Looking for a good, cheap Analog Oscilloscope

Anything about hardware musical instruments.
Fox_GAMING_NTF
KVRist
225 posts since 11 Apr, 2019

Post Wed Nov 20, 2019 5:30 pm

I'm looking on eBay, and I'm wondering;
for old Analog Oscilloscopes, is 20MHz ok? What is a decent amount for today? I'm just trying to find a decent analog oscilloscope that I can get, mainly because I am in love with the cool CRT-Afterglow effect, and, it could probably be actually useful for me, maybe, too. Please keep in mind that I'm only 14, and also know pretty much nothing about oscilloscopes (I've only just started looking into them maybe an hour, ~hour 30 mins ago?)

Thanks in advance!

JCJR
KVRAF
2897 posts since 17 Apr, 2005 from S.E. TN

Re: Looking for a good, cheap Analog Oscilloscope

Post Wed Nov 20, 2019 6:33 pm

For just looking at audio frequencies 20MHz is good enough. Even 10 or maybe even 5 MHz could be good enough for fairly non critical audio frequency waveforms and eye candy.

Dual channel would be nicer than single channel. They get old. A $50 50 year old eBay scope might not work very well. Some of the new $400+ Chinese lunchbox digital scopes look like a lots better deal if you can't find what you want used for less than $100. But the little $50 new postage stamp Chinese scopes probably a complete waste of money.

The "20 MHz" for instance might typically mean that a clean 20 MHz square wave (which has harmonics going way above hundreds of megahertz) would look like an attenuated sine wave on the 20 MHz scope.

That is why it can give a pretty decent picture of audio up to 20 kHz or even signals up to 100 kHz, but the closer you get to 20 MHz you get, the more rounded off and unrealistic the signal image.

That is no problem for casual audio use. Just trying to explain if maybe you needed to get a fairly accurate picture of a 5 MHz digital pulse train (Maybe for debugging low speed digital logic) then you probably want at least a 100 or 200 MHz scope to get a pretty accurate picture of the 5 MHz pulse shape. It probably wouldn't be very useful to see something resembling a sine wave on a 20 MHz scope. In other words, looking at a 5 MHz pulse train on a 20 MHz scope, you really wouldn't know if it was a good crisp pulse wave or a rounded almost-sine wave because both a crisp or smooth 5 MHz signal would look about the same rounded mess on a 20 MHz scope.

Which doesn't matter for audio eye candy. Am just trying to explain.

There is a real good free vst scope plugin that would be more educational and better eye candy for looking at computer audio waves than an old analog scope.

I mean scopes are great, a nerd's best friend. What cheezy sci-fi movie would be complete without a scope and bubbling test tubes?

But they are mostly good for poking a probe into dissected electronic guts. There are various scope adapters you can hook to a laptop, but if I am gonna poke a probe into some random electronic gear I want to use a scope because that is what they are made for.

I would be real sad to hook up a 100 dollar scope adapter to a 2000 dollar computer, poke a probe the wrong place in a guitar amp and fry the 2000 dollar laptop. Sure you can fry a scope too if yer not careful, but at least a real scope is made for poking into the powered up guts of random gadgets.

But if all you want to do is look at computer waveforms then you don't need a scope. Even though scopes are even more funner than a bucket full of slide rules. :)

Fox_GAMING_NTF
KVRist
225 posts since 11 Apr, 2019

Re: Looking for a good, cheap Analog Oscilloscope

Post Thu Nov 21, 2019 3:27 am

JCJR wrote:
Wed Nov 20, 2019 6:33 pm
For just looking at audio frequencies 20MHz is good enough. Even 10 or maybe even 5 MHz could be good enough for fairly non critical audio frequency waveforms and eye candy.

Dual channel would be nicer than single channel. They get old. A $50 50 year old eBay scope might not work very well. Some of the new $400+ Chinese lunchbox digital scopes look like a lots better deal if you can't find what you want used for less than $100. But the little $50 new postage stamp Chinese scopes probably a complete waste of money.

The "20 MHz" for instance might typically mean that a clean 20 MHz square wave (which has harmonics going way above hundreds of megahertz) would look like an attenuated sine wave on the 20 MHz scope.

