Although I had successfully measured amplifer distortion at the loundspeaker terminals, when I did this a second time I managed to damage my inbuilt PC sound card.
I was not using a voltage divider probe since I knew the AC levels were no more than 250mV. I don't fully understand what went wrong but there was probably a DC polarity discrepancy in my setup since the amplifier output is DC coupled and the centre voltage can be either + or - (actually only 5mV).
I looked to the REW HELP file on this but found nothing.
A post by AudiocRaver
http://www.hometheatershack.com/for...64-rew-connection-cabling-no-amp-speaker.html
seems to give the essence of the matter, that one must ensure the sound card and amplifier polarity match.
Is there an Idiot's Guide?
I was not using a voltage divider probe since I knew the AC levels were no more than 250mV. I don't fully understand what went wrong but there was probably a DC polarity discrepancy in my setup since the amplifier output is DC coupled and the centre voltage can be either + or - (actually only 5mV).
I looked to the REW HELP file on this but found nothing.
A post by AudiocRaver
http://www.hometheatershack.com/for...64-rew-connection-cabling-no-amp-speaker.html
seems to give the essence of the matter, that one must ensure the sound card and amplifier polarity match.
Is there an Idiot's Guide?