[hpsdr] Pentalope audio

[a.groff]

(SW: PSDR TFD 10 Jan, Mercury V2.4, WInXP sp3; HW: Mercury, Pentalope, Ozy )

There seems to be a high noise level in the pentalope audio system. In 
L/USB, AM modes and no mic plugged in, the TX Mic meter reads in the 
range of -20 to -25db when PSDR MOX is keyed.  With MON on, the noise 
sounds like a mix of crackling white noise and unstable audio tones.  
Enabling the audio gate kills the noise as does enabling VAC.   The 
noise is present on the external TX RF output meter about 25-30 db below 
peak output and is visable on then TX Panadaptor.

The noise reminds me a bit of noises that in past time I traced to bad 
solder joints or over stressed/reversed polarized capacitors.

Does/has anyone else seen this characteristic ?    Is there some setup 
that I have missed ?

AL, K0VM