So, today I picked up this wurlitzer organ at an auction.
Open her up and start looking for useable tubes.
28 pcs 12FQ8's RCA Date coded 63-17 all test great on my P.O.S national professional tester.
Are these good for anything other than where I got them?
Twin Double Plate Triode's
Really pretty looking tubes anyways, Labeled wurlitzer Made by RCA In usa Shiney black plates. Orange labeled.
Gene
Open her up and start looking for useable tubes.
28 pcs 12FQ8's RCA Date coded 63-17 all test great on my P.O.S national professional tester.
Are these good for anything other than where I got them?
Twin Double Plate Triode's
Really pretty looking tubes anyways, Labeled wurlitzer Made by RCA In usa Shiney black plates. Orange labeled.
Gene
Hmm FQ8? FQ7 would be a 12V 6CG7, but 8...hmm I'm guessing something like 12DT8 maybe, but a taller envelope?
Lesse...
http://www.mif.pg.gda.pl/homepages/frank/sheets/093/1/12FQ8.pdf
Hmm, whoa, one cathode, two grids, four plates? Wild stuff!
12AX7-ish gain, but a 12AT7 curve. Not terribly linear, not much current, but good gain. Could use it in a phono I suppose.
Would be good for splitting a signal in two with no crosstalk. Take one triode and use two individual plate loads, coupling to whatever circuits as needed. One can't effect the other. Well, in theory that is. I wonder how the plates interact?
- Any idea what it was used for in inside the organ? Oscillator perhaps? The extra plate would allow tapping a Hartley osc. without pulling it too bad...
...28 pieces? Probably main oscillators then. Maybe four harmonics (=octaves) in one tube? Flip-flop dividers, or does each plate have an LC tank?
Oh, and if you say something looks nice... you MUST supply pics.
Tim
Lesse...
http://www.mif.pg.gda.pl/homepages/frank/sheets/093/1/12FQ8.pdf
Hmm, whoa, one cathode, two grids, four plates? Wild stuff!
12AX7-ish gain, but a 12AT7 curve. Not terribly linear, not much current, but good gain. Could use it in a phono I suppose.
Would be good for splitting a signal in two with no crosstalk. Take one triode and use two individual plate loads, coupling to whatever circuits as needed. One can't effect the other. Well, in theory that is. I wonder how the plates interact?
- Any idea what it was used for in inside the organ? Oscillator perhaps? The extra plate would allow tapping a Hartley osc. without pulling it too bad...
...28 pieces? Probably main oscillators then. Maybe four harmonics (=octaves) in one tube? Flip-flop dividers, or does each plate have an LC tank?
Oh, and if you say something looks nice... you MUST supply pics.
Tim
Sch3mat1c said:Hmm FQ8? FQ7 would be a 12V 6CG7, but 8...hmm I'm guessing something like 12DT8 maybe, but a taller envelope?
Lesse...
http://www.mif.pg.gda.pl/homepages/frank/sheets/093/1/12FQ8.pdf
Hmm, whoa, one cathode, two grids, four plates? Wild stuff!
12AX7-ish gain, but a 12AT7 curve. Not terribly linear, not much current, but good gain. Could use it in a phono I suppose.
Would be good for splitting a signal in two with no crosstalk. Take one triode and use two individual plate loads, coupling to whatever circuits as needed. One can't effect the other. Well, in theory that is. I wonder how the plates interact?
- Any idea what it was used for in inside the organ? Oscillator perhaps? The extra plate would allow tapping a Hartley osc. without pulling it too bad...
...28 pieces? Probably main oscillators then. Maybe four harmonics (=octaves) in one tube? Flip-flop dividers, or does each plate have an LC tank?
Oh, and if you say something looks nice... you MUST supply pics.
Tim
OOOps,
Yep,, I beleive ocilli's, They were divided up into 3 banks/chassis all labeled.
This thing had a really weird compliment of tubes, 9 GE 12ax7s, 3 6EU7's, 1-6U4, 1 - 6AU6 and a couple 7868's on output.
2- 12 inch instrument speakers, and some kinda mechanical leslie thingy with 2 about 5 inch speakers, reverb tank,, and a humdity control heater??
HUGE power tranny!!!! must be 15 lbs of iron lol
Gene
Heres a Pic of the tube, Sorry bout my poor camera skills, We just bought this new cannon and havent mastered it yet lol
Height and diameter of the tube is the same size as a 12AX7. internally of course is very different.
Height and diameter of the tube is the same size as a 12AX7. internally of course is very different.
An externally hosted image should be here but it was not working when we last tested it.
Resurecting the thread - any more input?
I found a Wurlitzer organ with these tubes too. (possibly the same model?)
someone had already stolen the 12AX7's at the thrift store before I got it but I only paid $1.
Because it was missing so many parts, and in pretty bad shape, I parted it out right there behind the store in about an hour.
Saved what tubes were left (mostly 12FQ8, some 6EU7), what sockets I could, as well as many of the switches, speakers, vibrato unit, spring reverb unit, and swell pedal.
Has anyone got any schematics that use the 12FQ8 tubes? Is a wah possible with these tubes? I don't have much experience building things with tubes yet.
I found a Wurlitzer organ with these tubes too. (possibly the same model?)
someone had already stolen the 12AX7's at the thrift store before I got it
but I only paid $1.Because it was missing so many parts, and in pretty bad shape, I parted it out right there behind the store in about an hour.
Saved what tubes were left (mostly 12FQ8, some 6EU7), what sockets I could, as well as many of the switches, speakers, vibrato unit, spring reverb unit, and swell pedal.
Has anyone got any schematics that use the 12FQ8 tubes? Is a wah possible with these tubes? I don't have much experience building things with tubes yet.
The 12FQ8's are probably the frequency dividers. Some of them may be used as oscillators as well. Look for a pot or trimmer cap that is used to tune the upper octave (12 notes) of the organ. These will be connected to the oscillators. Each oscillator's frequency is divided by two to generate the next lower octave, and divided again for the next octave. Each twin plate triode can generate two different divide ratios when used as a triggered relaxation oscillator. The time constant is set up to be just a little longer than the desired repitition rate and a trigger pulse is applied to the grid. It is possible to build a multivibrator that runs at two frequencies at once (related by a factor of two) using one of these tubes.
Way back in the late 60's I had a Baldwin organ that used 36 6SN7's in the tone generator circuit. 12 were oscillators and 24 were frequency dividers. It had a huge power transformer, but most of the size was because of the huge filament requirements to light all of the tubes. I eventually sold it, but figured out how it worked, and built my own version using RTL IC chips from scrap PC boards (in 1970). The organ no longer exists, but I still have those hand wired boards.
Way back in the late 60's I had a Baldwin organ that used 36 6SN7's in the tone generator circuit. 12 were oscillators and 24 were frequency dividers. It had a huge power transformer, but most of the size was because of the huge filament requirements to light all of the tubes. I eventually sold it, but figured out how it worked, and built my own version using RTL IC chips from scrap PC boards (in 1970). The organ no longer exists, but I still have those hand wired boards.
Go to your local library and try to locate a book called The Electronic Musical Instrument Manual. The earlier the version the better because once you hit the early 70s copyright a lot of tube stuff was removed. Its a must have for anyone who wants to make noise with tubes.
If anyone has the opportunity to acquire a Novachord don't pass it up! Listen to the samples near the bottom of the page
http://www.discretesynthesizers.com/nova/intro.htm
If anyone has the opportunity to acquire a Novachord don't pass it up! Listen to the samples near the bottom of the page
http://www.discretesynthesizers.com/nova/intro.htm
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