Vintage Synth Explorer Forums

Hi everyone,

A while back, I got the Korg Monotron (my first real analogue synth) and I really fell in love with how you controlled the pitch using a knob. I'm looking into getting the MFB Kraftzwerg as my next step up. I wanted to control the synth in a similar manner to how I controlled the Korg Monotron. I want to use knobs to control the pitch instead of keys. At first I was looking into midi controllers but I don't think the Kraftzwerg has it, it uses CV/Gate inputs. I was wondering how easy would it be to build my own custom CV/Gate controller for at synth? I did some research and saw CV/Gate uses 5V, with one volt per octave (at least one standard does). Could I just build something with 5V going through two pots, one with more resistance and one with less for a fine and course pitch control, then adding a kill switch at the end? I just learned about the existence of CV/Gates yesterday so forgive any ignorance

aeudet wrote:Hi everyone,

A while back, I got the Korg Monotron (my first real analogue synth) and I really fell in love with how you controlled the pitch using a knob. I'm looking into getting the MFB Kraftzwerg as my next step up. I wanted to control the synth in a similar manner to how I controlled the Korg Monotron. I want to use knobs to control the pitch instead of keys. At first I was looking into midi controllers but I don't think the Kraftzwerg has it, it uses CV/Gate inputs. I was wondering how easy would it be to build my own custom CV/Gate controller for at synth? I did some research and saw CV/Gate uses 5V, with one volt per octave (at least one standard does). Could I just build something with 5V going through two pots, one with more resistance and one with less for a fine and course pitch control, then adding a kill switch at the end? I just learned about the existence of CV/Gates yesterday so forgive any ignorance

It has midi too .

Yes, the Kraftzwerg has midi input, do a bit more research and you'd see this in a second.

The answer to your controller question is yes, except for the kill switch bit. If you switch off the CV signal the voltage drops to 0V which doesn't stop the note, it just drops it to the base pitch. What you want is two voltages, one to control the pitch via your knob arrangement and one wired through a switch for gate.

Press button, note goes on. Move knob, pitch changes. The kraftzwerg already has knobs for pitch, but it's a separate one for each VCO. Building a 'controller' like you said would let you control all three with one.

This sounds like something that would be pretty easy. For power, you could use a 9V battery, or use a wall wart that's in the 5V-10V range. For the pitch, use a 10K pot and a 1K pot (both linear) in series. With 9V power, the 1K pot would have a range of a little less than an octave.

For the gate, use a switch with a 1K resistor in series. You might want two switches in parallel -- a pushbutton and a toggle switch. The toggle is a "hold" switch; it lets you play long drones without having to keep your finger on the button.

Thanks a lot for the help guys, I really appreciate it

Just some clarification, so it's okay to send a 9V signal into the CV jack? I won't have to convert it down to 5V or anything?

Also, for the gate circuit, it doesn't require any power, correct?