That is why it can give a pretty decent picture of audio up to 20 kHz or even signals up to 100 kHz, but the closer you get to 20 MHz you get, the more rounded off and unrealistic the signal image.

That is no problem for casual audio use. Just trying to explain if maybe you needed to get a fairly accurate picture of a 5 MHz digital pulse train (Maybe for debugging low speed digital logic) then you probably want at least a 100 or 200 MHz scope to get a pretty accurate picture of the 5 MHz pulse shape. It probably wouldn't be very useful to see something resembling a sine wave on a 20 MHz scope. In other words, looking at a 5 MHz pulse train on a 20 MHz scope, you really wouldn't know if it was a good crisp pulse wave or a rounded almost-sine wave because both a crisp or smooth 5 MHz signal would look about the same rounded mess on a 20 MHz scope.

Which doesn't matter for audio eye candy. Am just trying to explain.

There is a real good free vst scope plugin that would be more educational and better eye candy for looking at computer audio waves than an old analog scope.

I mean scopes are great, a nerd's best friend. What cheezy sci-fi movie would be complete without a scope and bubbling test tubes?

But they are mostly good for poking a probe into dissected electronic guts. There are various scope adapters you can hook to a laptop, but if I am gonna poke a probe into some random electronic gear I want to use a scope because that is what they are made for.

I would be real sad to hook up a 100 dollar scope adapter to a 2000 dollar computer, poke a probe the wrong place in a guitar amp and fry the 2000 dollar laptop. Sure you can fry a scope too if yer not careful, but at least a real scope is made for poking into the powered up guts of random gadgets.

But if all you want to do is look at computer waveforms then you don't need a scope. Even though scopes are even more funner than a bucket full of slide rules. :)
Oof, yeah, I'm going to probably be getting a Behringer Deepmind 12, So I don't know.

Fox_GAMING_NTF
KVRist
225 posts since 11 Apr, 2019

Re: Looking for a good, cheap Analog Oscilloscope

Post Thu Nov 21, 2019 3:28 am

JCJR wrote:
Wed Nov 20, 2019 6:33 pm
For just looking at audio frequencies 20MHz is good enough. Even 10 or maybe even 5 MHz could be good enough for fairly non critical audio frequency waveforms and eye candy.

Dual channel would be nicer than single channel. They get old. A $50 50 year old eBay scope might not work very well. Some of the new $400+ Chinese lunchbox digital scopes look like a lots better deal if you can't find what you want used for less than $100. But the little $50 new postage stamp Chinese scopes probably a complete waste of money.

The "20 MHz" for instance might typically mean that a clean 20 MHz square wave (which has harmonics going way above hundreds of megahertz) would look like an attenuated sine wave on the 20 MHz scope.

That is why it can give a pretty decent picture of audio up to 20 kHz or even signals up to 100 kHz, but the closer you get to 20 MHz you get, the more rounded off and unrealistic the signal image.

That is no problem for casual audio use. Just trying to explain if maybe you needed to get a fairly accurate picture of a 5 MHz digital pulse train (Maybe for debugging low speed digital logic) then you probably want at least a 100 or 200 MHz scope to get a pretty accurate picture of the 5 MHz pulse shape. It probably wouldn't be very useful to see something resembling a sine wave on a 20 MHz scope. In other words, looking at a 5 MHz pulse train on a 20 MHz scope, you really wouldn't know if it was a good crisp pulse wave or a rounded almost-sine wave because both a crisp or smooth 5 MHz signal would look about the same rounded mess on a 20 MHz scope.

Which doesn't matter for audio eye candy. Am just trying to explain.

There is a real good free vst scope plugin that would be more educational and better eye candy for looking at computer audio waves than an old analog scope.

I mean scopes are great, a nerd's best friend. What cheezy sci-fi movie would be complete without a scope and bubbling test tubes?

But they are mostly good for poking a probe into dissected electronic guts. There are various scope adapters you can hook to a laptop, but if I am gonna poke a probe into some random electronic gear I want to use a scope because that is what they are made for.

