hey greg!!!
Thats is good idea!!! U have to send me some pick of your
bend. For the m64-c cartridge i got some news... Roland will send me
the schematic of the cartridge. So we can figured out to upgrade
this thing!!! It will be post shortly may be in the middle of this
week.

For your upgrade of the chip 707/727 thats a pretty good idea and
pretty simple to do. I think of that, and why we not burning a new
sound on the rom Imagine!!! I look at some epprom burner to do this
but im not a expert in that. the only thing we have to figure is to
find a epprom like the 707(8 bit)i think! That will be heaven! If we
can create a box with a serial printer connector and change each
time u want the sound of 707!!!

So any expert in rom The part number of the ic is HN51256pc71.

regards
bizz



--- In tr-707@yahoogroups.com , gregory zifcak <foleymachine@y...>
wrote:

> my first message came back to me after all. here it
> is:
>
> thanks for starting this group, the 707 is the center
> of my
> operation. i will post info and instructions about
> mods as i do them.
>
> as for the mc64, cool idea. i can't help you out
> though, in fact i
> tore the whole slot out of mine to make room for some
> big switches to
> switch between the sounds of the 707 and 727. i'm
> planning to use
> switches from those big printer switcher boxes that
> switch between
> serial ports that have 25 pins. the voice roms for the
> 707/27 have 28
> pins. my plan is to put sockets where the voice roms
> are, then put
> the voice roms on a separate circuit board (with
> sockets), hook up +
> and gnd and pin 22 (called chip select) to the
> positions on the
> original board, then hook the remaining 25 pins to the
> 25 wires
> coming from one of the positions of the switch, and
> the two voice
> roms on the new board to the other 2 positions. i'm
> thinking maybe
> the easiest way to do the hookup is to find the right
> size ribbon to
> go between the sockets and the new board with the roms
> and switches.
> any opinions i'll definitely post my findings.
>
> other ideas:
> 1. since i have the decay mods and vca inputs, i'm
> thinking of also
> adding some kind of cv input or internal oscillator
> for amplitude
> modulation of the cymbal/hh/external sounds.
>
> 2. 808 oscillators. the 808 hihat, cymbal, and cowbell
> sounds are
> generated by a hex schmitt trigger chip that is wired
> as 6 squarewave
> oscillators, which are mixed with resistors and then
> filtered. my
> idea is to at least build the oscillator section (chip
> and a few
> resistors and capacitors) and see how it sounds, then
> maybe some
> simple bandpass filters with frequency knobs. then
> i'll plug them
> into my vca inputs so i've got 808hh/707hh,
> 808cy/707ride, and
> 808cowbell/707crash! the cool thing too is that you
> can tune the
> pitch of the oscillators by varying the power with a
> pot (5v max!). i
> don't know if this has any relevance for anyone
> because you need the
> decay/vca mod for this to be useful, but if you
> haven't done it i
> highly recommend it. i'll upload plutonique9's
> instructions from
> Analogue Heaven, as well as the 808 schematics. the
> modern day
> equivalent of the chip in the 808 is call 74hc14 hex
> schmitt trigger.
>
> 3. multiple trigger outs. this one i haven't quite
> figured out. i
> currently use the rimshot trigger to sequence an
> analog bass drum. i
> have a few other devices and 4 or 5 more trigger outs
> would be
> extremely useful! i have found the internal triggers
> in the 707, but
> they seem really low amplitude and maybe even negative
> going. i
> imagine this sort of thing can be done with a
> comparator otherwise,
> i'm going to try with a 555 configured as a fast
> one-shot. again,
> i'll post info when i try it out.
>
> greg
>
>
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