PC Based Oscilloscope

[bbirling]

Does anyone here use a pc based oscilloscope ? I have been looking at a product called Soundcard Oszillascope. Are there others that are better. I am cheap and looking for free or something I can build. Having used the DVMM for repair I would like to kick it up a notch when it comes to testing and building.



Bruce

[Fresh_Start]

Bruce - a search in the Amp Tools section will yield a lot of relevant info.

Chip

[RicharD]

IMO a basic traditional scope is much better.  You can find them for cheap.  Dual trace is a big plus.  For audio work there is no need for super speeds and other bells and whistles.

-Richard

[tubesornothing]

I have had a few.  The best so far is a pico scope, but they are expensive.

There are a number based upon sound cards, but dont have any isolation.  I betcha a google search will throw something up based on a sound card that has isolation.

[bbirling]

I asm finding tons of info, maybe to much. I would go with a basic scope but trying to keep the costs at a bare min. I wil check into the sound card ones with the isolation if I can find one.

Bruce

[kagliostro]

I think the same as Richard

but if you want to try a Virtual Instrument

http://www.virtins.com/page3.html

however a 5Mhz or a 10Mhz scope will work fine

PRR Docet

Kagliostro

[kagliostro]

For connections and protected connections

look at page 31 and 32 of the manual

http://www.virtins.com/MultiInstrumentManual.pdf

Kagliostro

[bbirling]

kagliostro

Thanks a ton. This is exactly what I was looking for. I have a laptop floating around here that I am going to use exclusivly for this.


Bruce

[PRR]

> Soundcard Oszillascope.

Soundcards are 10K impedance and accept 2V max (some a little more, some less) audio and !zero! DC.

Signals inside a tube guitar amp run 20V audio and 200V DC at 40K+ impedance.

Connecting a soundcard (even "protected") inside a tube guitar amp will load and mis-shape the signal you hoped to observe, and blow-up the soundcard. (Possibly the whole PC.)

> I have a laptop

The "sound card" is tightly integrated with the laptop main board. So the dire result is not just "no sound" but probably "dead laptop".

An *important* detail of a bench 'scope is the high input impedance (little loading) and wide-range attenuator (can take small or LARGE signals). You don't get that on a sound card. You may get that on the PC-connected external gizmo, but some I've seen only go to a few dozen Volts (ample for anything today *except* tube guitar amps), and anyhow that's $250.

A minor detail is that sound cards think "sound" goes to 20KHz, sometimes 50KHz, with VERY sharp cut-off. The lamest factory 'scope I ever used claimed 450KHz (honestly 200KHz). While you can learn a lot inside a 20KHz limit, in some odd cases it is VERY useful to have a clue what's happening just above the audio band.

IMHO, the most-crude and rude 'scope is much more suitable than a PC.

You could build a buffer for a sound card. Be a fair amount of work.

Heck, you can build a 'scope. DuMont did it. _I_ did it (in the gutted hulk of a DuMont 'scope). Not much more to it than a Champ.

[tubesornothing]

Notwithstanding PRRs comment, if you really want to do a scope on your PC (like to capture images) there are some small ones avalaible for $150 that have high input impedance and are isolated.  They plug in via USB.

Just google "USB oscilloscope"

Here is one I found.  No recommendation for it, I just found it. Max 300V with 10X probe.

http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/Test-Equipment/Oscilloscopes/USBscope50-1GS-s-Digital-storage-oscilloscope/77922/kw/usbscope50

[bbirling]

OK, so I conceded to spending a few bucks on a scope. The laptop I could use for some other venture.
Thanks for all the responses and insight.

Bruce