I would be real sad to hook up a 100 dollar scope adapter to a 2000 dollar computer, poke a probe the wrong place in a guitar amp and fry the 2000 dollar laptop. Sure you can fry a scope too if yer not careful, but at least a real scope is made for poking into the powered up guts of random gadgets.

But if all you want to do is look at computer waveforms then you don't need a scope. Even though scopes are even more funner than a bucket full of slide rules. :)
Also, one other thing;

In that case, are there any digital oscilloscopes that replicate that Analog Afterglow effect, that are relatively cheap?

Fox_GAMING_NTF
KVRist
225 posts since 11 Apr, 2019

Re: Looking for a good, cheap Analog Oscilloscope

Post Thu Nov 21, 2019 11:39 am

JCJR wrote:
Wed Nov 20, 2019 6:33 pm
For just looking at audio frequencies 20MHz is good enough. Even 10 or maybe even 5 MHz could be good enough for fairly non critical audio frequency waveforms and eye candy.

Dual channel would be nicer than single channel. They get old. A $50 50 year old eBay scope might not work very well. Some of the new $400+ Chinese lunchbox digital scopes look like a lots better deal if you can't find what you want used for less than $100. But the little $50 new postage stamp Chinese scopes probably a complete waste of money.

The "20 MHz" for instance might typically mean that a clean 20 MHz square wave (which has harmonics going way above hundreds of megahertz) would look like an attenuated sine wave on the 20 MHz scope.

That is why it can give a pretty decent picture of audio up to 20 kHz or even signals up to 100 kHz, but the closer you get to 20 MHz you get, the more rounded off and unrealistic the signal image.

That is no problem for casual audio use. Just trying to explain if maybe you needed to get a fairly accurate picture of a 5 MHz digital pulse train (Maybe for debugging low speed digital logic) then you probably want at least a 100 or 200 MHz scope to get a pretty accurate picture of the 5 MHz pulse shape. It probably wouldn't be very useful to see something resembling a sine wave on a 20 MHz scope. In other words, looking at a 5 MHz pulse train on a 20 MHz scope, you really wouldn't know if it was a good crisp pulse wave or a rounded almost-sine wave because both a crisp or smooth 5 MHz signal would look about the same rounded mess on a 20 MHz scope.

Which doesn't matter for audio eye candy. Am just trying to explain.

There is a real good free vst scope plugin that would be more educational and better eye candy for looking at computer audio waves than an old analog scope.

I mean scopes are great, a nerd's best friend. What cheezy sci-fi movie would be complete without a scope and bubbling test tubes?

But they are mostly good for poking a probe into dissected electronic guts. There are various scope adapters you can hook to a laptop, but if I am gonna poke a probe into some random electronic gear I want to use a scope because that is what they are made for.

I would be real sad to hook up a 100 dollar scope adapter to a 2000 dollar computer, poke a probe the wrong place in a guitar amp and fry the 2000 dollar laptop. Sure you can fry a scope too if yer not careful, but at least a real scope is made for poking into the powered up guts of random gadgets.

But if all you want to do is look at computer waveforms then you don't need a scope. Even though scopes are even more funner than a bucket full of slide rules. :)
Ok, so I'm probably going to get an old, analog oscilloscope, I've found an old Hitachi V-660 60MHz 2-Channel Oscilloscope, is this any good? It's hard to find any eBay Analog Oscilloscopes, or at least ones that actually show a trace. This one seems to have a nice, bright trace, too. But, I don't know.

JCJR
KVRAF
2897 posts since 17 Apr, 2005 from S.E. TN

Re: Looking for a good, cheap Analog Oscilloscope

Post Thu Nov 21, 2019 12:50 pm

Fox_GAMING_NTF wrote:
Thu Nov 21, 2019 3:28 am
Also, one other thing;
In that case, are there any digital oscilloscopes that replicate that Analog Afterglow effect, that are relatively cheap?
I don't understand what you describe. Could you find a youtube video or link a web still picture which shows what you mean?

CRT scopes worked similar to TV. An electron beam is scanned across left-right, up-down. Where the beam hits the screen phosphor it makes a glowing dot, often green on natural black background but not always.

