SixTrak 6-Output Modification?

[mariano elizalde]

Just to inform you all... ( I goofed on my previous attempt to send posts to
the list )

I will install the individual output for the SC sixtrak I have here to
anyone Sixtrak's who is near this city  ( Dallas, TX ) for free just to
finish the project I started looong ago ( I don't have a Sixtrak anymore...
:(  :( 

also, my current email address is ixcoatl at geocities.com  should I help anyone...

 ( I never worked for SC, wish I had......)




-----Original Message-----
From: media at mail1.nai.net <media at mail1.nai.net>
To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
Date: Tuesday, April 14, 1998 5:12 PM
Subject: Re: SixTrak 6-Output Modification?


>At 8:24 AM -0700 04/14/98, Fitzhugh, Karl wrote:
>>Anyone have any details on the 6-output modification for a SCI SixTrak?
>>I've seen mention of it on this list, and elsewhere on the net, but
>>can't seem to find any actual details on it. Basically I'm looking for
>>plain and simple instructions on how to do it - I'm not exactly an
>>expert at this sort of thing!
>>Hope someone can help, or point me in the right direction - thanks in
>>advance.
>
>Even though this might sound contrary to the spirit of synth-diy, imho, the
>right direction would be to moving away from performing such a mod.
>
>The first modification of this type was developed by Christopher "Litho"
>Jones.  Perhaps you can still find it at:
>
>http://mcjones-mac.wca.ohio-state.edu/self-oscillator
>
>It basically hacked an output directly from each 3394 chip.  Not only does
>this rely dangerously on the input impedance of an external device, it
>doesn't jive with the little I know about CEM 3394's.  As far as I know,
>the output is expressed as a current not a voltage.
>
>A much better modification was later developed by some guy whose address
>was elizalde at internetconnect.net.  Word on the street was that he used to
>work for Sequential Circuits.  Try pointing your browser to:
>
>http://www.geocities.com/SoHo/8047/sixtrak.htm
>
>This addressed the 
impedance levels and autotuning noise ignored by the
>Litho mods.  Otoh, it also required building another PCB and separate power
>supply!!
>
>I own a Six Trak myself.  It's a nice synth, but do not think it is worth
>all of the work and risk involved in adding an individual output for each
>voice.  The sound of a lone 3394 isn't that amazing.  I find that I mostly
>use my Six Trak in stack or unison mode.
>
>There is no easy way to add separate outs to a Six Trak -- the simple way
>is dangerous and the safe way is complicated.   Remember, this is an old
>digitally  controlled synth.  SCI and Curtis both went out of business and
>it is difficult to get parts if something goes wrong.
>
>PEACE OUT :)
>MARK
>
>
>
>