Question - THD Measrement/Spectrum Analyzis

[LinuksGuru]

Hi !

I have a few questions regarding measurement of THD and their spectrum.

1) What PC software and sound card would you recommend? I am not in the mood to buy stand-alone spectrum analyzer for many thousands of $$$ just for hobby purposes.

2) I have constructed dummy load (to reduce output voltage from amplifier) using 10 Ohm 25W Russian-made wire potentiometer (rheostat) + speaker cables (D1.5mm 10sm no shield) + shielded audio cable (5 sm) with standard connectors.

The measured inductance of this pot is 20 uH (70+ rounds of thick wolfram alloy wire over ceramic tube).

I think parasitic inductance of this pot and short non-shielded cables should not induct considerable level of hum, since resistance of this circuit is very low (10 Ohm max).

Please correct me if I am wrong.

[Terry Demol]

Originally posted by LinuksGuru
Hi !

I have a few questions regarding measurement of THD and their spectrum.

1) What PC software and sound card would you recommend? I am not in the mood to buy stand-alone spectrum analyzer for many thousands of $$$ just for hobby purposes.

Best bang for buck =

Emu 1212M sound card, usually <$200

Rightmark audio analyser, free web down load.

cheers

T