If the beam is not being scanned it stays in one place and makes just a dot. When in motion it makes a line. The phosphor glows a little bit after the beam passes by, which combined with the eye persistence of vision makes you see a line rather than a moving dot.

There is a knob that turns up the voltage on the electron beam, making the dot brighter. If turned up real high sometimes it can "splash" and make a wider line as slow sweep speeds. Usually people would turn up the voltage for fast sweeps which might be too dim otherwise, because the beam doesn't hit the phosphor long enough to get it glowing good at a high scan rate.

If people use too slow sweep and negligently turn up the beam voltage too high it can make the phosphor persistence a little longer, with "fatter lines" but that is abusing the scope and if you do it very long or very often it will burn the phosphors inside the CRT face and ruin the CRT. Giving uneven traces and visible "burn marks" on the tube face when the scope is turned off.

There are also memory scopes that will sweep drawing a waveform, and then the picture of that sweep will persist for seconds or minutes afterward. Multiple sweeps in memory mode would draw many different waveforms on-top of each other. If they are maybe set to fade after say, 5 or 10 seconds, then the older images gradually fade away while new images keep getting added.

The oldest memory scopes did it with cunning tricks of biasing the scope tube. Fancy scope tube with extra grids that could make the phosphors keep glowing longer after the electron beam passes by. Back in the 1970's I had an old tektronix 200 MHz memory scope with that old-fashioned analog memory technology. It was a well built scope with a zillion features but every year or two another feature would fail. Luckily it had so many features it stayed useful until the mid 1980's after so many features had died that it was unusable. I didn't get it fixed because the dam scope was like $10,000 and replacement boards, replacement modules, there wasn't any part you couldn't buy to fix up the scope but every part for that scope was incredibly expensive. It would have costed more to keep that old scope going than to buy a brand new Hitachi or whatever.

Tech has got more advanced over the years but that Tek scope was full of amazing high-tech "unobtanium" parts built with the tech of 1960's-70's, to get a 200 MHz quality analog memory scope back then. Every part looked good enough to install in the space shuttle.

When digital got cheaper they quit making "analog memory CRT" memory scopes, and started making CRT scopes with digital memory instead. They still used CRT tubes, but managed the memory trick with digital memory driving the electron beam.

And then later still they replaced the CRT tubes with flat-panel displays, which is mostly what is made nowadays.

A 60 MHz Hitachi 2 channel scope would be fine so long as it works good. I wouldn't want to discourage you getting one because they can be so much fun. But if you just want a particular flavor of eye candy you could find a cheap flat panel TV with a USB stick port which can play video files, record some oscilloscope animation videos on a USB stick, and play them in a loop on the cheap flat panel TV. It would be a bigger more impressive "pseudo scientific" eye candy, if eye candy is the main purpose of getting a scope.

Fox_GAMING_NTF
KVRist
225 posts since 11 Apr, 2019

Re: Looking for a good, cheap Analog Oscilloscope

Post Thu Nov 21, 2019 2:07 pm

JCJR wrote:
Thu Nov 21, 2019 12:50 pm
Fox_GAMING_NTF wrote:
Thu Nov 21, 2019 3:28 am
Also, one other thing;
In that case, are there any digital oscilloscopes that replicate that Analog Afterglow effect, that are relatively cheap?
I don't understand what you describe. Could you find a youtube video or link a web still picture which shows what you mean?

CRT scopes worked similar to TV. An electron beam is scanned across left-right, up-down. Where the beam hits the screen phosphor it makes a glowing dot, often green on natural black background but not always.

If the beam is not being scanned it stays in one place and makes just a dot. When in motion it makes a line. The phosphor glows a little bit after the beam passes by, which combined with the eye persistence of vision makes you see a line rather than a moving dot.

There is a knob that turns up the voltage on the electron beam, making the dot brighter. If turned up real high sometimes it can "splash" and make a wider line as slow sweep speeds. Usually people would turn up the voltage for fast sweeps which might be too dim otherwise, because the beam doesn't hit the phosphor long enough to get it glowing good at a high scan rate.

