This
is a (no longer) new, reissue EH Small Stone that I
hacked into in a number of ways. Now, let's see if I
can remember. . .

There's
a 4PDT switch that switches all four filter caps in
one fell swoop (drilled into the "S" in the
word "small"). The down position is stock,
0.0068uF on all four stages. The up position is UniVibe
values (0.15u, 0.22u, 470p, 4n7, or something like that).
I tried some different values, and went with what sounded
good to me. If you want more info on this mod, you can
do a search on Google, Vivisimo, your favorite search
engine, or check out this web site: DIY Analog Guitar and Bass Music
Effects.
The
bright switch switches the input cap to the phase stages
(C3 in the issue J layout), between the stock 10uF and
a 0.1uf. It kind of takes the edge off of the Small
Stone's inherent "darkness."
I
installed a SPDT, center off, toggle switch on the outgoing
end of each of the four filter caps. The stock setting
is with all four switches in the up position, all four
stages configured as all pass filters. Switching any
of them to the down position diverts the filter cap
to ground, converting that stage to a low pass filter.
This is the PhaseFilter mod that Mark Hammer came up
with, except that I did it on all four stages instead
of just the last two. It's pretty cool when you have
all different cap values ('Vibe values) in each stage.
For more info, see http://hammer.ampage.org/.
The center position on each of these four toggle switches
simply breaks the connection at the outgiong end of
each filter cap. This effectively turns off the particular
filter stage. And, guess what? A single stage Small
stone actually sounds kind of cool. It's neat to be
able to isolate each filter stage when the caps are
switched to UniVibe values, too.
Then,
there's the mono/stereo switch. This actually does a
couple of things. Primarily, it's a vibrato switch,
breaking the part of the circuit that blends in the
clean, unmodualted signal, leaving only the modultaed
signal at the main output. The other thing that this
switch does is sent the clean, unmodulated signal to
the second output jack that I added, providing pseudo-stereo
outputs. See the photos, and check out the sound clips
that I recorded in stereo. (Man, that square hole in
the middle of the PCB is whacked, ain't it?)
Finally,
I replaced the goofy 1/8" power supply jack with
a standard 2.1mm barrel-type jack.



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