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PC Based Oscilloscope or standard?

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PC Based Oscilloscope or standard?

Postby pointillist on Mon Jan 22, 2018 12:14 pm

Hey all- Searched the archives, but most of the oscilloscope posts are pretty old. Looking to get one mostly to do tape machine (Tascam TSR-8, don't laugh) calibration, but I'm sure I'll use it for other things as well. Been looking at some of the newer PC based oscilloscope hardware/software packages as well as the old physical standards. Anyone have any recommendations or experiences? The SainSmart stuff looks interesting, but I also see some decent Tektronics for sale around me on craigslist.

Any recommendations?
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Re: PC Based Oscilloscope or standard?

Postby uglysound on Tue Jan 23, 2018 8:27 am

Are you going to use it after you calibrate the tape machine?

To me, the older hardware oscilloscopes are still the best value. A dual-trace 100 Mhz Techtronix can be found for well under $300 if you watch for deals.
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Re: PC Based Oscilloscope or standard?

Postby Justin Foley on Tue Jan 23, 2018 11:12 am

The Tek-type scopes are cool if you can find a reliable one that works. I've got a Leader scope in my rack that's probably not at all calibrated but fine for tape machine alignment.

Still, there's this whole new world of cheap, handheld O-scopes. Like this DSO Nano v2. I haven't gotten one yet but boy are they tempting. Less than $100 and if it works, it's probably in-spec, can store signals and has a built-in function generator.

Hmmmm.

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Re: PC Based Oscilloscope or standard?

Postby twelvepoint on Tue Jan 23, 2018 11:34 am

Related question: I have an older dual trace Tek scope (I think it's 85mHz, or similar) and it's always worked fine for my crude use such as tracing and comparing audio test signals.

Should I care about calibration? Seems like if I adjust the width and amplitude as one would commonly do, then essentially the thing is in a constant state of calibration, you know? Generally anything that needs an absolute, calibrated reference, I'd reach for a multimeter, tone generator, MRL tape, measuring cup, or cubit stick.
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Re: PC Based Oscilloscope or standard?

Postby TylerSavage on Tue Jan 23, 2018 11:57 am

Ever since being shocked through my laptop, by a guitar amp, fed by a signal generator with a USB interface, I've really enjoyed using hardware only bench equipment
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Re: PC Based Oscilloscope or standard?

Postby pointillist on Tue Jan 23, 2018 3:11 pm

In reading reviews of the PC based systems, I've been surprised at the amount of reviews involving electrical shocks. Maybe new users? Or wonky systems?

Am totally planning on using it after calibration is over, thanks for the advice on these- we have a pretty cool surplus facility who typically has good quality use scopes, think I might head out there over the weekend and take a look. Although that DSO Nano is pretty interesting looking.. I'm making a list of scope requirements listed in my Tascam shop manual today to make sure I know what features I need. Thanks for the advice, folks.
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Re: PC Based Oscilloscope or standard?

Postby Anthony Flack on Tue Jan 23, 2018 4:59 pm

twelvepoint wrote:Related question: I have an older dual trace Tek scope (I think it's 85mHz, or similar) and it's always worked fine for my crude use such as tracing and comparing audio test signals.

Should I care about calibration? Seems like if I adjust the width and amplitude as one would commonly do, then essentially the thing is in a constant state of calibration, you know?


I love my old CRT scope. Like you, I've found it perfectly adequate for my crude use (audio and a little bit of logic at 1980s clock speeds). And the vector display is so pretty. I've also heard it said (was it on here? probably) that you're better off with an old analogue scope than a cheap digital one if you intend to work on high-powered things like amps.

It seems to be calibrated more-or-less right but I use it more for getting a rough eyeball of what's going on than making super-precise measurements anyway. You could check it if you have a function generator and multimeter though.

The width and amplitude should be on clicky (not continuous) knobs and the knobs should be pointing to numbers that indicate (correctly, with luck) the time and voltage change represented per grid division on the screen.
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Re: PC Based Oscilloscope or standard?

Postby Justin Foley on Thu Jan 25, 2018 1:10 pm

The importance of calibration depends on how you use it.

For regular alignment of a tape machine (at least a Studer 810 and an MCI JH-110), I've never needed to worry about scope calibration. I'm looking at things like relative signal reproduction, so it's just important that the channels report things in a reasonably similar way. Given the ability to adjust channels, that's not hard to do.

The absolute references are provided by the MRL tape and setting incoming test tone levels at 1.227V RMS. I've always tested this latter measurement by checking the internal audio cards with a multimeter. I guess it'd be cool to do that with a calibrated scope if you knew how, but it's not at all a requirement.

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