The project is getting very close to fruition. I've recently tested and now have working the VC Trigger Generator, Noise, Selective Inverter, Phase Shifter, Voltage Processing Module, and tonight, the Tuner Monitor. The Voltage Follower (slew or portamento), Ring Modulator, and Input Amplifier prototypes have shipped and should be here early next week. After that, I need to finish up some panels and then order some production PCBs.
Nyle came over last night and spent a few hours helping me go through the Selective Inverter. It is a very interesting module, and I don't quite know how to explain it. I guess because I'm still trying to understand it. It was a specialty module Nyle built for a customer and very few were every built.
Now, onto the keyboard. I'm starting with the duophonic keyboard. I've captured the schematic and will start the layout this weekend. I think I've got a way to easily use any new matrixed keybed or even a generic midi controller as an old single buss keybed.
First, Doepfer makes a DIY unit they call the MKE. It takes a Fatar matrix keybed and outputs the midi information like note on/off, velocity, etc.
Second, Doepfer also make a unit they call the MTC64. It converts midi note on/off to a TTL voltage for 64 notes. You can cascade two to get all 128 notes if you want.
Working backward, I can use the MTC64 and feed each TTL "switch" to a solid state relay or even a reed switch relay. That relay becomes the switch for the buss. I can then build the resistor ladder down this series of relays and I got a single buss, 61 note keybed that is just waiting for midi note on/off messages. the cool thing about this system is it is now a general purpose midi to Steiner Duo-Phonic CV generator. You can plug anything which generates midi note on/off signals. Nyle saw he could plug his EVI midi out into such a controller to play his modular when he gets it built.
The next step will be to take a Fatar 61 note keybed and using the MKE, build a cool looking keyboard. In reality, I can just use my Synthesizers.com keyboard.
I'm thinking I'll build the keyboard electronics with relays and MTC64 into its own box. It will have wheels, thanks to Synthwood, for portamento and pitch bend as well as the other knobs for tuning and scale. There will be a companion panel for the modular which will connect this "module" and make the various outputs available. I'm really liking this little find I made on the Doepfer web site.
OK for now. I should have a bit of a breather from work next week. I still really want to put together some video of the modules. Nyle is offering to help make them which I think is great!
The web site has had a bunch of updates in the last month or so. Have a look.