hundreds, watch out for shipping.  It is very likely that the shipping is as much or more than the scope.

I really recommend reading ALL of Charlotte's thread because every conceivable argument is made, over and over.  It's not until Reply 150 that she goes all in on a 200 MHz 2 Channel Siglent SDS 1202X-E which is an excellent choice.

https://www.eevblog.com/forum/beginners/what-an-oscilloscope-recommended-for-a-woman-passionate-about-electronics/150/

There a lot of discussion leading up to that point.

But the real fun starts AFTER she buys the Siglent and works through the User Manual, point by point.  The thread is a long read but there are some really useful experiments.  Many of the experiments simply can't be done on an analog scope.  FFT, Integration, Measurements, Single Shot and so on.  These features belong to the DSO.

[george.b]

- Give preference to oscilloscopes with component tester, it is very useful in repair.

Again - gimmick feature. Functionality that can be replicated externally for pennies with an old transformer and a couple of components shouldn't be considered as a selection criterion for an oscilloscope.

[akimpowerscr]

a DSO is as intuitive to operate as an old fashioned CRO;

This is not true at all.

Compare the simplicity of the controls of an HM203 with all of the menus and submenus of a DSO.

A DSO is not intuitive at all .... You have to spend days studying the manual while on an analog oscilloscope, there is almost nothing to learn to be able to use it.

An example: the trigger options of a DSO: a real headache for a beginner.

[akimpowerscr]

Again - gimmick feature. Functionality that can be replicated externally for pennies with an old transformer and a couple of components shouldn't be considered as a selection criterion for an oscilloscope.

The fact that the component tester is integrated into the oscilloscope is a great advantage ...
No need to disconnect the probes and plug in the BNC cables from the external device.

In addition, DSO's do not work well in XY

[wizard69]

As already mentioned lots of great threads on this subject.    In simple terms any scope is netter than no scope!!!!   For audio work there is no reason not to use and analog scope.   The trick is to buy a working unit.

Hi, I've started going into electronics and as I'm reading a book called "Basic Electronics: Theory and Practice" one of the tools used is a scope. I'd like to do some audio projects in the future such as pedals and synth modules and also learn to repair stuff.

If you intend to work on digital based synths, then you "might" need a higher end modern scope.    I'm of the opinion though that you don't need a high end and expensive scope to get started in audio work.   

 I've been browsing ebay but a lot of the scopes I see here(uk) seem barely tested, there's barely any info about some brands/ models and in general hard to tell if sth is worth it. ie theres a hitachi v555(50MHz) for £95 but not sure how old it is, is it worth it over some hameg hm205-2 or 203-5?

I'm trying to convert that to Yankee bucks but I have to think that 95 is a bit high for that era scope.  Hitachi made decent scopes so if it is in good condition it might be worth it.

I'm trying to avoid anything missing probes, or which they don't have at least a couple pictures of it working.

I believe you are holding probes to a standard they are not worthy of.   Consider any probes supplied with a used instruments as garbage until proven otherwise.   Probes of all types are wear items and need to be inspected regularly and replaced as needed.    Inspection should be at every use if you get involved in high voltage work, I always give my probes a quick review at work when working on high voltage stuff.   It is very much a save your ass practice.

Frankly you often see people in the industry being foolish about probes.    I'm not sure why this attitude exists because probes are relatively cheap and frankly are of higher quality than most of the old stuff out there.   Even with audio work safety needs to be considered!

Apologies if this seems vague but I see a lot of different opinions in different posts/forums. For example 20Mhz or less isnt good for some stuff, or if a scope is too old it may require a lot of time in repairs.

The interesting thing about repairs is that they are also learning opportunities.   Repairing a scope for a business or even a focused hobby might not make sense but as a way to expand your electronics repair experience fixing an analog scopes is a skills builder.   This assume you can get prints and the like for the scope.   Learning with out the prints is more of a struggle.

When considering bandwidth the first thing to realize is that you don't need a lot of bandwidth for audio work.   This especially when focused on the analog end of the business.   Now given that you are better off going well outside of the audio band.   For audio work you can even consider some of the USB based instruments.    USB based instruments like Analog Discovery generate a lot of opinions so that might be another discussion.