If people use too slow sweep and negligently turn up the beam voltage too high it can make the phosphor persistence a little longer, with "fatter lines" but that is abusing the scope and if you do it very long or very often it will burn the phosphors inside the CRT face and ruin the CRT. Giving uneven traces and visible "burn marks" on the tube face when the scope is turned off.

There are also memory scopes that will sweep drawing a waveform, and then the picture of that sweep will persist for seconds or minutes afterward. Multiple sweeps in memory mode would draw many different waveforms on-top of each other. If they are maybe set to fade after say, 5 or 10 seconds, then the older images gradually fade away while new images keep getting added.

The oldest memory scopes did it with cunning tricks of biasing the scope tube. Fancy scope tube with extra grids that could make the phosphors keep glowing longer after the electron beam passes by. Back in the 1970's I had an old tektronix 200 MHz memory scope with that old-fashioned analog memory technology. It was a well built scope with a zillion features but every year or two another feature would fail. Luckily it had so many features it stayed useful until the mid 1980's after so many features had died that it was unusable. I didn't get it fixed because the dam scope was like $10,000 and replacement boards, replacement modules, there wasn't any part you couldn't buy to fix up the scope but every part for that scope was incredibly expensive. It would have costed more to keep that old scope going than to buy a brand new Hitachi or whatever.

Tech has got more advanced over the years but that Tek scope was full of amazing high-tech "unobtanium" parts built with the tech of 1960's-70's, to get a 200 MHz quality analog memory scope back then. Every part looked good enough to install in the space shuttle.

When digital got cheaper they quit making "analog memory CRT" memory scopes, and started making CRT scopes with digital memory instead. They still used CRT tubes, but managed the memory trick with digital memory driving the electron beam.

And then later still they replaced the CRT tubes with flat-panel displays, which is mostly what is made nowadays.

A 60 MHz Hitachi 2 channel scope would be fine so long as it works good. I wouldn't want to discourage you getting one because they can be so much fun. But if you just want a particular flavor of eye candy you could find a cheap flat panel TV with a USB stick port which can play video files, record some oscilloscope animation videos on a USB stick, and play them in a loop on the cheap flat panel TV. It would be a bigger more impressive "pseudo scientific" eye candy, if eye candy is the main purpose of getting a scope.
Ok, thanks!

Fox_GAMING_NTF
KVRist
225 posts since 11 Apr, 2019

Re: Looking for a good, cheap Analog Oscilloscope

Post Mon Nov 25, 2019 7:38 am

JCJR wrote:
Thu Nov 21, 2019 12:50 pm
Fox_GAMING_NTF wrote:
Thu Nov 21, 2019 3:28 am
Also, one other thing;
In that case, are there any digital oscilloscopes that replicate that Analog Afterglow effect, that are relatively cheap?
I don't understand what you describe. Could you find a youtube video or link a web still picture which shows what you mean?

CRT scopes worked similar to TV. An electron beam is scanned across left-right, up-down. Where the beam hits the screen phosphor it makes a glowing dot, often green on natural black background but not always.

If the beam is not being scanned it stays in one place and makes just a dot. When in motion it makes a line. The phosphor glows a little bit after the beam passes by, which combined with the eye persistence of vision makes you see a line rather than a moving dot.

There is a knob that turns up the voltage on the electron beam, making the dot brighter. If turned up real high sometimes it can "splash" and make a wider line as slow sweep speeds. Usually people would turn up the voltage for fast sweeps which might be too dim otherwise, because the beam doesn't hit the phosphor long enough to get it glowing good at a high scan rate.

If people use too slow sweep and negligently turn up the beam voltage too high it can make the phosphor persistence a little longer, with "fatter lines" but that is abusing the scope and if you do it very long or very often it will burn the phosphors inside the CRT face and ruin the CRT. Giving uneven traces and visible "burn marks" on the tube face when the scope is turned off.

There are also memory scopes that will sweep drawing a waveform, and then the picture of that sweep will persist for seconds or minutes afterward. Multiple sweeps in memory mode would draw many different waveforms on-top of each other. If they are maybe set to fade after say, 5 or 10 seconds, then the older images gradually fade away while new images keep getting added.

