Shredmaster issues :(

[gutsofgold]

I have a shredmaster I built for a friend that just doesn't sound correct. At full volume and full drive it just above unity gain. I feel like this circuit should be offering tons of volume boost. It sounds nice and smooth very Marshall-esque distortion... just not loud at all. I used the following schematic and layout..

http://www.efektygitarowe.pl/marshall_shred_master/marshall_shreadmaster.gif
http://www.efektygitarowe.pl/marshall_shred_master/marshall_shred_master_layout.gif

See that 100k that sits right before the inverting input of the very last opamp stage? (right after a 220nF). Probing before this resistor I get a good level distorted signal, probing after it I get a very very quiet distorted signal. The last opamp stage then brings this up to about unity gain and because of this the volume control has to be maxed to even use the thing. Is this how the circuit operates? That 100k just pads the signal THAT much before hitting that last opamp stage?

[slacker]

Probing before this resistor I get a good level distorted signal, probing after it I get a very very quiet distorted signal.

That's correct, after the 100k resistor is the inverting input of the opamp, it's normal to have a very small signal there. The volume after that opamp should be about the same volume as before the 100k resistor, if not something is wrong round there somewhere.
I've got a real Shredmaster and it doesn't get much above unity, unity is about 2 -3 o'clock on the volume pot, so your build might be fine. If you think everything is fine with the circuit you could make the 100k resistor in the feedback loop of the last opamp bigger, that would increase the volume, you might need to make the 1n cap smaller as well to keep the tone the same.

[gutsofgold]

I replaced the 100k/1n opamp stage at the end with 220k/2n2 and it did nothing. I'm going to start scanning this layout for errors because two other users on here had issues with it.

[arma61]

^^
Hi shouldn't it be "doubling the resistance and halving the capacitance" ? looks like you doubled them both.