Thanks in advance for any info,
Chris

The trick when starting out is to find the right balance of dollar outlays.    Personally if you are about to buy something new, as a beginner, I'd go with a good quality bench multimeter.   This assumes that you can find a decent scope to get by with for a couple of years.    The reason is a good bench meter will beat out the best handheld meter you can buy as far as ease of use on an electronics work bench.   One handed operation and an easy to read screen are two of the bigger reasons to go with a bench DMM.   Also consider that bench multimeters have a range of functions that didn't even exists on bench meters in the 1970's.

Of course if you can't find a decent used scope you may have to apply more of you budget to a new scope.   You don't want to be without one.    It is just that I don't like using handheld DMM on the work bench.   
 

[akimpowerscr]

I would like to add some information that might be useful.

For the repair of analog synthesizers, it is sometimes necessary to adjust the frequency of oscillators.

We could do this by using a function generator with digital reading and using the XY fonction of the oscilloscope.

With the Lissajous pattern, you can get a precise adjustment but it is quite touchy for frequencies of 1Khz and higher.

Another method would be to use an inexpensive vintage frequency counter or a cheap kit from ebay.

I use an old HP5315A ... The frequency counter does not need to have high accuracy or a high frequency bandwith.

One advantage that the HM204 has over the HM203 is that it has a Y output on the rear panel.

This makes it possible to connect the frequency counter to it and to be able to constantly read the frequency of the signal displayed on the screen.

[nigelwright7557]

I have got by with a 20MHz analogue scope for about 10 years now in my own business.
I designed stuff upto about 20MHz so its fine for that.
I do a lot of audio and that is we  lwithin its limits.
Paid £40 off ebay for it as its second channel isnt working properly.

You really need to think about what you are going to use a scope for.
Thats will give yo ua bandwidth and scope type to go for.

My sig gen is about 10 years old to oand paid £20 for that on ebay.

Fancy soldering station ? No, £10 soldering iron from Maplin that goes on forever and a tip lasts about a year.

[HB9EVI]

a DSO is as intuitive to operate as an old fashioned CRO;

This is not true at all.

Compare the simplicity of the controls of an HM203 with all of the menus and submenus of a DSO.

A DSO is not intuitive at all .... You have to spend days studying the manual while on an analog oscilloscope, there is almost nothing to learn to be able to use it.

An example: the trigger options of a DSO: a real headache for a beginner.

again, that's your point of view

except for the specs, I never really bothered even taking a look into the manual

if you talk about the trigger options, you already talk about something, what a classical CRO doesn't even have - more than an edge trigger you don't get there, and even on the DSO as a standard setting I use most of the time that type of trigger.

the way you talk, one might have the impression you never really bothered trying out a DSO

[pwlps]

I had many analog scopes and liked them but I switched to DSOs when I realized how useful it can be to see the signal before the trigger.

PS. At the time they appeared I remember I was very impressed by this apparent causality violation in DSOs, today none of my students has ever asked about how it works 

[akimpowerscr]

again, that's your point of view

except for the specs, I never really bothered even taking a look into the manual

if you talk about the trigger options, you already talk about something, what a classical CRO doesn't even have - more than an edge trigger you don't get there, and even on the DSO as a standard setting I use most of the time that type of trigger.

the way you talk, one might have the impression you never really bothered trying out a DSO

I don't think you can put yourself back in the place of a beginner.

Follow RSTOFER's advice and read the 32 pages of Charlotte's topic which masterfully demonstrates the difficulties a beginner encounters with a DSO

[akimpowerscr]

I had many analog scopes and liked them but I switched to DSOs when I realized how useful it can be to see the signal before the trigger.
......

Totally useless to learn basic electronics and "to do some audio projects in the future such as pedals and synth modules and also learn to repair stuff;"

[pwlps]

Totally useless to learn basic electronics and "to do some audio projects in the future such as pedals and synth modules and also learn to repair stuff;"

Possibly yes, still, it is not useless to know about it. And in "repair stuff" it might be useful depending on the "stuff" in question

[HB9EVI]

I don't think you can put yourself back in the place of a beginner.

