In addition to the filter CV out, the newer Modysix models feature a second CV output. It can be used for various tasks such as pitch bend, resonance control, pulse width control,…
Please note: In any case additional resistors and some soldering skill is needed to interface the CV out to your Synthesizer.This is not an official feature of the Modysix, but rather a little bonus to the already vast set of features, so please do not expect the same amount of support from Tubbutec. If you found an interesting application and want to share it with other Modysix users, please use the comment section below or send us an email.
Does my Modysix have a second CV out?
Your Modysix has a secon CV out, if there is a red wire alongside the orange filter wire.
The CV out is capable of an output voltage from 0 to 5V with a default voltage of 2.5V at start up. It is actually a PWM modulated signal, which has to be filtered, but this is already done in the Synthesizers circuitry or can easily be added. More about this later.
The CV responds to pitch bend commands and newer models also to controller number 21.
Pitch bend for Polysix
In order to add midi controlled pitch bend to your Polysix you need two resistors, one 68k one 34k. Other values are also possible, as long as one has double the value of the other. This will change the maximum pitch bend range. Smaller values will increase the range.
Depending on resistor tolerances and actual value of the -5V rail, the overall pitch might change a little, when installing this. You can correct this with the pitch knob or by replacing R2 with a 100k trimmer.
Figure 2 shows part of the Polysix schematic including the pitch bend (R9) and resonance R13 injection points. This is board KLM 367.
Polysix resonance control
Same circuit as for the pitch bend above, but connect it to R13. You might want to add a 100nF capacitor in parallel to R14 to filter the PWM signal. This gives you a bipolar resonance control.
More possible applications of the 2nd CV out will be added soon…