If you are talking about audio background noise, (which is partly from the
microprocessor), I believe some found checking grounding of the boards and
other grounded cables helps.
Also, if you use too low an impedance headphones, you will hear a strong
background. This is especially noticeable with wide response hi fi phones.
Use higher impedance communications head phones like the old magnetic
phones, (Trimm, etc.) or military high impedance phones like the 15,000 ohms
types and you do not have to advance audio gain as much, and the background
noise is reduced.
-Stuart
K5KVH
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