Sunday, January 06, 2013

Hammond Tone Generator - Part 2

I have tested all the outputs of the Hammond tone generator. Some of the levels are lower than others, but all are generating output. The levels are too low to be switched by anything other than physical switches, so they must be amplified. Many of the tone generator (TG) outputs are filtered through a LC filter to suppress harmonics and reinforce the fundamental. If I were to bypass this filter, I would have higher levels from each of the TG outputs. Unfortunately, the harmonics are clearly audible without the filter, so the filters must be retained. The lowest 42 tones have resistance wire wound into the coils, which is required when the TG outputs are connected to the various busbars in the organ, but not necessary if I were to replicate the Hammond wiring scheme (61 keys x 9 wires per key = 549 wires per manual). I plan to use the TG in a more novel way, which has yet to be determined. The TG output levels can be increased by moving the core closer to the tone wheel, but external amplification will probably be required.

Friday, January 04, 2013

The amazing Deacy amp

Was listening to Queen's Greatest Hits and was looking up the band members on the internet. Turns out the bassist, John Deacon, was an electrical engineer. In the early days of the band, he FOUND a amplifier circuit board on the street and decided to try and make it useful. He put the amp in a spare speaker cabinet and the Deacy amp was born. In combination with May's Red Special guitar and a treble booster pedal, the classic Queen guitar sound was born. Expensive replicas have been built : that achieve 85% of the sound. :-)