The oldest memory scopes did it with cunning tricks of biasing the scope tube. Fancy scope tube with extra grids that could make the phosphors keep glowing longer after the electron beam passes by. Back in the 1970's I had an old tektronix 200 MHz memory scope with that old-fashioned analog memory technology. It was a well built scope with a zillion features but every year or two another feature would fail. Luckily it had so many features it stayed useful until the mid 1980's after so many features had died that it was unusable. I didn't get it fixed because the dam scope was like $10,000 and replacement boards, replacement modules, there wasn't any part you couldn't buy to fix up the scope but every part for that scope was incredibly expensive. It would have costed more to keep that old scope going than to buy a brand new Hitachi or whatever.

Tech has got more advanced over the years but that Tek scope was full of amazing high-tech "unobtanium" parts built with the tech of 1960's-70's, to get a 200 MHz quality analog memory scope back then. Every part looked good enough to install in the space shuttle.

When digital got cheaper they quit making "analog memory CRT" memory scopes, and started making CRT scopes with digital memory instead. They still used CRT tubes, but managed the memory trick with digital memory driving the electron beam.

And then later still they replaced the CRT tubes with flat-panel displays, which is mostly what is made nowadays.

A 60 MHz Hitachi 2 channel scope would be fine so long as it works good. I wouldn't want to discourage you getting one because they can be so much fun. But if you just want a particular flavor of eye candy you could find a cheap flat panel TV with a USB stick port which can play video files, record some oscilloscope animation videos on a USB stick, and play them in a loop on the cheap flat panel TV. It would be a bigger more impressive "pseudo scientific" eye candy, if eye candy is the main purpose of getting a scope.
Just out of curiosity, do you know of any LCD /non-crt oscilloscopes that try to recreate that distinct CRT Afterglow?

And what I mean is, CRT Screens, they have a sort of glowy emission from them, where the LCD screens are sharp and flat, the CRT Screens can be sharp, but fade out, and seem more, I guess you could say, almost, "3-Dimensional", I don't know.

raintalk
KVRist
328 posts since 15 Mar, 2006

Re: Looking for a good, cheap Analog Oscilloscope

Post Mon Nov 25, 2019 11:12 am


JCJR
KVRAF
2897 posts since 17 Apr, 2005 from S.E. TN

Re: Looking for a good, cheap Analog Oscilloscope

Post Mon Nov 25, 2019 11:32 am

Maybe what you describe is phosphor persistence, or beam turned up too bright, or analog storage scope as described above.

Digital storage scopes often abbreviated DSO. I never had a DSO. Thought about buying one a few times but do not use one often enough nowadays to justify even a few hundred bucks.

But because I am not concerned at all about warm fuzzies of a lovely green glow, if I was gonna buy a new scope I would never buy an analog CRT scope. Been there done that. Even though they are lots of fun.

My last scope which still works great, which I bought after I only rarely needed a scope, and only for audio and other slow purposes, didn't need it for digital or radio, bought a 2 channel "what might be called portable" Chinese no-name 20 MHz scope off EBay Brand New about 20 years ago for about $100. I only use it a few times per year if that, and it still works as good as new with such light usage. It is relatively small for a CRT scope, only weighs maybe 15 or 20 pounds, about 15 inches wide and maybe 18 inches deep. The reason I got it new so cheap back then (when even no-name scopes were still relatively expensive) was that somehow in shipping a big container of rasberry soda syrup had been spilled all over the shipping box, completely soaking the box. But inside the cardboard and plastic wrapping the scope didn't get hit with any syrup and was fine except it had a strong rasberry soda smell for a couple of years. :)

I mean for occasional use it works fine. A nice little scope. Lots more portable and a slightly bigger CRT than my old $10,000 TEK 4 bay 7500 analog memory scope of yesteryear. I don't know if you would even like the traces of my little no-name Chinese scope because the traces are nice and thin and focused when the brightness is adjusted properly.

If I bought another scope it would be a little lunchbox DSO because the DSOs typically have much bigger screens than you hardly ever see on old CRT scopes. The things only weigh a few pounds. With trad benchtop scopes of yesteryear, even the "small ones" (except partially useless little handheld scopemeters) were really too big to carry to the work. Except in dire cases of need you had to carry the work to the scope.

