Thu Jan 27, 2022 6:59 pm
The first time I modified my Rodgers 333 for Hauptwerk I kept the existing analog tone generation intact. The harnesses from the keyboards go to a keyer board on one of the wooden frames. You can solder wires on the PC board and run them to an encoder card. As stated by FrankEvans, the keying voltage is +12 volts, which can be used readily by many cards. I would suggest considering the DTS Midisystems encoders (you would have to order the HV version for positive keying). They are very simple to program using DIP switches.
The stop switch outputs also go to PC boards on the frame, but they are more widely dispersed than the keyboard outputs.
If you send me a personal message with your email, I can send you photos and a writeup of the procedure.
The other wrinkle is that you need to replace the potentiomenters on the swell shoes with dual ganged potentiometers - a 500 ohm for the LDR controlled audio, and a 5k or 10 linear pot for the midi encoder. I can give you the exact specification.
One wrinkle you will have is that the Rodgers analog circuits have no latency, and Hauptwerk has a varying degree of latency depending on buffer settings, the sound card driver, etc. You would have to fiddle the adjustments to minimize the latency, but even then there is likely to be a noticeable differential. If you just want to play only the analog stops or only the digital stops, it doesn't matter what the latency is.
Now having gone through all the tedium of keeping my organ intact, one day there was a power surge which blew the diodes in the power supply, and caused irreparable damage to the transposer time division multiplexing. This effectively killed the keying outputs to the midi encoders. So I totally gutted the analog electronics, rewired directly from the keyboard harness (which makes for a very neat job), and never looked back.
My initial reluctance to avoid gutting the original (and horribly expensive) electronics was overcome by the incredible difference between sampled sounds and the old analog tone generators. The Rodgers tone generation was excellent for its era (see the video of George Wright on Youtube playing the Robert Powers custom Rodgers).