two questions about DirtBag delay

[Dimitree]

hi everyone, 

I have some question regarding two parts in the DirtBag delay:
1) why R17 is not tied to ground like on the deluxe memory man? what's the difference?
2) R11/R12 should be lowered from 68K to 47K when using V3205. Is this needed because the circuit is powered with 9V instead of 15V (and so inherent to the compander supply), or only for the headroom of V3205? more specifically, when using another BBD (not V3205) but still using 9V supply, should that resistors be lowered too?

thank you!!

[m-Kresol]

could you post a link to the schematic? I couldn't find it in the archives...
anyhow, just from the top of my head I think to remember that the v3205 are run on lower voltages than the MN3005. that could be the reason for the different R11/12 values, but I'm basically just guessing.

[Scruffie]

1) Converted from -15V to +15V
2) The Compander needs biasing to half supply at its output, this changes with supply, those resistors set the bias.

[Dimitree]

could you post a link to the schematic? I couldn't find it in the archives...
anyhow, just from the top of my head I think to remember that the v3205 are run on lower voltages than the MN3005. that could be the reason for the different R11/12 values, but I'm basically just guessing.

of course, here it is:
http://www.madbeanpedals.com/projects/Dirtbag/DirtBagDeluxe.pdf

1) Converted from -15V to +15V

that was my guess, but I can't explain why..I mean, out of curiosity, why many other parts in the circuit are tied to ground just like on the original DMM(-15V), while ONLY this part is "inverted" (without considering opamp supply pins and cap polarity, of course)?
for example, the close parts C11 and R14, and many other, they just are tied to ground like on the original..
Why R17 need to be to V+?
if you tied it to ground, what's the difference?

2) The Compander needs biasing to half supply at its output, this changes with supply, those resistors set the bias.

ok so if I understand correctly it is not because of the BBDs used after the compader..
I need to check carefully the datasheet to understand how to calculate those resistors in different situations..

[Dimitree]

up please