The little lunchbox digital scopes are not much bigger than a digital multimeter and you can take the scope to the work about as easy as you can take a multimeter to the work. And they are so light you can move them where ever they are easiest to see and adjust. Wheras even with my "small" analog scope, 15 inches wide and maybe 18 inches deep and maybe 6 inches tall, there are only so many convenient places on a workbench to put the scope. So maybe if probing into a heavy power amp or whatever on the bench, might have to first look careful at the amp to get the probe set right, then look way over somewhere else where the big scope happens to be, to see what the signal looks like.

Now with a multimeter you can often prop the multimeter many places close to where you are working so you don't have to be looking back and forth so much doing actual practical work. With a little light big-screen lunchbox DSO all plastic exterior, it is about the same deal. A lunchbox DSO would prop up most of the places you could prop up a multimeter.

And the DSOs have SO MANY MORE FEATURES compared to old analog scopes.

It is kinda strange-- The $300 to $500 Chinese OWON or GWINSTEK or RIGOL look and operate very similar to multi-thousand dollar TEK lunchbox scopes. There are differences that would make a pro engineer want to buy the TEK (or tell his company to buy the TEK for him) same as long ago the engineer in the same situation would tell the purchasing dept to buy him a TEK CRT scope rather than a Hitachi CRT scope. But aside from precision issues and extra features worth it to a pro, it is amazing the bang for the buck the cheap little DSOs that look and operate near-identical "if you are a less-picky amateur without a purchasing dept to buy it for you." :)

IOW I don't give a damn about warm and fuzzy phosphor persistence. :) When adjusted properly, even my 20 year old no-name 20 MHz Chinese scope doesn't have warm and fuzzy phosphor persistence, just nice crisp tidy traces.

If you want warm fuzzy phosphor persistence, I bet somewhere there is a computer scope emulator plugin that does the animation on a computer screen better than a CRT can do it.

https://www.youtube.com/watch?v=NE9R4n0hMDc

https://www.youtube.com/watch?v=p_Bb-IWqnKM

JCJR
KVRAF
2897 posts since 17 Apr, 2005 from S.E. TN

Re: Looking for a good, cheap Analog Oscilloscope

Post Mon Nov 25, 2019 2:09 pm


puremusic
KVRist
46 posts since 24 May, 2017

Re: Looking for a good, cheap Analog Oscilloscope

Post Tue Nov 26, 2019 6:13 pm

Fox_GAMING_NTF wrote:
Wed Nov 20, 2019 5:30 pm
I'm looking on eBay, and I'm wondering;
for old Analog Oscilloscopes, is 20MHz ok? What is a decent amount for today? I'm just trying to find a decent analog oscilloscope that I can get, mainly because I am in love with the cool CRT-Afterglow effect, and, it could probably be actually useful for me, maybe, too. Please keep in mind that I'm only 14, and also know pretty much nothing about oscilloscopes (I've only just started looking into them maybe an hour, ~hour 30 mins ago?)

Thanks in advance!
Haha, you aren't alone I've been looking for one of these for awhile too! Sure to pick one up sooner or later.
Roland FP-90 - Touchkeys - TEC BC - MIDI Expression
Kontakt - Arturia Piano V - Sonivox Eighty-Eight - Spitfire Symphony Orchestra
whitepianos.blogspot.com

Fox_GAMING_NTF
KVRist
225 posts since 11 Apr, 2019

Re: Looking for a good, cheap Analog Oscilloscope

Post Wed Nov 27, 2019 8:56 am

Oof Noooo someone bought the one I wanted... And it was the last one, lol.

Fox_GAMING_NTF
KVRist
225 posts since 11 Apr, 2019

Re: Looking for a good, cheap Analog Oscilloscope

Post Wed Nov 27, 2019 9:11 am

JCJR wrote:
Thu Nov 21, 2019 12:50 pm
Fox_GAMING_NTF wrote:
Thu Nov 21, 2019 3:28 am
Also, one other thing;
In that case, are there any digital oscilloscopes that replicate that Analog Afterglow effect, that are relatively cheap?
I don't understand what you describe. Could you find a youtube video or link a web still picture which shows what you mean?

