Recommended Osciloscope

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Both of our shops are equipped with low/mid range Siglent scopes and signal generators. Like some of the other brands from years before the signal generator and scope mate up and can to automatic Bode plots and such.

SCOPE BUYING NOTES FROM AMP-HAUS:

Brand/Type/AGE
: If you are not designing new gear - just troubleshooting something or building a kit type thing you really dont need a powerful scope. Get a new scope, I know there are tons of used ones out there, but honestly; if you are just starting out get an affordable NEW one in a KNOWN brand that is readily available at REAL outlets in your country (not Amazon or eBay). The last thing you want is to have your "new" scope to become your new fix-it project. If you are at this stage in your electronics work journey, you do not want to start with troubleshooting and calibration of an antique scope. Plus the equipment to calibrate test equipment is even more costly.

"A DMM is better"?!: I forget who said this above but I will spare your name here... A scope can do everything a DMM can do in the right hands, and much more. A scope IS a DMM (MM), and so much more - it's also your audio probe. Yes those are handy little tools too, but If I had to pick ONE... Scope!

Channels: You need, at minimum, double the number of channels you are working on if you plan on testing/verifying in that way. But a single channel scope can troubleshoot things as well, it can just be tedious. You will need two channels to do a Bode plot with most scopes.

Kajillihertz: to get started with basic work you really do not need a scope that goes way beyond audio, honest. 10-50MHz is more than enough for day to day repair.

Don't forget to get a matching NEW signal generator; or highly serviceable old one if you want to do Bode Plots manually.

I am not saying you don't want a DMM or Audio Probe, those are handy. But a scope can do those things.

What else is in the shop?
Other than the really expensive test equipment, both of our repair rooms have exactly the same day to day test and repair equipment, so anyone can effectible work from either room. We both have a small Fluke Handheld DMM that we use for quick troubleshooting/verifications, most often for checking heavy guitar amps before we lug them into one of the repair shops. Both shops also have 2 tabletop 6 digit DMM's (HP), these get used much more than the handhelds, eventually you will likely want one of those. The downstairs shop also has the R&S UPD Audio Analyzer, and Tekronix 576 Curve Tracer.

BOTH SHOPS ALSO HAVE A COPY OF THIS OLD HANDY BOOK: "Handbook of Oscilloscopes: Theory and application" by John D. Lenk
While very old and dated (many scopes do the tests mentioned in the book automatically now). It does give you some enormously valuable insight as to how to use your scope and why it's doing what it does. (pics attached).


I hope someone finds my Sunday morning ramblings helpful.
Oh snap, do I see a fellow soldier? Combat Engineer?
 
Oh snap, do I see a fellow soldier? Combat Engineer?
7th Infantry Division (light) - Fort Old California, 13th Engineer Battalion (Sappers) - 1980's - I think we were the first ones through Fort Leonard Woods Sapper Leader School back in the day.

There are a bunch of veterans here. Great community, great people.
 
Do I really need one in the MHZ range if im only doing 20hz-20khz?
Yes. You need to be able to see things like parasitic oscillation, which in audio gear can be in the hundreds of kHz or even MHz range.

This is where digital scopes make things awkward. If you have the timebase (and therefore sample rate) set to look at audio signals you probably won't see any HF stuff without changing the setting. On an analogue scope it will show up as a blur, even on a slow timebase.
 
Thx...I have an old tube textronix 561...x & y modules. It still works ,!!@!. I use it for audio signals and dc heater stuff...I have the matching 25x probe but have never used it. With this 25x probe can I look for hash on 300vdc ?. I don't want to fry my old scope because it to shows me audio Square wave anomolies.
I am waiting for the laughter that I am sure to get....
Thx for all your help on my questions...thx Ian
 
Im really happy using REW for its digital scope and FFT functions for audio ,
Im glad I picked up a Tek 2215 also , It probably needs a few caps changed but it still gives a very good account of itself .
I had a few ancient tube scopes along the way , they all went down in a puff of acrid smoke in the end 😢
 
Pretty much any Tektronix scope would be a good choice. If you need data transfer there are USB adapters available on ebay to replace the floppy drive in the earlier digital Tek scopes. I have a 3000 series and it's been excellent. I do audio servicing as a business and I often use more than 2 channels, but that's mostly to save time. I also use analogue scopes and they are perfectly good enough 95% of the time. JohnR is correct, I would recommend 20MHz minimum for analogue. Probably 100MHz digital.
 
Im really happy using REW for its digital scope and FFT functions for audio ,
Im glad I picked up a Tek 2215 also , It probably needs a few caps changed but it still gives a very good account of itself .
I had a few ancient tube scopes along the way , they all went down in a puff of acrid smoke in the end 😢
Do you use a probe with REW? How d oyou have it setup?
 
