Hi Tommy,
Most of your questions requires that I open and measure on a unit -
which I don't have.
My guess is still that you have a mess-up in the Attack/release timing
circuit. look at the meter output on your scope. select dc-reading. at
the longest release, "auto", it should take 3-4 seconds for a
dc-voltage, generated by incoming audio, to return to zero from ca. -5V
tommypiper wrote:
> Do you not understand my questions? I'm trying to be clear.
>
> 1) Is it normal for the waveform to move downwards and off the scope when
> applying make up gain? Is this some kind of DC offset?
>
Not clear what waveform you mean. Sc-vca? main vca? unit output? Try
understanding the circuit - the makeup is voltage added to the cv-input
of the main vca's.
> 2) With longer release settings the waveforms went flat. Is flat correct?
>
Yes. That should be clear from looking at the schematic. Release changes
integrator timing.
> 3) Should the CV be a flat signal on the scope? If so, then what is the
> waveform? Is the waveform leakage of AC through the rectifier?
>
Yes and no. it will mainly b ea dc-voltage, but as the sidechain filter
is not infinitely steep, there will be an ac component whick is larger
with fast timing (which, again, is easy to see if you read the schematic)
> 4) If the waveform is leaking AC, or audio, then why is there no waveform at
> the output of Pin 8 of the sidechain master VCA?
>
Try understanding how the vca's work. there's good info on Groupdiy, and
there's a lot of info on THAT's homepage. VCA theory is not all that
simple to explain.
> 5) Why is the waveform not present at the input of the TL074 on Pin 6, but
> it IS present on the first output of the TL074 on Pin 7????!!!
>
Please read about inverting opamp amplifiers - they are current-in, that
is there is a "virtual ground" at the -input.
> 6) Does this mean the TLO74 is causing the distortion? Or there is another
> source of this waveform than the natural output of the sidechain VCA?????
>
no and no
> 7) Why does the waveform go flat when I lengthen the release setting even at
> test point "C" upstream of the A/R circuit?????
>
it's a matter of understanding the circuit - there is no "reverse
isolation" here.
> 8) Is it normal to see the audio signal on Pin 7 of the TLO74?
>
Again - read the circuit. Audio L+R are summed and sent through the
sidechain vca - so yes, it will be present at the output of the VCA I/V
converter opamp.
> 9) Why does the distortion in the sine wave, visible at TL074 Pin 7, go away
> when I lengthen the release setting? How can the release effect the signal
> so far backwards in the circuit?
feedback through cv to sc vca, modulating audio.
> 10) It would be going backwards through the rectifier and several stages of
> the TL074, (which I thought would act as buffers)! Is it possible for the
> signal to travel backwards in the circuit like this?
Try understanding the feedback-sidechain-character of this compressor
Jakob E.
.... 
