Pianocorder Information
By Jody Kravitz
Mike Jardin asked some questions about the Pianocorder. First, I'm curious where Mike is getting the parts. I don't believe these have not been in production for a long time. There's a lot of these systems in the LA area maintained by a technician who bought the rights to use the DBA Universal Piano Co. His name is Randy Cox and he can be reached at 714-283-4242.
I cannot speak for the mechanical difficulty of installing one of these systems (talk to Randy), but I've had some experience with the electronics. The most notable point w/r/t the electronics is that it structured very similarly to pneumatic reproducing pianos. In particular, there are two D/A converters for expression control -- one for the bass cleff and one for the treble cleff. I don't recall there being any support for cresendos, just discreet levels. I don't remember if there are 3 or 4 bits going to each converter. This arrangement makes transcribing pneumatic rolls into Pianocorder format straightforward (except for the cresendo issue), but it makes the MIDI conversion a problem because MIDI assigns a velocity value to EACH note. It is possible to play notes in the base and treble cleff simultaneously with differrent velocities, it is not possible to play notes in the same cleff simultaneously with differrent velocities. This makes the job of the MIDI converter box hard.
Frankly, this also makes conversion of MIDI performances to pneumatic reproducing piano format difficult as well. Mike Ames has made an Ampico A available to me for experiments in this area, but there's only so much time in the day...
A word of caution w/r/t the Pianocorder's electronics (and probably some of the other systems which I've not seen the insides of yet). The Pianocorder systems I've seen did NOT have isolation transformers. This results in the possibility of line voltage to be present where you think there should be "ground", including wiring to the cassette recorder. They use plastic knobs for a reason!
I've only seen (and tried) one commercial MIDI converter design for the Pianocorder. It worked pretty well and _seemed_ to have the necessary circuit isolation. I talked to the engineer that designed it a couple of years ago. It turns out that he's the same engineer that designed the Pianomation electronics for QRS.
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Mechanical
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