Follow RSTOFER's advice and read the 32 pages of Charlotte's topic which masterfully demonstrates the difficulties a beginner encounters with a DSO

I followed that topic for a while; I guess you should be able to admit, that the aptitude to get into a new matter, heavily depends on the individual learning curve. Charlotte wanted to progress quite fast, understanding the things also on the basic physical-mathematical level and not only reduced on the operation of the device itself. From my point of view that's the way it should go.

also I have to say, that the limited digital capabilities of my old Tek2230 were trickier to understand and use in meaningful way than it ever was on my DSOs.

still:

if one can get hands on a CRO for a few bucks, sure, why not? but I consider it useless to spend 100s of bucks for a state-of-the-art CRO from 1975 and then end up in disappointment, if something on that device is going to fail. I got already too often in conversations with other hams, who bought old gears and ended up with a lot of frustration, if those beauties stopped working. No newbie is able to fix more than a few basic things, not even on an old analog CRO from the 70ies. Not to talk about, that I have a bad feeling seeing beginners pick in a CRO maybe not being aware, where to better leave the fingers out due to high voltage.

[CharlotteSwiss]

I cannot make a comparison between digital and analog oscilloscope (never used an analog); I can however say that the digital one really performs many functions, maybe even too many! But with patience and studying the manual well you learn everything; in my spare time I have been studying my siglent 1202 for more than 3 months, now I am at the end of the study and I have learned almost all its potential; to solve some problems it gives you more possibilities, but if you don't study them all you will always use the usual ones without going further.
As a beginner I had quite a hard time learning all the functions, some I understood immediately others it took me weeks (the difficult ones are all analyzed in my topic).
For the choice of a DSO I would recommend brands like siglent or rigol, they make good products at human prices; the first thing you will have to face will be what bandwidth you might need and especially if you need 4 channels, in my topic this aspect is analyzed in the first pages ..
Good choice!

[wizard69]

Nigel has some good points here!!!    You don't need a lot of capability for audio work.   Further there are tons of used equipment out there that is more than good enough.   The last thing you want to do, be it a business or hobby, is to burn a lot of cash on instruments and lab setup.   The trick is knowing what you need and where to get it.

I have got by with a 20MHz analogue scope for about 10 years now in my own business.
I designed stuff upto about 20MHz so its fine for that.
I do a lot of audio and that is we  lwithin its limits.
Paid £40 off ebay for it as its second channel isnt working properly.

You really need to think about what you are going to use a scope for.
Thats will give yo ua bandwidth and scope type to go for.

My sig gen is about 10 years old to oand paid £20 for that on ebay.

Fancy soldering station ? No, £10 soldering iron from Maplin that goes on forever and a tip lasts about a year.

[No.Mad]

Hi Chris,

Two models you pointed out are quite good for any starting hobbyist, but I wouldn't recommend for repairing stuff as bandwidth sometimes could be insufficient.

There are few problems with older scopes: obsolete or proprietary parts, mostly uses CRT displays which use high voltage and when it's gone, it's gone.
Advantage of older scope is surely service manual available in pdf that you could download from net and high reparability - even after considering obsolete parts.

Try to look around on forum searching for models you are interested in, there should be at least one post with review

On side note: I have unused GW Instek GDS-1052U oscilloscope, 50MHz, 250MSps. It sits in box, collecting dust as I upgraded to older Agilent MSO (I needed higher bandwidth and digital probe in scope). It has everything original, in perfect working condition and in small size. I could sell it to you for £200+P. Hit me PM if you are interested.

Regards,
No.Mad

[rstofer]

Nigel has some good points here!!!    You don't need a lot of capability for audio work.

As long as audio is the end game, bandwidth isn't really important as long as it is somewhat more than the audio spectrum - up to about 20 kHz.  But there may be some high frequency oscillations that need to be seen to be dealt with.  10 MHz will show these oscillations in most cases.

But just as soon as you hit digital, bandwidth requirements increase; quickly.  I have a DS1054Z unlocked for 100 MHz operation.  The other day I was looking at a clock signal generated by an FPGA project.  I wanted to be certain it was the proper frequency so I planned to use the scope's internal frequency counter.  This worked fine and measured about 60 MHz, as I expected.