I didn't know what REW is? I looked it up.
I use an HP 2380 Spectrum analyser, Smaart live on the computer and an Audio Precision analyser for my audio and acoustic measurements.
 
Yeah its possible to use a scope probe into a hi-z input on a soundcard if you want ,
the bandwidth you get depends on the interface and sample freq .

Im a massive fan of Room EQ Wizard , I felt instantly at home the moment I tried it ,
now ok its not quite the same as an AP rig ,but bang per buck its hard to beat .

I use a Feeltech arb gen , cheap and cheerfull ,but with 14 bit perfomance its good enough for most tasks .

I have a Fluke 187 ,which gives me precise readings in db , that allows me calibrate levels from the Arb and within REW to a high degree of accuracy .

Ive a few old but good bits of Bruel & Kjaer for precise acoustic measurements , but to be honest its my ears I use as the final arbiter of what sounds good or not .
 
This is where digital scopes make things awkward. If you have the timebase (and therefore sample rate) set to look at audio signals you probably won't see any HF stuff without changing the setting. On an analogue scope it will show up as a blur, even on a slow timebase
I was wondering if I should trade a Tektronix 465M (that my AF vet brother gave me) for a newfangled, lower cost digital scope. It's a keeper now, and I'll pick up something digital as well. Thank you!
 
Those were good scopes back in the day. Pretty old now, and the floppy drive for storing means you probably won't be able to share screen captures or raw data with anyone (I'm just assuming you don't still have a computer with a floppy drive and a stash of disks).

That's not necessarily a show-stopper. A colleague here has a similar Tektronix scope and he's about to replace the floppy drive with USB.

I'll let you know how it goes (I might need reminding)
 
"A DMM is better"?!: I forget who said this above but I will spare your name here... A scope can do everything a DMM can do in the right hands, and much more. A scope IS a DMM (MM), and so much more - it's also your audio probe. Yes those are handy little tools too, but If I had to pick ONE... Scope!

Two different instruments. For voltage measurements, a DMM has a lot better accuracy than a scope.
 
Yeah its possible to use a scope probe into a hi-z input on a soundcard if you want ,
the bandwidth you get depends on the interface and sample freq .

Im a massive fan of Room EQ Wizard , I felt instantly at home the moment I tried it ,
now ok its not quite the same as an AP rig ,but bang per buck its hard to beat .

I use a Feeltech arb gen , cheap and cheerfull ,but with 14 bit perfomance its good enough for most tasks .

I have a Fluke 187 ,which gives me precise readings in db , that allows me calibrate levels from the Arb and within REW to a high degree of accuracy .

Ive a few old but good bits of Bruel & Kjaer for precise acoustic measurements , but to be honest its my ears I use as the final arbiter of what sounds good or not .
Which scope probe do you use in your hi-z input 1/4" trs in your soundcard?

Wouldn't you be able to use your computer as a waveform generator also?
 
Which scope probe do you use in your hi-z input 1/4" trs in your soundcard?

Wouldn't you be able to use your computer as a waveform generator also?

I actually ended up using exactly that sort of setup for testing a microphone, this weekend. For that purpose, i got a couple of old but sealed Pomona BNC to 1/4" plug adapter a few years back (not cheap, mind you). Didn't really care about absolute values (although "calibration" wouldn't have been a big deal), but worked a treat with a fixed 10x Tektronix probe. All through a Focusrite Saffire 6 USB2, using REW (also for the signal generator).
 
A colleague here has a similar Tektronix scope and he's about to replace the floppy drive with USB.

Please do report back. I have some old boat anchor scopes I haven't powered on in a while, but if I had a way to get data off them more easily it would be more tempting.
I still have a GPIB interface somewhere in my list of things to check to see if plotting to an emulated GPIB printer is an effective way to get captures off an old scope, but being able to hit the save to floppy button and actually save to a USB stick instead would definitely be a lot more convenient.
 
I actually ended up using exactly that sort of setup for testing a microphone, this weekend. For that purpose, i got a couple of old but sealed Pomona BNC to 1/4" plug adapter a few years back (not cheap, mind you). Didn't really care about absolute values (although "calibration" wouldn't have been a big deal), but worked a treat with a fixed 10x Tektronix probe. All through a Focusrite Saffire 6 USB2, using REW (also for the signal generator).
Interesting, using the "Scope" part of REW? Did you hook it up to the Hi-Z input or the regular Analog input of your interface?
 
Interesting, using the "Scope" part of REW? Did you hook it up to the Hi-Z input or the regular Analog input of your interface?

Indeed, the Scope tool, and yes, of course, using the Hi-Z input (which is as close to a 1meg oscilloscope input as you'll get, on a consumer audio interface).
 
If you use a TEK Scope, usually one of the channels has a 1 volt output on the rear panel. Full BW and input Z and High Voltage through the probe. Many time I have used this and feed into my AP, however 75-80dB is best you can get (No Auto Range).

Duke
 

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