[sdiy] sequential multitrack schematics.

[harry bissell]

The ability to use CV to select waveforms is more to 'save' IC pins.

Its not real interesting to use the CV to switch dynamically... they don't
MIX, they switch.  You could use a CV to program the chip (recall from 
computer
with one DAC and multiple S/H like uhhh... every CEM or SSM synth thta 
ever was ?

Having a pot 'might' be useful... I'd suggest that a rotary switch or a 
couple of toggles
that produce the correct voltages might be a better interface. The pot 
would be fussy
and hard to mark the front panel... the switch points would probably not 
be easy to label...
no detents etc...

OTOH if you want to use an LFO to switch waveforms... then the pot would 
offer a lot
of variations and fine-tuning of sounds... its a ~feature~ then, not a 
bug. Only building it
will tell you for sure...

H^) harry


Cole Groff wrote:
> So... physically, how would I select the waveshape if I were to have
> this all laid out in front of me, on a front panel?
>
>
>
> On 9/26/06, harry bissell <harrybissell at prodigy.net> wrote:
>> Save you the trouble... the CV selects the waveform
>>
>> H^) harry
>>
>> Cole Groff wrote:
>> > I'll contact the fellow who made the interface.
>> >
>> > Do you see down towards the bottom, the "Wave Select CV."  And then
>> > farther down there is a 10K potentiometer.  I'm guessing the
>> > potentiometer selects the wave?
>> >
>> > Cole
>> >
>> > On 9/26/06, Altitude <Altitude at optrand.com> wrote:
>> >> Cole,
>> >>   without looking at the data sheet for the 3394 (which you will
>> >> probably
>> >> need to do), I'll guess that it the CV is divided into 4 ranges which
>> >> select
>> >> the waveform
>> >>
>> >> -----Original Message-----
>> >> From: owner-synth-diy at dropmix.xs4all.nl
>> >> [mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Cole Groff
>> >> Sent: Tuesday, September 26, 2006 10:49 PM
>> >> To: synth-diy at dropmix.xs4all.nl
>> >> Subject: Re: [sdiy] sequential multitrack schematics.
>> >>
>> >> Thanks Raph.  This looks really nice.
>> >>
>> >> What I don't understand about this interface, is how it selects which
>> >> wave
>> >> form to use.
>> >>
>> >> How do you do this?
>> >>
>> >> Cole
>> >>
>> >> On 9/26/06, Altitude <Altitude at optrand.com> wrote:
>> >> > No, its all analog goodness.
>> >> >
>> >> > Aaron Cram designed and interface for it for modular use:
>> >> >
>> >> > www.ori.org/~aaronc/synth/CEM3394_V2.pdf
>> >> >
>> >> > Don't go hacking apart a multitrak for parts if it still works, its
>> >> > still a cool synth :P
>> >> >
>> >> > Cheers,
>> >> > Raph
>> >> >
>> >> > -----Original Message-----
>> >> > From: Cole Groff [mailto:chonald at gmail.com]
>> >> > Sent: Tuesday, September 26, 2006 5:42 PM
>> >> > To: Altitude
>> >> > Subject: Re: [sdiy] sequential multitrack schematics.
>> >> >
>> >> > Does the CEM 3394 need a computer or microprocessor to control 
>> it?  Or
>> >> > can it be made into a synth module?
>> >> >
>> >> > On 9/26/06, Altitude <altitude at optrand.com> wrote:
>> >> > > They were all socketed on mine
>> >> > >
>> >> > >
>> >> > > __________________________________________
>> >> > > "Setting the RESONANCE to high level might prove interesting" -
>> >> > > Roland
>> >> > > SH-101 Manual
>> >> > >
>> >> > > www.no-ho.com
>> >> > > www.teknatural.com
>> >> > >
>> >> > >
>> >> > >
>> >> > > -----Original Message-----
>> >> > > From: owner-synth-diy at dropmix.xs4all.nl
>> >> > > [mailto:owner-synth-diy at dropmix.xs4all.nl] On Behalf Of Cole 
>> Groff
>> >> > > Sent: Tuesday, September 26, 2006 4:05 PM
>> >> > > To: synth-diy at dropmix.xs4all.nl
>> >> > > Subject: Re: [sdiy] sequential multitrack schematics.
>> >> > >
>> >> > > Thanks guys.
>> >> > >
>> >> > > On to my next questions:
>> >> > > How hard will it be to remove these CEM chips from the SCI's 
>> circiut
>> >> > board?
>> >> > >
>> >> > > Are there any precautions I should take, or special things I
>> >> should do?
>> >> > >
>> >> > > Cole
>> >> > >
>> >> > > On 9/26/06, Bob Weigel <sounddoctorin at imt.net> wrote:
>> >> > > > These are a great sounding little machine.  Most compact 
>> velocity
>> >> > > > sensitive poly analog that I know of. And yes it uses the 
>> CEM3394
>> >> > > > as does six-trak, Split-eight (still have one for sale here but
>> >> > > > it's so mint I'm waiting for the right buyer), and MAX as 
>> well as
>> >> > > > the Akai AX-60 and 73 as I recall.
>> >> > > >
>> >> > > > There is lots of info off my cu.imt.net/~sounddoctorin/synthtec
>> >> page.
>> >> > > > Just follow the logical links to SCI etc.  Also note that 
>> there is
>> >> > > > a design flaw in the machine which causes the battery to 
>> discharge
>> >> > > > in about a year and a half.  If you don't enjoy replacing
>> >> > > > batteries I can show you how to fix that.  Much...pain 
>> finding the
>> >> problem.
>> >> > > > Would never object to being tipped for the tip on that one.
>> >> > > >
>> >> > > > As far as I know there is no specific parameter edit on these
>> >> > > > machines but patches are small so dumping a patch is probably
>> >> how it's
>> >> done.
>> >> > -Bob
>> >> > > >
>> >> > > > Cole Groff wrote:
>> >> > > >
>> >> > > > > is there anywhere to find out what's inside a multitrack?  i
>> >> > > > > might have the opportunity to buy one from a friend.  i 
>> want to
>> >> > > > > know what's in there.
>> >> > > > >
>> >> > > > >
>> >> > > >
>> >> > >
>> >> > >
>> >> >
>> >> >
>> >>
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