But the waveform looked like a distorted sine wave.  Well, duh!  The square wave would be composed of the odd harmonics of 60 MHz so the 3rd harmonic would be around 180 MHz, the 5th around 300 MHz and the 7th around 420 MHz and, in my view, a square wave doesn't look good without at least the 9th harmonic, possibly more.  My poor little 100 MHz scope was totally inadequate.  Even my 350 MHz Tek 485 would only display up to the 5th harmonic.  I would need a 500 MHz scope to get a reasonable representation.

Had I bought the 200 MHz Siglent I have been lusting over, it might have been able to display the fundamental plus the 3rd harmonic - still inadequate if I were trying to look at signal integrity.

Fortunately, all I cared about was the frequency of the waveform, not the waveform display.

In my view, these low bandwidth analog scopes are useless for modern digital projects.  That's why I got rid of my 10 MHz Heathkit scope and moved to the 350 MHz Tek.

An FPGA output at 60+ MHz is unusual for me.  I am normally working at 10 MHz and below for things like SPI.  As a result, my 100 MHz scope will display the 9th harmonic and that 200 MHz Siglent would be even better.

So, if the goal is to stay forever and always in the audio spectrum, almost any scope is good enough.  But just as soon as you start playing in the digital sandbox, bandwidth requirements explode.

https://www.mathworks.com/help/matlab/math/square-wave-from-sine-waves.html

The real spec to worry about is the scope's risetime.  But this is tied to the bandwidth on the nameplate by a constant of 0.35 so, if you have have the bandwidth, you will have the risetime and vice versa.  Any discussion of 'equivalent time sampling' is omitted...  It's just voodoo and requires a repetitive signal.

RT = 0.35 / BW  where RT (risetime) is in nanoseconds and BW (bandwidth) is in gigahertz.  For 100 MHz you get RT = 0.35 / 0.1 = 3.5 ns.  Check your scope manual and see what you find.

[akimpowerscr]

you forget to mention something very important! probing frequencies of 200 and more Mhz is not as simple as you seem to present it.

In the past, Tektronix made all is input amplifiers with bandwith higher than 200Mhz only with 50R input resistance.

There was a good reason for this: to probe high frequencies is quite difficult : you need an expensive active probe to not disturb the circuit you are probing.

Passive probe have a too large input capacitance, which mean a very low impedance at high frequencies.

So, for a beginner, and even for an hobbiest, bandwith of 350Mhz does not matter....

It's like to buy a car with maximum speed of 250 Km/h when you live in a country where speed is limited to 120Km/h !!!!

[george.b]

you forget to mention something very important! probing frequencies of 200 and more Mhz is not as simple as you seem to present it.

In the past, Tektronix made all is input amplifiers with bandwith higher than 200Mhz only with 50R input resistance.

There was a good reason for this: to probe high frequencies is quite difficult : you need an expensive active probe to not disturb the circuit you are probing.

Passive probe have a too large input capacitance, which mean a very low impedance at high frequencies.

So, for a beginner, and even for an hobbiest, bandwith of 350Mhz does not matter....

It's like to buy a car with maximum speed of 250 Km/h when you live in a country where speed is limited to 120Km/h !!!!

Umm... no. As hinted by rstofer, if you're measuring a square wave at, say, 50MHz, which is well within the domain of hobbyists, then to get a remotely passable representation of it, you'll need at least 250MHz bandwidth. Passive 10Mohm, 500MHz bandwidth probes do exist, so yeah. Dunno what you're going on about.

Also:

I would like to add some information that might be useful.

For the repair of analog synthesizers, it is sometimes necessary to adjust the frequency of oscillators.

We could do this by using a function generator with digital reading and using the XY fonction of the oscilloscope.

With the Lissajous pattern, you can get a precise adjustment but it is quite touchy for frequencies of 1Khz and higher.

Another method would be to use an inexpensive vintage frequency counter or a cheap kit from ebay.

I use an old HP5315A ... The frequency counter does not need to have high accuracy or a high frequency bandwith.

One advantage that the HM204 has over the HM203 is that it has a Y output on the rear panel.

