My suggestion is to just go for the hats (cowbell is ez too)....the
808 cymbal & handlclap are the most complicated drum circuits in the
machine. The cymbals use like 3 or 4 diferent filters & envelopes &
vca's mixed together, it wouldn't sound convincing without going the
full distance.

Build two twin-t bandpass filters from single dual opamp (one for hats
other for cowbell), and a single transistor HPF (simple to
make).....the transistor HPF is key to the hats, it's got a real
strong cutoff and transistors by nature and saturation (extra harmonics).

Probably don't have to build the VCA, but if you did...it's basically
a diode with a RC envelope.

Seeya

Ryan

--- In tr-707@yahoogroups.com , "gregory zifcak" <foleymachine@...> wrote:
>
> nice! thanks for the valuable info. i'm still thinking about building
> one of these for analog hats and cymbals. do you think a couple
> bandpass filters would suffice for some nice sounds (i know it would
> be no 808)
>
> --- In tr-707@yahoogroups.com , "plutoniq9" <Plutonique9@> wrote:
> >
> > 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
> > > >
> > >
> >
>