i didn't have any decoupling, likely the reason. if anyone is about to
try this mod, please try the hex schmitt! really would be a lot
simpler and more compact. no way, i love the 808 cowbell!

--- In tr-707@yahoogroups.com , "plutoniq9" <Plutonique9@...> wrote:
>
> Hi Gregory
>
> Actually, I just built the oscillators in a small external box with 6
> pots for tuning....from there i just modified the 808 so you could run
> external sounds through its hats/cymbal/cb circuitry....which would
> cut the internal hex oscillators (they are at the beginnning of the
> chain).
>
> They shouldn't have any affect on one another if you give the ic a
> well regulated power supply, did you add a largish electronic capitor
> connected to it's power pin & ground (de-coupling)
>
> Mine were stable enough that i could tune 'em all together or to make
> chords, but tuning got hard at the high range (very sensitive)....if i
> was to do it again i'd probably use multi-turn pots for better freq.
> control.
>
> From what i've read, you have 9 555 clocks If that was the case,
> there would be a need for 2 hex inverter IC's, maybe one could form a
> cowbell out of the remaining two oscillators :) Only joking, cowbell
sux..
>
> Seeya
>
> Ryan
> --- In tr-707@yahoogroups.com , "gregory zifcak" <foleymachine@> wrote:
> >
> > i actually tried this before i did the 555s. i had the hex schmitt
> > chips because i was following your 808 reports on AH and hoping to
> > build a version of the hh, cy and cb circuit (still gonna do it!). for
> > some reason, the individual pitch controls of the schmitt oscillators
> > interfered with each other quite a lot. if i remember correctly they
> > were soft-syncing each other so raising one pitch would raise others
> > with it. didn't you do individual pitch controls for the hex schmitt
> > in an 808 did you see this behavior it would definitely be an
> > attractive solution if someone could get it to work. much more elegant
> > than a s-load of 555s.
> >
> > --- In tr-707@yahoogroups.com , "plutoniq9" <Plutonique9@> wrote:
> > >
> > > I wonder if you could substitute a single Hex Schmitt-Trigger IC
(i.e
> > > CD4069) to produce the clocks instead of 555's, as you can form 6
> > > oscillators from a single chip.....with minimal external parts (1
> > > capacitor + 1 pot per clock), you could easily build it on one of
> > > those mini RS pcb boards. The formula for freq is in the datasheets.
> > >
> > > Just a thought
> > >
> > > ryan
> > >
> > > --- In tr-707@yahoogroups.com , "gregory zifcak" <foleymachine@>
wrote:
> > > >
> > > > well, i don't think it matters what kind of caps you use for
> 555s and
> > > > decay envelopes. i've had them work fine with polarized
> electrolytics
> > > > and ceramics.
> > > >
> > > > as far as the clocks, mine dip down into the audio range at their
> > > > lower end. you should be able to hear a faint whine if you touch
> their
> > > > outputs to the 707 outputs. if you can hear output, they
should work
> > > > as clocks. accordingly, you can use these clock circuits as audio
> > > > oscillators if you use a bigger cap. there is a free dos program
> > > > called 555.exe which calculates the frequency of the
oscillator when
> > > > you type in the values of the cap and resistor.
> > > >
> > > > --- In tr-707@yahoogroups.com , "philo_707" <philo_707@> wrote:
> > > > >
> > > > >
> > > > > Hmm, I'm def. a little confused about this one. I know the
> 555s I'm
> > > > > using are right, I followed the schematic posted here except for
> > > > > changing the resistor and cap values to the ones mentioned that
> > work,
> > > > > but no go yet. Would any .1 uf cap work
> > > > >
> > > > > For that matter, on the decay mod, will any 1.0-10 uF cap
> replacing
> > > > > the stock ones work Do they need to be electrolytic or non, or
> > does
> > > > > it really matter
> > > > >
> > > > > About the LCD, I bought a dead parts unit that probably has a
> > good LCD
> > > > > on it, so even if I am successful in my attempts to revive the
> fried
> > > > > one, I may have one nonetheless.
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > --- In tr-707@yahoogroups.com , "Bart Provoost" <bart@> wrote:
> > > > > >
> > > > > > >
> > > > > > > To the guy who needed an LCD, I'm still doing repairs,
but it
> > > looks
> > > > > > > like I will likely have a extra working LCD anyway,
we'll see.
> > > > > >
> > > > > >
> > > > > > That's interesting ;)
> > > > > >
> > > > > > Bart
> > > > > >
> > > > >
> > > >
> > >
> >
>