[sdiy] 100K pot in Music Easel timbre section, and board setup

[mark verbos]

On Nov 23, 2008, at 4:35 PM, Aaron Lanterman wrote:

> Hello keepers of the knowledge of Buchla:
>
> 1) If you look here, you'll find the "timbre" generating circuitry  
> of the Music Easel:
>
> http://rubidium.dyndns.org/~magnus/synths/companies/buchla/ 
> Buchla_2080_9_200.jpg
>
> In the lower part of the schematic, there's a 100K pot, which runs  
> from the collector of Q5 go ground, with the wiper going to the  
> gate of Q6 through a 10K resistor.
>
> Is this pot on the front panel, or is it a trim pot of some sort on  
> the circuit board?

It's a trim pot of some sort. It sets the timbre control range.


>
> 2) If you look here, you'll find a set of diagrams describing how  
> the various boards connect to each other:
>
> http://rubidium.dyndns.org/~magnus/synths/companies/buchla/ 
> Buchla_2080_13A_200.jpg
> http://rubidium.dyndns.org/~magnus/synths/companies/buchla/ 
> Buchla_2080_13B_200.jpg
> http://rubidium.dyndns.org/~magnus/synths/companies/buchla/ 
> Buchla_2080_14A_200.jpg
> http://rubidium.dyndns.org/~magnus/synths/companies/buchla/ 
> Buchla_2080_14B_200.jpg
>
> Is there a "master key" of what the various S1 and S2 marking along  
> the top and bottom of the pages correspond to? I'm sure with a lot  
> of detective work I could puzzle it out - I was just wondering if  
> there was a known list somewhere.
>

S1 is the 56 pin edge card connector on the front panel. S2 and S3  
are 16 pin DIP connector ribbon cables that go to the jacks on the  
front panel. It's easy to see what they are if you look at where  
they're coming from.

Mark