I did my v2 revJ ... piece of cake swap 2 resistors is all.
Which version do you have though? is that a v3 or a newer one that's all SMC inside? If it's SMC, it'll be harder.
Here's some info
http://www.generalguitargadgets.com/bom/smallvlp.txtHere's a layout:
http://www.generalguitargadgets.com/pdf ... tj_lo2.pdfHere's my board with the changes marked

EHX Small Stone Issue J -- volume Drop mod
UNMATCHED VOLUME PROBLEM:
Many people have complained about a small volume loss when the Small
Stone is switched on. My Small Stone exhibits this behavior as well.
Here is a post from R.G. from Aron's Stompbox Forum on a possible
fix (modifications to the circuit) for this problem.
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From R.G. Keen
The loss of volume when engaged is correctable in the Issue J Small Stone
by changing the gain of the two-transistor preamp at the input of the circuit.
There are two 4.7K resistors at the emitters of the input transistors. One
(R7) goes to ground from the emitter of Q1, the second (R42) connects the
emitter of Q2 to the emitter of Q1. Those two resistors set the feedback gain
of the two-transistor compound.
Increase the 4.7K between the emitters (R42) to increase the gain. Start with
10K. Be aware that this will affect the stage biasing, so the headroom may
be affected; I don't think this will really be a problem.
The silly thing *ought* to have included a JFET buffer in front of it for
buffered bypass and a bit of gain in the first place.
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Dave Matelitz reported successfully fixing this problem by making these
part substitutions:
Changing R42 from a 4k7 resistor to a 10k resistor
Changing R11 from a 3k3 resistor to a 10k resistor
Tweak these two resistors until you get the volume right with no oscillation
in the signal.
http://www.generalguitargadgets.com/bom/smallvlp.txtEDIT:
Here's some info about the later versions, which might match yours better
http://web.archive.org/web/200712020834 ... /wp/?p=191And here's some info on some insane mods:
http://web.archive.org/web/200805240745 ... nstone.htm