[LAU] turning a consumer soundcard into "prosumer" w/ quasi-balanced outs

[Niels Mayer]

Fons:

Thanks for your suggestions and input. Here is are some more outputs
from a different dynex dx-sc51 soundcard:

http://nielsmayer.com/npm/jaaa-db50xg-L-fullband-captureoff.png
http://nielsmayer.com/npm/jaaa-db50xg-L-fullband-captureon.png
http://nielsmayer.com/npm/jaaa-db50xg-L-lowfreq-captureoff.png
http://nielsmayer.com/npm/jaaa-db50xg-L-lowfreq-captureon.png
http://nielsmayer.com/npm/jaaa-db50xg-R-fullband-captureoff.png (note
interesting anomaly at ~14K)
http://nielsmayer.com/npm/jaaa-db50xg-R-fullband-captureon.png
(anomaly disappears in the noise)
http://nielsmayer.com/npm/jaaa-db60xg-R-lowfreq-captureoff.png
http://nielsmayer.com/npm/jaaa-db50xg-R-lowfreq-captureon.png

Capture on vs capture off on the soundcard shows a big difference in
the noise floor.
Is the -62db/hz&-66db/hz at 0.1hz an anomaly?

In 'jaaa' the 0.1 hz value "jumps around" as if there were a shifting
DC level. It can be seen in 'yass' for example... "capture off" shows
a flat line with AGC turned on. "capture on" shows a noise that is
entirely positive voltage, which can be raised higher by adjusting the
capture gain above 0db.

Thus the purchase of a used $20.00 soundcard to replace this $0.99
one. You gets whatcha pay for...

Niels
http://nielsmayer.com