And now I've modified the circuit by swapping R98 from the 4.7K default value up to a 10K value. Now, when the MG Delay is turned to zero, it correctly applies the MG all the time...there's no more weird transient at the start of each new note.
Audio demos of before and after this mod are available at:
http://synthhacker.blogspot.com/2013/08/polysix-modifying-mg-delay-circuit.htmlChip
--- In PolySix@yahoogroups.com, "chipaudette" <chipaudette@...> wrote:
>
> Sorry about the weird link...it seems that the URL is one character too long for the line-wrapping here. Wacky.
>
> Anyway, I've spent a little time exploring the MG circuit and how the MG Delay interacts with it. It appears that, on my Polysix at least, the MG Delay Control Voltage (CV) coming out of the DAC is slightly too high, which thereby allows the keypress to suppress the MG signal, even when the MG Delay is zero. Bummer.
>
> If you're interested, you can check out details of my measurements at:
>
> http://synthhacker.blogspot.com/2013/08/polysix-exploring-mg-delay-circuit.html
>
> To fix this problem, I can't really address the output of the DAC (beyhond recalibration, which I've done). So, as mentioned in the post, I'm going to alter the circuit to affect the voltage that is compared to the MG Delay CV. If I can raise up that voltage slightly, I'll achieve my goal of avoiding MG suppression when the MG Delay is zero.
>
> Chip
>