It was just over three years ago. The date on the tag says January 2018. I think it was early Feb before we got it home. These things do show up on Ebay, and the musical instrument sites like Reverb.com, but they are usually beat up and go for $100 to $200. Weighing in at 250 pounds limits the sale prospects a bit.
This one had been in the Goodwill store for a couple weeks. We went there in a car on our monthly drive to Pennsylvania to hit Sam's Club, Trader Joes, and Whole Foods. There are several thrift stores on the route. When I saw it I immediately bought it and arranged for me to return later with a van to pick it up.
I went back a few days later and the guy who helped me stuff it in my Honda Element said that he had some of his friends over one night after the manager had gone home. The organ worked fine and the power cord was intact and carefully stuffed in behind the amp chassis out of the managers site.
Very impressive geek resume, TL.
And wow, SWTPC brings back memories. I made a Plastic Tiger amp, which I later blew up working on a speaker project (not tolerant of output shorts, I learned). I also made the Theremin kit. Good times.
Obviously, my clonewheel project was much more recent, so I had full 74HC and quad op amp technology as my disposal. I have a theory that Hammond's close-but-not-exact equal temperament tuning is important to the authentic Hammond sound - the particular "beat" or warble on chords that aren't perfect intervals. So I exactly recreate his gear trains with 8-bit dividers and multipliers (PLL+divider). For example, he generates A-440Hz starting from a 20rps shaft, with an 88-tooth gear driving a 64-tooth gear to drive the "A shaft", which has tonewheels of 2, 4, 8, 16, 32, 64, and 128 teeth. The 16-tooth tonewheel is 440Hz. I start with a 3.7268MHz crystal divided by 20 for a 163.84KHz master clock. For 440Hz, I multiply by 64 and divide by 88 to drive the "A octave divider", and the /512 output is 440Hz.
I used individually tuned 2nd-order Sallen-Key filters to get to the 96 sine waves - what a PITA. Unfortunately, on testing the system I still heard a little residual 3rd harmonic in the tones, which is unauthentic-sounding. (It needs to be more than 40dB below the fundamental.) I shelved the project after redesigning the board with 3rd-order filters. Sigh.
Still, I am pretty proud of how it sounds. I attached a sound clip of the system driven by a MIDI sequence, including the LC delay line chorus.
I agree that 16-bit resolution is fine for audio, under well-controlled conditions - i.e. when your audio signal can take full advantage of all 16 bits. This is certainly the case for self-generated signals on a synth, and for mastered music on a CD. Any kind of audio-in audio-out effects box should have more dynamic range in order to handle less predictable input signal levels, IMO.
And wow, SWTPC brings back memories. I made a Plastic Tiger amp, which I later blew up working on a speaker project (not tolerant of output shorts, I learned). I also made the Theremin kit. Good times.
Obviously, my clonewheel project was much more recent, so I had full 74HC and quad op amp technology as my disposal. I have a theory that Hammond's close-but-not-exact equal temperament tuning is important to the authentic Hammond sound - the particular "beat" or warble on chords that aren't perfect intervals. So I exactly recreate his gear trains with 8-bit dividers and multipliers (PLL+divider). For example, he generates A-440Hz starting from a 20rps shaft, with an 88-tooth gear driving a 64-tooth gear to drive the "A shaft", which has tonewheels of 2, 4, 8, 16, 32, 64, and 128 teeth. The 16-tooth tonewheel is 440Hz. I start with a 3.7268MHz crystal divided by 20 for a 163.84KHz master clock. For 440Hz, I multiply by 64 and divide by 88 to drive the "A octave divider", and the /512 output is 440Hz.
I used individually tuned 2nd-order Sallen-Key filters to get to the 96 sine waves - what a PITA. Unfortunately, on testing the system I still heard a little residual 3rd harmonic in the tones, which is unauthentic-sounding. (It needs to be more than 40dB below the fundamental.) I shelved the project after redesigning the board with 3rd-order filters. Sigh.
Still, I am pretty proud of how it sounds. I attached a sound clip of the system driven by a MIDI sequence, including the LC delay line chorus.
I agree that 16-bit resolution is fine for audio, under well-controlled conditions - i.e. when your audio signal can take full advantage of all 16 bits. This is certainly the case for self-generated signals on a synth, and for mastered music on a CD. Any kind of audio-in audio-out effects box should have more dynamic range in order to handle less predictable input signal levels, IMO.
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