> Whats with all the little transformers up top? Or are they chokes?
Where do notes come from? Guitars have strings. Harmonicas have reeds. Pipe-organs have pipes. Hammond has spinning tooth-wheels.
Electronic organs use oscillators.
They could run 32-90 oscillators one-per-note. That's almost as bad as a piano, worse because audio oscillators drift more than good pianos, even worse because the idea was to sell to ordinary people who couldn't tune a guitar, much less a piano.
There is a short-cut. Octave is simple 2:1. If you have a high A, you can get the A an octave down with a simple astable, and it WILL be same-pitch an octave lower. So you build a "top octave", twelve oscillators A thru G with semitones. Then you have 12 dividers per lower octave, maybe 8 octaves total so one oscillator and 7 dividers per note. The higher pitch top oscillator will tend to be more stable than lower audio frequency oscillators. Since there's only 12, you can build them extra good. When tuning is needed, there's just 12 screws for the whole instrument (little more than a guitar, far less than the 150-190 pins on a piano) so the tuning doesn't take a whole hour.
I'm not sure how this one is organ-ized. There's 9 modules with 6 bottles each. I'd expect 12 of something, and surely more than 6 octaves available (even if the manual is 3-octave, the stops let you layer different intervals on the same keys).
> How does the sound get out of the organ? And how does it compete with those 12" speakers?
In a classic pipe organ there is a box several feet wide, filled with pipes. The side facing the room has doors or shutters that open/close via a foot-pedal. Same as the go-pedal in your car opens the throttle-flap in the engine, only much bigger. Door open, the pipe sound goes mostly into the room. (Yes, phase is incoherent but so what?) Door closed, the sound is much softer. "Swell" is opening the doors during a musical passage. Tremolo is when you shimmy the swell pedal.
It seems this is the same idea on two 5" speakers in a 6-inch box. A small swell chest's doors need a strong leg, a big church-organ needs power assisted swell pedal; obviously this little flap could be worked directly with a small child's foot.
But then why, having a swell-chest, didn't they gimmick a tremolo motor to the swell-flap? More control of rate and depth? Cheaper?
> how does it compete with those 12" speakers?
The Fives are very efficient. The Twelves trade sensitivity for extended bass.
Also an organ "knows" where each note comes from. To over-simplify: notes from the left hand are low and sound through mellow filters to the 30 Watt and Twelves. Notes from the right hand are mid-high and sound through the 14 Watt and Fives. Two separate instruments. In many organ passages, the Twelves just loaf; but you gotta have them to impress the customer with a few heavy-bass riffs. The ratio 14W/50W mids/bass is not that different from a 50 Watt guitar playing with a 200 Watt bass.
Topic: Conn Organ Amp thoughts (Schematic included) (Read 10857 times)