bizz,
yeah, that sounds super good! i don't know anything about eproms but
i definitely want to research it and see what i can find. i think
i've seen it mentioned on AH, i'll check the archives.
greg

--- In tr-707@yahoogroups.com , "bisaillon3" <bisaillon3@y...> wrote:
> 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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