Shin-ei Octave - more volume?

[RickL]

I successfully built the Shin-ei Octave from Topopiccione http://topopiccione.atspace.com/PJ15ShinEiOctave.html

Schematic http://topopiccione.atspace.com/pjimages/ShinEiOctave.sch.jpg

When engaged it sounds a little lower in volume than when bypassed. I'm guessing because the original was not true bypass it was designed to match the volume of the loaded down non- true bypass, similar to the Small Stone.

I've managed to get a bit more volume by shorting the emitter of Q11 directly to ground (replace R41 with a jumper) but it's not quite enough. Ideally I'd like to add a master volume control that would give from just below unity to a bit of a boost (2 x ?). Is there a resistor I can replace with a pot to acheive this?

I could just tack on a little booster but I'd like a more elegant solution.

[chaddhamilton]

I dunno Rick.  The Shin-ei Fuzz suffers from the same volume drop problem.  My approach to "fix" the issue was to jumper the wiper lug of the Fuzz pot to the Wiper lug of the Volume pot, and a difference does it make.  Dunno if this approach will work for this pedal though.

Chadd

[J. Luja]

for more boost, just change r40 to a 4.7k or so. instead of a master volume, it's probably easier to just change sw1 to a clean volume control, take a 100k pot, connect its outer lugs to the input and gound and connect the wiper to the end of r36 that normally connects to the input (on that layout you'll have to cut the trace and then jumper the connections for sw1)

[RickL]

That did the trick. I added a 5k pot, wired as a variable resistor, in series with R40. It gave me almost exactly the extra boost I was looking for. A 10k would probably work as well for a little more boost but I'm happy with it the way it is.

Thanks so much.

Rick