246r Sequential voltage source - buchla format - part 2 build notes

These are my build notes for the Roman 246r 

It's a pretty big build ... as are many Buchlaesque  builds 

so I've decided to split the build notes into a few posts.

Part 1 of the build is here:

Roman 246r - Buchla Format - build notes 1

 

 below is board 2 

 

The module called officially the 246r sequential voltage source.

It's a Buchla format sequencer.

 These are just my personal build notes.

I'm not a pro technician. 

These pics and notes as just to help me trouble shoot should I run into any problems.

  

Dave Brown has an excellent page on his mods of a 246.

Ive decided to try this.

+ Modular synthesis

Stage CV Input

PCB2:
With 16 stages there are no unused gates with floating inputs.
Add a 100 pF capacitor across R65.

I added a ceramic 101 cap

 

 

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Stage CV Output Level

PCB2:
Change R294, R296, R298, and R317 to 330K.

 

Don't install C57, C58, C59, C61.

 

Replace R288, R289, R290, R307 with a link.

*photo

  

I did install the rest of the caps

0.1uF F1 - 

F38 38 CERAMIC 5MM LS 

581-SA105E104M

decoupling ?

Next the SMD caps

15uF 

C3, C64, C65, C66, C67 

5 TANTALUM SMD CASE D 

Mouser 74-TR3D156K035C0150

 

and the voltage regulator

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Stage Pulse Output Level

On PCB2:
Change R55, R61, R72, R78, R86, R92, R100, R106, R114, R120, R128, R134,

to 6.8k

Again on PCB 2 change

 R142, R148, R156, R162, R170, R176, R184, R190, R198, R204, R212, R218, 

to 6.8k

Finally,

Change on PCB 2

R226, R232, R240, R246, R254, R260, R268, R275 

to 6K8

(I'm using 6.81K 1% tolerance with all these changes)

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