If your going the hex-schmitt trigger route, i recommend using a 5v
voltage regulator & at least a 100uf polarized cap between the IC
power supply pin and ground. Considering though how small "high
capacity" caps are these days, maybe I'd even consider a 1000uf to be
safe. The 5v regulator (those 3 pin large transistor lookin' things)
is necessary because the freq. of schmitt trigger oscillators is
highly dependent on power supply.

If you go that route, tell me the IC you'll use + the power supply and
what frequency range you want it to cover, and i can give you the
resistor + capacitor values. I designed a circuit-emulation of
hex-schmitt oscillator in synthedit, by plugging in VCC and v+ & V-
thresholds (found in datasheets), i can get fairly close
approximations of what freq's will result from cap + resistor
combinations.....I designed it so I could figure out the freq's used
for analog beatboxes cymbal & hihat tones just from schematics (i.e
808, 606, KPR-77, KR-55, cr-5000, cr-8000 etc.)

Seeya

RYan

--- In tr-707@yahoogroups.com , "gregory zifcak" <foleymachine@...> wrote:
>
> i'm not aware of anyone using schmitt chips, but according to ryan
> they should have fairly stable tuning if you use decoupling caps on
> the power supply. i would definitely try it out if i were you as it
> would be much less work to assemble, troubleshoot, and fit in the case
> than the bank of 555s. if you do try it out, be sure to let us know
> the results.
>
> --- In tr-707@yahoogroups.com , "thom uliasz" <dsl_tru@> wrote:
> >
> > Oh, you've called me outta my lurking with this subject..
> > I love the idea of multiple sample banks in the 707!
> > Id thought that the roms could not be read easily, and the data
> would come
> > out scrambled
> > Not an issue anymore
> > Id defintiely offer whatever sounds i could, ive got a few univox
drum
> > boxes. .analog - so no rom dumps. I could also offer a large
> assortment of
> > toy kit samples, sliced up break beats ans other useful samples.
> >
> > Has anyone gotten any conclusive pitch mod results using Schmitt
> triggers
> > Im just about ready to start the pitch mod in my 707, so alittle
> guidance
> > from the wise would be appreciated.
> >
> > And finally - does anyone have a schematic for the 626 Id like to
> attempt
> > the pitch/decay/input mods on mine. - Check out my 626 bending page
> while
> > your at it (third post down):
> > http://burnkit2600.com/gear/
> > -Thom
> >
>