[hpsdr] ghpsdr3 servers on Windows--DttSP setup question

[David McQuate]

Problem:  no audio, no spectrum or waterfall display!

The dspserver uses DttSP function Audio_Callback.
While the input buffer has reasonable (small) values, that depend on the 
signal level at Mercury's input,
the ouput buffer is always all zeros, so I think I'm missing some DttSP 
setup, but can't find it.
I've been looking at PowerSDR source code, but haven't found the DttSP 
initialization code yet.
  ****  Hints gratefully accepted ****

Before anything else, in dspserver the following calls are made into 
DttSP --

    Setup_SDR();
    Release_Update();
    SetTRX(0,0); // thread 0 is for receive
    SetTRX(1,1);  // thread 1 is for transmit
    SetRingBufferOffset(0,offset);
    SetThreadProcessingMode(0,2);
    SetThreadProcessingMode(1,2);
    SetSubRXSt(0,0,1);
    SetRXOutputGain(0, 0, 0.9);

and I see dspserver receiving commands from jmonitor which result in 
appropriate calls into DttSP
(there are also numerous getSpectrum commands)--

setFrequency 7048000
setMode 0
setFilter -2850  -150
SetRXOutputGain 30
startAudioStream 480

Selecting button / menu items on jmonitor results in dspserver receiving 
& processing additional commands,
such as--

setMode 1
setFilter 150 2850
setFilter 150 3950
SetRXOutputGain 90

--but the output buffer from Audio_Callback stubbornly remains all 
zeros.   :(

Dave / wa8ywq