Did you know you can control the speed (pitch) of a specific cassette player with control voltage from your analog synth? There's a cool bend of the GE Variable Speed Cassette Recorder by Chris Randall that lets you do just that. Unfortunately, and predictably, it doesn't track with normal 1v/Oct specifications of eurorack. This MIDI/CV converter fixes that and allows you to control the tape machine's pitch with MIDI, like a monophonic mellotron.
There are 2 versions of this device. This version, a Max for Live instrument which converts MIDI to CV, as well as a MIDI Effect which just converts the MIDI to the closest MIDI notes notes to be sent, through an external MIDI/CV converter, to the tape machine. If you don't have a DC coupled interface and instead have an external MIDI/CV converter you should use the MIDI version instead of this device. ( https://stevieschmidt.gumroad.com/l/fsdbX )
This device gives you 14 workable MIDI notes. The notes aren't perfectly in tune, but they are within a few cents. If you wanted perfect you probably wouldn't be using a modded cassette recorder and Max for Live to make music in the first place.
Low parameter chooses the lowest note of your range. (The highest note will be displayed next to it)
Re-trigger toggle, with options for last, low and high note priority.
Clip out of range notes or throw them away.
To have it work properly:
1) Turn the built in variable speed control on the cassette player all the way up for accurate pitch scaling. This knob changes the range of the CV input. When all the way down the CV in wont work at all.
2) If you haven't also done the Gemini Horror cassette mod, only the first 7 notes or so will work. Once that mod is added (and switched on) the rest of the range will open up as you lower the speed. I think as you lower the speed it opens up more room for the extra voltage, or something, I have no idea. Once you lower it too much though, because it can get ridiculously low, the scaling becomes inaccurate.
3) I've found the lowest note (0v) is the least stable. Once some voltage is being sent to the CV in, it becomes a lot more stable. So if you want to tune to something, I'd suggest using any note besides the lowest note to tune.
Tested with the GE-35367. I think it should work the same for all of the slightly different ones that look like it. If you could verify that the scaling works on your slightly different model that would be helpful!
Shout out to Gemini Horror and Chris Randall, for the bends! Also, maxforlive.com user Phatline, whose “Midi-Mono-ddg.mono 2” device was very very very slightly modified to make the retrigger on this device.
Chris Randall CV In Pitch Control Mod:
Gemini Horror Pitch Control Mod (necessary for full range):