15-02-2023, 06:38 PM
(This post was last modified: 15-02-2023, 06:38 PM by Lucien Nunes.)
Yes, there is that. However at 44 years old this Yamaha has not needed a single capacitor replaced so far and still works 100% and sounds fantastic, so the cost and effort of a recap will be spread over half a century of use. Unlike the Wurlitzer that started this thread, the E50 has also escaped failure of any custom semiconductors, which are often the ultimate limiter of lifespan of these more modern instruments. By contrast the Wurlitzer is only still playing thanks to cannibalisation. It has had at least five custom or difficult-to-source ICs replaced so far.
The one that worries me most from the point of view of becoming irreparable through age-related deterioration is the Dereux. The rotary electrostatic generators are truly excellent with very high resolution photo-lithographed waveform traces, but they are intricate and fragile and there is some visible incipient debonding of the traces from the stators that I have not been able to investigate yet. It still plays fine, but I fear they might need to be dismantled and carefully scanned, then reassembled and played on an archive-quality audio recording to provide a permanent record of what this remarkable instrument was able to achieve. Because it's a materials stability issue, it's likely that once one starts to fail, they all will, and without a record as of now there might suddenly be no fully intact examples to use to re-construct unless some have been kept at consistently low and stable temperature which is likely to have assisted with survival.
See attached pics of the Dereux. Some aspects of the instrument are a bit basic and clunky, notably the playing surface which falls short of the fine, craftsman-built Comptons. But the tone generation, really the heart of the organ and the bit that sells it as a musical work of art, is impressive both from the methodology and the execution. The principle is very similar to the Compton, using proportional DC keying voltages to command from the generators the correct proportions of different waveforms. It does not rely on complete additive synthesis; there are complete pipe tones present as there are in the better Compton models. Also corresponding to the upper tier of Comptons there are some refinements, such as a breaking mixture, implemented in rather more streamlined ways (in this case by a diode matrix instead of a separate rank that breaks back) and a speaker with a rotating treble director (Compton and Allen both moved the drive units, Dereux moves only the diffuser.)
The generators are in a subchassis with six on each side, hanging on a spring inside the console. The cable looms run to 12 boards, one per generator, where voicing switches are operated by rods controlled via Bowden cables attached to the stopkeys. To maximise the SNR, this organ uses very high polarising voltages, 900V IIRC, so ones does not want to go poking around on those boards without one hand in the pocket.
The one that worries me most from the point of view of becoming irreparable through age-related deterioration is the Dereux. The rotary electrostatic generators are truly excellent with very high resolution photo-lithographed waveform traces, but they are intricate and fragile and there is some visible incipient debonding of the traces from the stators that I have not been able to investigate yet. It still plays fine, but I fear they might need to be dismantled and carefully scanned, then reassembled and played on an archive-quality audio recording to provide a permanent record of what this remarkable instrument was able to achieve. Because it's a materials stability issue, it's likely that once one starts to fail, they all will, and without a record as of now there might suddenly be no fully intact examples to use to re-construct unless some have been kept at consistently low and stable temperature which is likely to have assisted with survival.
See attached pics of the Dereux. Some aspects of the instrument are a bit basic and clunky, notably the playing surface which falls short of the fine, craftsman-built Comptons. But the tone generation, really the heart of the organ and the bit that sells it as a musical work of art, is impressive both from the methodology and the execution. The principle is very similar to the Compton, using proportional DC keying voltages to command from the generators the correct proportions of different waveforms. It does not rely on complete additive synthesis; there are complete pipe tones present as there are in the better Compton models. Also corresponding to the upper tier of Comptons there are some refinements, such as a breaking mixture, implemented in rather more streamlined ways (in this case by a diode matrix instead of a separate rank that breaks back) and a speaker with a rotating treble director (Compton and Allen both moved the drive units, Dereux moves only the diffuser.)
The generators are in a subchassis with six on each side, hanging on a spring inside the console. The cable looms run to 12 boards, one per generator, where voicing switches are operated by rods controlled via Bowden cables attached to the stopkeys. To maximise the SNR, this organ uses very high polarising voltages, 900V IIRC, so ones does not want to go poking around on those boards without one hand in the pocket.
