Copyright 2020 by Synthetic Sound Labs LLC - 3650 Digital Sequencer
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APPENDIX
LED STATES
Throughout this manual, we will refer to the following four “states” of an LED light:
Off
Not lit
On
Lit continuously (steady)
Blink
Flashing on & off about 4 times per second
Flicker
Flashing on & off very rapidly
CALIBRATION
You can use the trim pot on the rear of the module to calibrate the sequencer to 1.2 volts per octave. You will
need a small jeweler’s screwdriver, either Philips or flat blade will do. The blade should fit comfortably into the
trim pot’s plastic adjustment to prevent damage.
CAUTION - You will need to remove the module from your rack while doing calibration, which means that you
must ensure that the module is safely isolated from short circuits. Laying the module on a cloth towel is a good
method. There are no dangerous voltages connected directly to the module, but there may be other safety
concerns within your rack that we cannot advise you on.
Though you shouldn’t have any problems if you are careful –
YOU AGREE TO PERFORM THIS PROCEDURE
ENTIRELY AT YOUR OWN RISK !!!
Procedure:
1.
Connect a voltmeter to the CV OUT jack of the sequencer you want to calibrate
2.
Press RESET to make sure the sequencer is in Ready or Program mode (either will work)
3.
Press the OCTAVE UP button a few times to set the keyboard to the highest octave (OCTAVE UP LED ON
steady)
4.
Press the NOTE C button
5.
Adjust the trim pot until the meter reads as close to 4.800V as you can get it
6.
Check the C notes on the lower octaves by pressing the OCTAVE DOWN then NOTE C buttons. Each one
should be an even voltage. If not, adjust the trim pot until they are as close as possible. Remember that
Buchla uses 1.2V per Octave.
C4 (Highest Octave)
4.800V
C3 (Higher Octave)
3.600V
C2 (Middle Octave)
2.400V
C1 (Lower Octave)
1.200V
C0 (Lowest Octave)
0.000V
The outputs of the sequencer are buffered, so they should maintain their voltages even when loaded down by
another module. You may find, however, that the standard calibration doesn’t work with certain modules. In
this case, you can use the trim pot to adjust the calibration so that it is correct for your module.
FACTORY RESET
If something goes terribly wrong or you simply want to wipe out your stored sequences and songs. Press and
hold the black C# and D# keys while you power up your synthesizer and wait for the light show to complete
once. You WILL lose all your songs and sequences!
