PC-based scopes, anyone found a good one for <1000v and audio?

[Alex R]

I need to upgrade and so far as possible go for compact test gear. I wondered if anyone has found a computer-based digital scope that can look at 500-1000v signals with a 10x probe or something? Low bandwidth is fine of course but I think a high sampling rate might be necessary with audio signals. Obviously HT is the main worry...? Any recommendations/warnings to offer?

Any other suggestions for making a guitar amp repair man's test equipment lighter, smaller and more portable would be welcome too. I have in the past happily relied on pretty ancient boatanchor style kit, and even gloried in it, with few problems, but I need a bench i can move around every so often due to a complex series of house moves.

[nevetslab]

While I haven't yet used it for tube gear, I did pick up a Velleman PCSGU250, mostly to get a Marine Biologist firm that I'm doing hydrophone preamp work for all on the same page for working with testing hydrophone arrays using piezo film transducers in close-coupled acoustic drive to couple to their hydrophones. The Velleman, with their downloaded latest software, allows for very decent Bode Plot work out to 1MHz. I use an Amber 3501a Audio Analzyer as the front end for it, so I have a good conditioning amp in the closed-loop measurement system.

For Tube work, I've been meaning to couple the inputs of their PC scope with the Tek P6009 X100 scope probes I have in my inventory, as well as their P6062 or P6063 X1-X10 probes. It's not a perfect system, but it does offer a lot of bang for the buck. I think I picked it up on line, delivered for aroudn $160. It took me some time getting used to it, having been spoiled by large Tektronix, LeCroy & Analogic scopes, both analog storage and digital storage. None of which, though, are portable!

The Velleman system has allowed replication of test results to be shared and varied at a distance, and for the Marine Biologists who are always out on research vessels tracking different species of whales and dolphins, it's allowed field checkout without having the complexities of full in-water calibration.

[TimmyP1955]

I gave up looking and got an Owon SDS6062 off eBay for $300. Not a great scope, but it gets the job done. Has a 7" (I think) color screen, Voltage and Frequency readouts, FFT (not has fast to use as what's on my phone, but it works), VGA out to use with that old monitor you have lying around. Didn't know till I got it that it has a rechargeable battery inside.

[Alex R]

The Owon SDS6062 looks neat, but is it as robust with, say, ripple on SVT plate voltages, as the old analogue scopes I've always used so far?

[Alex R]

I think I'd be happier with a stand-alone scope on consideration, don't want to be faffing with the mouse etc. I am a bit unsure how to read specs though Look at this for instance:

Buy Digital Oscilloscopes Tektronix TDS2001C Digital Oscilloscope, Digital Storage, 2 Ch, 50MHz, Colour Tektronix TDS2001C online from RS for next day delivery.

specs here: http://docs-europe.electrocomponents...6b80f10698.pdf

Maximum input voltage 300vRMS. Does that mean at the probe tip, or after probe attenuation? Sorry to be dim...

[pdf64]

It must be 300V at the scope inputs, as they sell a 20kV probe as an accessory (only £1500!).
The regular non-attenuating probes are also 300V rated.
Pete

[Alex R]

It must be 300V at the scope inputs, as they sell a 20kV probe as an accessory (only £1500!).
The regular non-attenuating probes are also 300V rated.
Pete

Lordy! And well deducted! So with a 10x probe it would handle anything an SVT might throw at it. Definitely time I started updating and downsizing - I need to set up again in a much smaller space.

[pdf64]

If you're moving more than once, and your eventual workspace will be reasonably sized, perhaps consider renting some temporary workspace and keep your existing gear?
With the cost of new equipment, it may work out financially.
Pete

[Alex R]

that's sensible, but I am itching to spend a bit of cash and kind of tired of operating on a shoestring with old crap off ebay that I bought whilst paying for the luxury of divorce lol. Anyone need four nonfunctioning analogue scopes and one that works now and then? No? Sixteen unrepairable amps? Twenty Marshall power boards with leaky bias circuits? ...and many other pointless wonders. Like an isolation transformer it takes two men to lift? And an industrial variac that would have kept Dorothy's house on the ground... actually I am keeping those two .

I may well rent a little space, yes. But there is so much moving from town to town in the offing that I need to travel light. Also all my kit is in cardboard boxes in storage and there were a shamefully large number of them, yet when I sit and think about it I actually need about one in ten of those boxes, you know how it is...

[Tom Phillips]

Alex R,
You will find some interesting information about using scopes to observe high voltage signals in the discussion at http://music-electronics-forum.com/t31492/
Regards,
Tom

[Mick Bailey]

So with a 10x probe it would handle anything an SVT might throw at it.

Maybe with a fixed 10x probe. But avoid one that's switchable between 1x and 10x.

It doesn't say in the specs, but some scopes are only rated for maximum voltage with the vertical sensitivity on the highest setting. Also look at the de-rating for high frequencies.

[Alex R]

Alex R,
You will find some interesting information about using scopes to observe high voltage signals in the discussion at http://music-electronics-forum.com/t31492/
Regards,
Tom

Thank you - that is an excellent thread and answered all my questions. Especially the last post .

[nevetslab]

If you look around, you'll find nearly all X10 Scope Probe are only rated at 300VDC at the probe tip. There's some X100 probes, inexpensive ones that also are only rated for 300V. The true X100 scope probes that carry a 1kV to 1.5kV rating aren't inexpensive. If you look around, you might be able to pick up some used working Tektronix P6009 X100 probes. It's a 60's-70's vintage probe, but they work well. 120MHz BW. They also made a 25MHz X100 probe of that vintage, think it's a P6008. I don't have my Tek catalogs here to verify that. The 5mV thru 5V/Div range becomes 500mV thru 500V/Div with them.

[J M Fahey]

FWIW I posted a 1000V capable attenuator for PC scopes a couple years ago.

To be more precise, it was meant to see plate waveforms on a *software* PC scope in overdriven tube guitar amps, go figure