CRT scopes worked similar to TV. An electron beam is scanned across left-right, up-down. Where the beam hits the screen phosphor it makes a glowing dot, often green on natural black background but not always.

If the beam is not being scanned it stays in one place and makes just a dot. When in motion it makes a line. The phosphor glows a little bit after the beam passes by, which combined with the eye persistence of vision makes you see a line rather than a moving dot.

There is a knob that turns up the voltage on the electron beam, making the dot brighter. If turned up real high sometimes it can "splash" and make a wider line as slow sweep speeds. Usually people would turn up the voltage for fast sweeps which might be too dim otherwise, because the beam doesn't hit the phosphor long enough to get it glowing good at a high scan rate.

If people use too slow sweep and negligently turn up the beam voltage too high it can make the phosphor persistence a little longer, with "fatter lines" but that is abusing the scope and if you do it very long or very often it will burn the phosphors inside the CRT face and ruin the CRT. Giving uneven traces and visible "burn marks" on the tube face when the scope is turned off.

There are also memory scopes that will sweep drawing a waveform, and then the picture of that sweep will persist for seconds or minutes afterward. Multiple sweeps in memory mode would draw many different waveforms on-top of each other. If they are maybe set to fade after say, 5 or 10 seconds, then the older images gradually fade away while new images keep getting added.

The oldest memory scopes did it with cunning tricks of biasing the scope tube. Fancy scope tube with extra grids that could make the phosphors keep glowing longer after the electron beam passes by. Back in the 1970's I had an old tektronix 200 MHz memory scope with that old-fashioned analog memory technology. It was a well built scope with a zillion features but every year or two another feature would fail. Luckily it had so many features it stayed useful until the mid 1980's after so many features had died that it was unusable. I didn't get it fixed because the dam scope was like $10,000 and replacement boards, replacement modules, there wasn't any part you couldn't buy to fix up the scope but every part for that scope was incredibly expensive. It would have costed more to keep that old scope going than to buy a brand new Hitachi or whatever.

Tech has got more advanced over the years but that Tek scope was full of amazing high-tech "unobtanium" parts built with the tech of 1960's-70's, to get a 200 MHz quality analog memory scope back then. Every part looked good enough to install in the space shuttle.

When digital got cheaper they quit making "analog memory CRT" memory scopes, and started making CRT scopes with digital memory instead. They still used CRT tubes, but managed the memory trick with digital memory driving the electron beam.

And then later still they replaced the CRT tubes with flat-panel displays, which is mostly what is made nowadays.

A 60 MHz Hitachi 2 channel scope would be fine so long as it works good. I wouldn't want to discourage you getting one because they can be so much fun. But if you just want a particular flavor of eye candy you could find a cheap flat panel TV with a USB stick port which can play video files, record some oscilloscope animation videos on a USB stick, and play them in a loop on the cheap flat panel TV. It would be a bigger more impressive "pseudo scientific" eye candy, if eye candy is the main purpose of getting a scope.
Sadly, someone else bought that amazing Hitachi, but I've found this, I don't know if it's any good or not. At least to me it looks almost as if the traces are tilted, and I think I remember hearing that crooked traces are bad.
Here it is: Elenco 25 Mhz dual trace Oscilloscope model S-1325.

: //.

Fox_GAMING_NTF
KVRist
225 posts since 11 Apr, 2019

Re: Looking for a good, cheap Analog Oscilloscope

Post Wed Nov 27, 2019 9:36 am

JCJR wrote:
Mon Nov 25, 2019 2:09 pm
This vid is cute:
https://www.youtube.com/watch?v=xaELqAo4kkQ
EDIT: I've found an even better one, I think,:,

It's this:
B+K Precision Model 1477-P Oscilloscope 15MHz Dual Trace Boxed.
It looks really cool, it's only 15MHz, I don't know if there's a, "too-low", or bad MHz level, but I don't know. Now I just have to pray that no one will buy it, and that my parents will actually buy it (if they decide to : / in time before someone else does.)

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