[sdiy] components, smd and pcb

[Tony Clark]

> No, not at all. I have simplified the oscillator circuits. For one VCO
> + 4 octave saw dividers + 4 octaves transpose circuit + triangle / pulse
> waveshapers I only need this:
> 
> 1 CD4520 (the two dividers)
> 7 bipolar transistors (VCO core and waveshapers)
> 1 CD4066 (transpose switches)
> 1 TL084 (replaces all the selected SK30's in the original, and most
>                 of the coupling capacitors)
> 1 FET (unselected)

   Wow, that seems very minimalistic.  The reason I was inquiring is that 
one of the top-octave divider chips is bad on a 3100 I'm restoring and 
I'm always in the lookout for a replacement that doesn't involve obsolete 
and hard to find parts.
   I'm guessing that you are using a pulse to saw converter for each 
output, so I'm curious as to how stable the amplitude outputs will be as 
the frequency of the core is shifted?  Or are you not worrying about 
that?

> While it's not compatible to an original PS-3100, the good thing is that
> it will go on standard double europa cards with two DIN41612 connectors
> which are mounted into a 19" 6U rack frame. So building more than one
> will be not entirely impossible this time.

   Very nice!

> But it's all just in the very beginning. I will first build one VCO card
> (6VCOs), and see what it costs and how good it works. Then I'll decide
> wheter to cancel it all, to build a second card (PS-3100), or to build
> three more cards (and go for PS-3200).

   Why not go for 5 more cards and have the grand-daddy PS-3300?!

> If I say "PS-something", I just mean the general route. 2 oscillators
> per voice will not mean patch storage, nor the lack of a 3100's
> resonators. I still have to decide if I'm using the original ADSRs
> or something of my own, for instance.

   Well whatever you decide to do, I know it will be a fantastic piece of 
engineering and work when you are through!

> Just in case I would really go for patch storage (gladly, I don't have
> to make that decision now; it can be added later) -
> Dou you know a source for 10k lin pull-pots ?

   Unfortunately, no.  Specialty pots and switches are some of the 
hardest things to track down.  :(  Good luck to you in finding them!
   And keep us posted on your progress!  ;)

   Cheers,

   Tony

-----------------------------------------------------------------------
         The E-Music DIY Archive - New Site Coming Soon!
-----------------------------------------------------------------------

"We wouldn't want to ship something that doesn't work"
   - Carl Stork, general manager, Microsoft Windows division
     Excerpt from EE Times April 2, 2001