This makes it possible to connect the frequency counter to it and to be able to constantly read the frequency of the signal displayed on the screen.

Or just get a DSO, which will show you the frequency of the signal displayed on the screen without need for other equipment?

[akimpowerscr]

Let's see for example :
N2873A Passive Probe, 10:1, 500 MHz, 1.3 m

Key Features & Specifications
500 MHz bandwidth
10:1 attenuation ratio
9.5 pF input capacitance
10 MΩ input resistance (when terminated into 1 MΩ scope input)
400 V CAT I and 300 V CAT II maximum input voltage
Scope compensation range: 10 – 25 pF

At 350Mhz, 9.5 pf has an impedance of 47.9R.....When probing, you are disturbing the circuit with a capacitive impedance of 47.9R at 350 Mhz and this may change the thrue waveform.

This is the reason why it is recomanded to use active probe to probe such high frequencies.

Umm... no. As hinted by rstofer, if you're measuring a square wave at, say, 50MHz, which is well within the domain of hobbyists, then to get a remotely passable representation of it, you'll need at least 250MHz bandwidth. Passive 10Mohm, 500MHz bandwidth probes do exist, so yeah. Dunno what you're going on about.

Really ?

As hobbyist you often need to measure the risetime of a 50Mhz square wave ?
For sure, you have to spend your time in a very specialized field of electronics .....

[rstofer]

As hobbyist you often need to measure the risetime of a 50Mhz square wave ?
For sure, you have to spend your time in a very specialized field of electronics .....

These days there is nothing specialized about a Digilent Basys3 FPGA board with an onboard oscillator running at 100 MHz.  The 60 MHz was created by an internal clock circuit and reduces the 100 MHz input to 60 MHz for internal use.  Believe me, there is nothing sophisticated about this.  If it were, I wouldn't be working on it.

But, as I said, I wasn't interested in the waveform for this particular application, I wanted to verify the frequency.  Seeing the waveform just reinforced how limited my scope actually is.  OTOH, I can't afford a 500 MHz DSO so what I see is what I get.  It's just a hobby and only 1 of several.

There's quite a difference between a 10 MHz analog scope and a 100 MHz DSO.  Just in terms of 9th harmonic values, the 10 MHz scope is limited to around 1 MHz while the 100 MHz DSO is limited to around 10 MHz.  There are signals all over the uC world that are in excess of 1 MHz but not so many that are higher than 10 MHz.  Sure, they exist and with these 600 MHz uCs they are becoming fairly common but, so far, they don't outrun my 350 MHz Tek 485.  But they will...

Again, if the end game is just audio, ignore all these comments.  Almost any scope is good enough.  The problem I see is that the hobby tends to morph and the next thing you know, you're playing with an Arduino and lusting for the speed of a Teensy 4.1.  Or you decide to play with FPGAs...

[george.b]

Whether using a passive probe will introduce problems with capacitive loading or not depends on what you're measuring. It doesn't sound fair to me to dismiss a whole class of measuring apparatus because in some cases they may not suffice.

Really ?

As hobbyist you often need to measure the risetime of a 50Mhz square wave ?
For sure, you have to spend your time in a very specialized field of electronics .....

Yes, really. The year is 2020, and FPGAs, multi-hundred-MHz microcontrollers and other fairly high-speed digital electronics are not exactly far from the grasp of hobbyists anymore.

[james_s]

I have a 1GHz scope and the bandwidth is nice to have, but honestly I could get by with a 20MHz analog scope for 90% of what I use a scope for. Bandwidth is like money, you can never have too much, but how much you really "need" depends on your goals. IMO the only reason to consider an analog scope anymore is if you find one really cheap, and they do turn up. You might even find one for free, I've given and received a few of them over the years, some that worked just fine. Ultimately any scope that even mostly works is better than no scope at all, which is what I had for the first decade or so of my electronics hobby.

