i used 100k pots in mine and it worked great. you just have to
experiment to find the right value capacitors for the effect you
want. my sounds go from down in crusty bass territory to pretty
chipmunk high. the actual sound of my 555s was from really high but
definitely audible up out of the audio range. you can find lots of
5v points on the chips in the lower left hand corner to power the
555s with.

things to keep in mind:

-if you use audio taper pots you can wire them backwards for even
response across the 555 range.

-cj's method of desoldering the clock pins, cutting the traces
underneath and resoldering sounds like the most efficient so far.

-drilling tiny holes in the clock pin traces to thread the 555
outputs up through worked very well for me to mechanically stabilize
the whole mess.

-make sure you reconnect traces you cut (except the clock pins).
these can be found by looking at which other points on the schematic
connect to the clock *outputs* (i think it's pins 4, 5 and 6 of the
same chip).

-soldering to the clock input pins can be a huge pain because of
their small size and close proximity.

good luck, and don't hesitate to ask questions.
greg

--- In tr-707@yahoogroups.com , "djdsl_tru" <dsl_tru@h...> wrote:
>
> Finally.. im getting around to working on this mod.
> Im in the process of building the 555 timers.
> It seems those of you using the 100k pots in the cicuit were
finding
> that they would go too high to be useful, I'm starting with 50k
pots,
> I suspect it will take some fine tuning to get them optimized.
>
> What's a good point on the board to power the 555's with
>
> It's great to see that you guys have done such great jobs with
your
> 707's. Hopefully i'll have some new info to share before im done.