[Elecraft] OT - sound cards

[Erik Basilier]

Joe, thanks for those comments. You seem to have spent a lot of time looking
into these issues. Jim Brown said something about your business. Would I go
too far OT if I asked in what business context you look at sound cards?

 

73,

Erik K7TV

 

Joe Subich wrote:

 

Correct ... that $30 USB headset is a $0.05 electret capsule and a $2.00 USB
audio chip (C-Media or TI/Burr Brown).  The best thing in the world is to do
the A/D from a higher level signal (23-26 dB more drive) and power the
device from the relatively "clean" USB power away from the multiple amp
digital supplies with their 600 to 800 MHz noise.

 

I used to argue that the internal sound card was fine and in the early days
with microHAM we actually tested many sound cards and motherboards which had
good dynamic range (low noise floors).  But recently - mainboards are being
designed with very little regard to decoupling and routing of audio signals.
The on board sound systems are being placed for ease of connecting to the
system bus or PCI bridge controllers which often means long audio runs in a
very noisy environment.  When that is coupled with a dynamic mic, and 20 dB
of gain boost in the mic circuit of the sound chip it is easy to see why the
mic inputs are so dirty (and the soundcard dynamic range drops to less than
60 dB! from about 96 dB for a good

16 bit A/D).

 

73,

 

    ... Joe, W4TV