[jonslab]

Go with a DIY one

[Chrishas]

First of all thanks everyone for all the valuable information and taking the time to reply. I've been looking at the suggestions provided and Charlotte's thread has been very educational and I'm still going over all the info.
I also understand that my concern for probes was invalid.
I'm keeping an eye out for a good deal and so far I see Hamegs come up more often than other brands although most are HM203s and usually around £100.
There's a few Tektronix but the only one which I saw was tested was a TDS320 on an auction but it doesn't seem to have great reviews.
I've also seen a Goldstar 9020A for £25 which I may be able to checkout in person. What's the opinion on those and is it worth it in terms of reliability, reputation? This is much cheaper to what I've seen so far and with the location it's very tempting. If I did check it out what are some things to test on the spot?

[Mr. Scram]

Go with a DIY one

I did that and regretted it. I saw various things that started making sense after I bought a basic but "real" oscilloscope.

[george.b]

I'm keeping an eye out for a good deal and so far I see Hamegs come up more often than other brands although most are HM203s and usually around £100.
There's a few Tektronix but the only one which I saw was tested was a TDS320 on an auction but it doesn't seem to have great reviews.
I've also seen a Goldstar 9020A for £25 which I may be able to checkout in person. What's the opinion on those and is it worth it in terms of reliability, reputation? This is much cheaper to what I've seen so far and with the location it's very tempting. If I did check it out what are some things to test on the spot?

The TDS320 isn't a bad scope, if you can get it for cheap. It's a lot better than my first DSO (a Tek 2430A). It is old though, like all the options you present. It's got just 1k points acquisition memory, but meh, that's a lot more than none at all, and 500MSa/s isn't too shabby. It has some modern conveniences like automatic waveform measurements - no FFT, though.
I have a Leader-rebadged Goldstar, not a 9020A, but a similar 7020A. Its HV transformer failed; I found the whole thing kinda shoddily built overall. All phenolic single-sided board construction inside. £25 is alright, I think, if it's in good condition. I mean, it's still a real oscilloscope, albeit a basic one.
Be aware that any of them could work for many years or a couple of days before malfunctioning, and you may have to service it eventually.

Go with a DIY one

I did that and regretted it. I saw various things that started making sense after I bought a basic but "real" oscilloscope.

Those DIY scopes are little more than toys.

[james_s]

I've had a few TDS300 series scopes, they're decent instruments, just old. The thing to watch out for with them is the DS1644 which holds the calibration constants, I tried to back that up on two that I had and in both instances it got corrupted somehow and calibration costs more than the scope is worth generally. The TDS400 series is better in the regard that it stores the calibration in EEPROM but it's also quite an old instrument. Decent if you can get it cheap but a lot of times people ask inflated prices due to the Tek name.

[rsjsouza]

I've also seen a Goldstar 9020A for £25 which I may be able to checkout in person. What's the opinion on those and is it worth it in terms of reliability, reputation? This is much cheaper to what I've seen so far and with the location it's very tempting. If I did check it out what are some things to test on the spot?

The Goldstar you mentioned is one of the opportunities for a cheap and very basic oscilloscope. I would definitely schedule a visit and check it out.

Several common sense aspects to look for:
- see if the screen is in good shape and not slanted, has severe distiortions around a certain point. These could be signs of mistreatment that are affecring the tube.
- not a problem per se, but check if the waveforms are aligned with the horizontal axis. If not, then locate the rotation adjustment and see if you can put them horizontal. If you can't, this may be a sign of mistreatment on the tube or simply a failing circuit. This is usually good to see after the oscilloscope is on for 10+ minutes.
- If the scope has probes, plug each channel to the 1kHz square wave compensation output and check the output for frequency or amplitude deviations (you need to count divisions on the graticule). Rotate the various controls looking for mechanical jamming or lockups or electrical noise when rotating them. Pay special attention to the V/div and ms/div and see how the waveform (or just the GND signal) behaves.
- Do you have a multimeter with a built in signal generator or maybe a simple capacitance checker? If so, that is an interesting way to show a waveform that can go higher than 1kHz. Otherwise, assemble a small high frequency NAND oscillator (or use a crystal oscillator)  ircuit and see how the oscilloscope shows it. For a square wave, don't go over 3 or 5MHz.
- take a small battery where you know the voltage (using a DMM) and measure it with the oscilloscope. You can know its voltsge and if the AC mode is working (in this setting it should show zero volts)

Others may have additional tips. Good luck!