From donstavely@msn.com Fri Jan 18 05:51:16 2013
Subject:Modern Analog Tonewheel Organ Project

Recall that several months ago I described my analog tonewheel organ project. I have made some good progress on it, so I wanted to give you all an update.

I now have the two main boards working. The first is the Tone Generator board, which produces the 91 sine signals at the precise frequencies of the Hammond gear ratios and tonewheels. The second is the Switch Matrix board, which switches the 91 tones to the nine drawbar busses based on the 61 key signals.

I recently added a MIDI decoder so I can use a standard keyboard to drive the tonewheel engine. This also allows me to use a MIDI sequencer to play a song, given that I am not a musician.

Take a listen to the files a uploaded to the Rigs folder. I think you will agree that it is starting to sound like a credible organ. I can "crudely" do the drawbar registrations (the 8's and 0's in the file name).

I am using my analog scanner C/V breadboard. It scans a 25-stage LC delay line, just like Hammond's. You hear it on both samples.

Please note that there is no percussion or tonewheel leakage yet – these will be added next. There is no final EQ or other fine tuning that will require careful comparison to a real Hammond. And of course I don't have Leslie emulation, reverb, and any other downstream effects.

With these caveats, I would love to get some early constructive feedback from you guys (and gals?) It is a big project, and I am going to need all the help I can get to make this a worthy modern clone.

Thanks,
Don