Do you know which IC is responsible for routing between interleaved
sounds I have a dead 707 that first stopped routing, so that it
worked great except that there was no rimshot, both rim/cow played
cow and so on, although the sound sets sequenced normally.

--- In tr-707@yahoogroups.com , "plutoniq9" <Plutonique9@...> wrote:
>
> Eprom's, like all parallel memory, addresses it's memory in binary
> format. Think of the address lines as being binary inputs....for
every
> address line you add, like binary, doubles the amount of locations
> (numbers) it can access. Inside the memory, the address pins are
> decoded to select different areas of the memory.
>
> 1 address lines = 1bit :: 2 values (memory locations)
> 2 address lines = 2bit :: 4 values (memory locations)
> 3 address lines = 3bit :: 8 values (memory locations)
> 4 address lines = 4bit :: 16 values (memory locations)
> 5 address lines = 5bit :: 32 values (memory locations)
> 6 address lines = 6bit :: 64 values (memory locations)
> 7 address lines = 7bit :: 128 values (memory locations)
> 8 address lines = 8bit :: 256 values (memory locations)
>
> and so forth.....
>
> So, imagine you have a 32k X 8-bit eprom, that would require 15
> address-lines (32,768 memory locations)...that is what the size of
> each eprom is in the 707/727. If you wanted to double your memory
> (sample banks) would only require an addition address line (each
> address line doubles memory that can be accessed)....seeing as
address
> lines are just binary inputs, you can see how it would be easy to
add
> a single switch to toggle on/off (+5v, 0v) that extra address line
to
> switch between your (now) 2 banks of memory.
>
> That's what circuit bending is all about, they cross (short)
address
> lines which causes errors in the memory location access, which
cause
> the glitch sound....
>
> So, the way the 707 samples are interleaved in memory are just
> organized in a linear way (just like a mono recording), one sound
> after another. But what has stopped all the eprom hackers from
going
> ahead with new samples for these machines (unlike drumulator or dmx
> for example) is that the sounds (like BD1 & BD2) are intereleaved,
and
> they've been too lazy or unimaginative to proceed, saying "it's
> impossible" and hopeless shite like that :) Intereleaved sounds,
think
> of 'em like this;
>
> BD1 sample1 -> BD2 sample1 -> BD1 sample2 -> BD2 sample2 -> etc.
>
> after all of the BD samples are over the next sample set follows
> (interleaved)
>
> SD1 sample1 -> SD2 sample1 -> SD1 sample2 -> SD2 sample2 -> etc.
>
> Pretty simple heh :)
>
> I taught myself some C++ basics through online tutorials, though
> because i do audio DSP, i use the Synthedit SDK to develop stuff,
> which is a great platform. Check out these sites;
>
> http://www.cee.hw.ac.uk/~pjbk/pathways/cpp1/cpp1.html
>
> http://www.cprogramming.com/
>
> http://www.cplusplus.com/doc/tutorial/
>
> That should get ya started
>
> Seeya
>
> Ryan
>
>
> --- In tr-707@yahoogroups.com , "acousmatique" <acousmatique@>
wrote:
> >
> > --- In tr-707@yahoogroups.com , "plutoniq9" <Plutonique9@> wrote:
> > >
> > > According to the service manual, they are interleaved quite
> > > simply.....sounds that are shared (ie. BD1 & BD2) have occupy
the same
> > > adreesses, except one has even adresses & one has odd....you'd
have to
> > > write a small application that would organize new samples in
this
> > > way....but it's a simple routine & probably within my C++
scope.
> >
> > Arg... This is where my understanding of digital drum machines
has
> fallen apart! I have
> > read quite a few tutorials on EPROM addressing, and I still
doubt if
> I get it. Maybe I'm
> > thick! Also I have no C or C++ experience. Any advice on
how/where I
> can learn about
> > coding for low-level stuff like this Or even what key words I
might
> want to search for
> > Happy it's within *your* scope, anyway! >;]P
> >
> > CJ
> >
>