The 208 ToolBox and BOB expander
Add new inputs and outputs to your Music Easel easily and expand its potential without any modification.
Just plug, play and explore new deepnesses within your Easel. It couldn't be more simple.
The 208 ToolBox and BOB expander work with
- 208p, 208r rev2, 208r rev 2.1
- Vintage Buchla & Associates 208 and Music Easel
- BEMI / Buchla USA 208e and Music Easel
- Buchla USA 208c and Easel Command
They do NOT work with the 208r rev1 clone, the card slot pinout is not compatible, do not attempt.
Standard features :
- gold plated connector
- envelope times variable CV inputs with sliders
- switchable envelope looper with a pot delaying the retrig (like the "off" on Synthi, max delay time is about 7 sec) with CV input, a LED shows the retrig pulse signal
- envelope trigger banana input (the socket is shared with the looper delay CV input, selection with internal switch)
- gate to trigger converter circuit to have the envelope working in transient mode with any pulse (can be bypassed if desired)
- CO waveshape amplitude variable CV input with pot
- CO waveshape switch CV
- MO hi/mid/lo range switch with multiturn trimmer allowing accurate transpose
- MO waveshape switch CV
- sequencer 2 stages or CV input switch
- individual gate output for each sequencer stage
- trigger output for all sequencer stages activated with the 208's pulse sequence switches
- random trigger input
- 2 way CV mixer with attenuverters and a LED for level display, a 3rd input can be added
- optional rear female edge connector to connect a program card, iProgram card, Easel Aux Card or other modules to come
- 3 unused emplacements in the top left corner for banana, switch, tinijax, minijack... and perfboard on the PCB to add other features and match each one's own needs, the "to prog" panel sockets can be used as well of course, up to 5 custom connections and extra circuits are possible
Optional features examples :
Feel free to ask for other options you have in mind. Reverb mix and outputs levels cannot be controlled via the 208 ToolBox, these settings are not voltage controllable in the 208's original design.
All routing options together are possible thanks to the BOB expander.
It can be plugged into the ToolBox's rear edge connector or standalone into the 208.
The BOB expander has its own optional rear female connector to host the ToolBox plugged horizontally (an extra support is recommended to relieve the edge connector) or other card.
Overview - many thanks to Bill Sequeira
Standard features :
- 3 customisable places with perfboard like on the ToolBox
- sequencer pulse in
- pulser pulse in
- pulser trig out (a short trig, not the ramp available on yellow sockets)
- envelope trigger out
- envelope inverted out
- MO modulation switch CV
- LPG1 mode switch CV
- LPG2 mode switch CV
- LPG2 signal routing switch CV
How to get your 208 ToolBox or BOB expander ?
- Contact me for a custom built unit, price is 420 EUR for a ToolBox and 140 EUR for a BOB expander, optional features, VAT and shipping not included.
- DIY PCB sets and kits are available from
SAmodular (Germany) or SynthCube (US).
I no longer sell retail PCB sets myself but you're welcome to contact me for orders of 10 sets or more.
Docs and support
Please doublecheck that the BOM and build notes you have are the latest revision and match your PCB revision.
Thanks for looking and have fun with your expanded 208 !
I assume no liability for personal injury or damage to equipment or loss of use caused directly or indirectly by the use of the 208 ToolBox and BOB expanders.
Although 100% safe with any 208, the 218e and any other 200e modules could be damaged if you send an audio signal or a negative CV to a CV or pulse input banana.
The ToolBox's CV mixer and BOB expander's envelope inverter are able to output negative CV therefore do not patch these to a 200e module.
A schottky diode added in series with the 218e or other 200e module's input bananas is a straightforward easy to DIY protection from accidental negative CV / audio patching.
If you have a question or problem, please first check the FAQ before contacting me.
The DIY solutions are for experienced people able to read and understand the build notes, to solder neatly and to troubleshoot their own build. Circuits on the perfboard should be built only by those experienced in electronics. A wrong build or connection might cause serious damage to your instrument in a very short time.
Although I'm happy to help, I can't offer free support on all issues. Please understand remote troubleshooting of a wrong build can be difficult and time consuming. In case of unsolvable problem, I could accept to service your unit if it's shipped to me.
I'm constantly improving my designs taking into consideration the users feedbacks or my own experience and some changes might occur without notice and can't be subject to complaint. I'm happy to answer any question, feel free to ask before ordering.
The pics are for illustration purpose only and the actual units can vary according to the options.