.........................................Very tiny connections................
| The Modular Workshop |
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.........................................Very tiny connections................ |
This project is a personal project. As much as I'd like to release these pcb layouts designs for SDIY there are several issues;
Firstly there are many errors as this is a first time (and only time) build, layouts were done in a drawing program, not a circuit board layout program. Nothing has been updated or corrected except by cutting/moving traces and connections based on re-reading the schematics. No documentation by me for this exists.
Secondly I don't have Don Buchla's permission to release these versions (flawed or not).
Lastly, it's built, sounds great and I want to spend time playing music not updating hand written notes and documentation and layouts.
WHAT IS BEING BUILT
My version of the Buchla 259
- Left Board is Principle and Modulation Oscillators
- Right board is Symmetry, Timbre and Order Modulation
- Added octave switches
- Removed all Autotune and Remote Able/Disable circuitry
- Changed frequency response to 1 volt per octave
Other technical info regarding the build
Sorry there is no BOM, I was not that organized and began the project over 2 years ago so some bits are lost/not remembered :-)
- All original parts as per the available schematics were used, really the only part substitution is for the matched transistor pairs. I used SSM2210 and SSM2220. A Buchla tech suggested I try the Linear Systems LS331 and LS351. I did, but it didn't seem to make any difference that I could notice to tracking, modulation effects or timbre.
- When I planned the board I designed to use either the original LF13331's (which I unwisely did use - expensive and fragile) and an alternate layout for AG202 (?201s) for the electronic switches which was also suggested by a tech.
- I think the only other minor change was using the spare half of an unused opamp as a buffer for the sinewave before it goes to the timbre circuit.. The sine stayed cleaner this way.
- The original 259 requires a power supply of +/- 15volts and a small 5volt supply. I used a standard 3 pin 5 volt regular (beside the main board(s) to supply the 5 volts as LED supply, etc.
- CV response to 1 volt per octave, I looked thru my notes and couldn't find what I changed, but probably it would have just been making the resistor going to the kybd input a little larger in size than the original (R5, R110, - just noticed that the schematic doesn't list a value, so experiment so you can fine trim with the resistor and a trimmer to 1 v/oct,)
- I can supply the schematic for the octave switcher if anyone needs, but again it's pretty standard fare based on a tapped series resistor network and separate buffers for each VCO. The circuit provides 0, 1, 2, 3 ,4 volts. If I did this again I'd probably make the range lower say starting at -2 to +2 volts.
If you've got a specific technical question, I'll do my best to answer. But I 'm not an engineer.
Busses and Connections
1 - Keyboard CV, 2 -Internal modulation busses: AM, FM, Timbre, Phase Lock
The builder
David Leith - davidleith.com
A few "non-musical" audio samples of 259 module recorded with
Edirol R09 recorder and internal microphone
Messing around with all modulation and waveform options as well as phase lock..... :-D
Sample 1
Sample 2
Sample 3
Sample 4
Sample 5
Sample 6
Sample 7
