• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

schematics? (also some questions)

m6tt

Member
2007-08-08 12:12 am
Does anyone happen to have schematics for a Hammond organ model 2000 or 3000 (also called an "Everett", or "Everett by Hammond"). Captain foldback does not come to the rescue, nor does google. The amp itself is a Hammond AO-48 (? i think, rusty :) ). EF86, 2x12ax7 12dw7, 2xEL84. It looks like a freakish gibson vox hybrid. The organ was a combination of transistor tone generator and power tube and reverb amp. I just discovered that it had an oscillator in it too today, but it seems as though the oscillator may have simply provided voltage to offboard transistors to create a vibrato. The organ itself expired quite a while ago, and so now it's mounted in an old crate combo (it's not done but looks great so far)...I would really like to know what the deal is with the oscillator section, as well as see as schematic. The oscillator is working, I can hear it if i momentarily connect it to the signal path. I tried doing a bias-tremolo but it didn't work (more reading to do). It's cathode biased, but there was a powersupply for the transistors which provided -12v. Would it make sense to just connect the -12v supply (adjustable) in place of the 130 ohm cathode resistor? Would it make sense to connect the 5-10v oscillator output to the cathode of a preamp tube (no CCSs in the amp...normal cathode biased tubes) to get a tremolo that way?