Using sound card to measure amps/preamps

doors666

Well-Known Member
Joined
Sep 15, 2008
Messages
1,776
Points
113
Location
bangalore
anyone has done this? measure thd+n, phase etc. i will probably need some attenuator for use with amps. is isolation needed? what about impedances, this would act like a scope probe right? whats the best free software for this.
i guess odac wont do as it has no mic input. how good is the asus essence mic input.
 
I have used a few .... including Virtins software.

There is lots of free ware available for signal generators, O'scopes and Spectrum analysers.

Yes, Ground isolation etc can be a Big issue. ... Must be careful. A laptop operating on battery is a good idea.

My experience is that Sound cards roll off VERY Sharply after 20 KHz. You will not be able to generate or view a 10KHz sq wave ( Critical for audio testing) via a sound card.

The sound card based soft instrumentation is a good thrill initially, but cant substitute a serious o'scope. Software is also great as a spectrum analyser, but the bandwidth restraints are very obvious.

Recently I discovered that Good Condition used Osciloscopes are available on OLX.in at Throw away prices ( Rs 4,500 upwards). A function generator for Rs 2,000 With Digital readout !

This is in the price range of a descent sound card !

If you want to go the whole Hog, a Brand new Tek Scope with FFT :


TEKTRONIX - TBS1042 - OSCILLOSCOPE, 2CH, 40MHZ, 500MSPS

scope for just Rs 23,413

TBS1042 - TEKTRONIX - OSCILLOSCOPE, 2CH, 40MHZ, 500MSPS | element14 India
 
I have used a few .... including Virtins software.

There is lots of free ware available for signal generators, O'scopes and Spectrum analysers.

Yes, Ground isolation etc can be a Big issue. ... Must be careful. A laptop operating on battery is a good idea.

My experience is that Sound cards roll off VERY Sharply after 20 KHz. You will not be able to generate or view a 10KHz sq wave ( Critical for audio testing) via a sound card.

The sound card based soft instrumentation is a good thrill initially, but cant substitute a serious o'scope. Software is also great as a spectrum analyser, but the bandwidth restraints are very obvious.

Recently I discovered that Good Condition used Osciloscopes are available on OLX.in at Throw away prices ( Rs 4,500 upwards). A function generator for Rs 2,000 With Digital readout !

This is in the price range of a descent sound card !

If you want to go the whole Hog, a Brand new Tek Scope with FFT :


TEKTRONIX - TBS1042 - OSCILLOSCOPE, 2CH, 40MHZ, 500MSPS

scope for just Rs 23,413

TBS1042 - TEKTRONIX - OSCILLOSCOPE, 2CH, 40MHZ, 500MSPS | element14 India

I already have a much better scope, tek tds2024 4ch, 200mhz, 2gsps, 3 probes and a current probe. I also have a siggen but it only does pwm and sq wave. i was able to use odac (using audacity) to generate upto 20khz sinewave perfectly and i can see output on the scope. I use this to detect oscillations etc.
I cant do distortion analysis with this setup. it also doesnt have a usb interface, so i cant get the waveforms on to a pc. I am ok with just 1khz to get some idea of thd levels.
 
For a measurement setup, you should use line-out->amp->jig->line-in.
The jig is needed to protect the line-in from high voltages of the amp. Look at Figure 1.6 for the jig in Arta user manual.

Regards,
Goldy
 
Follow HiFiMART on Instagram for offers, deals and FREE giveaways!
Back
Top