It does 😉 !
For the reverb section I chose a rather unusual way: I used a 6DX8, originally designed as video amplifier in b/w TV's. The pentode works on the chassis' original output transformer and drives the Hammond tank. It's driver coil and the cathode are grounded via a small 6 V 30 mA lamp, hence providing NFB and compression simultaneously. The triode is the regeration amplifier.
Best regards!
For the reverb section I chose a rather unusual way: I used a 6DX8, originally designed as video amplifier in b/w TV's. The pentode works on the chassis' original output transformer and drives the Hammond tank. It's driver coil and the cathode are grounded via a small 6 V 30 mA lamp, hence providing NFB and compression simultaneously. The triode is the regeration amplifier.
Best regards!
You kept your Hammond. I had a C3 one time, which I disposed of to a guy that drives around the US in a moving truck full of 'em; said he has them fixed and then sells to Euro customers. When I look at my life from then to now, the C3 never would have made it, so it was the right decision.
Well, that AO-64/68 was part of a Hammond K-100 organ. Those organs sound really, really bad without any trace of what we know as the hammond sound, hence are pretty useless and worthless. Till today I collected three of them just for the tube amplifiers and the speakers, which are fine for guitar. I plan to convert both remaining amps into monoblocks , using the OPT's CT'ed speaker winding for cathode feedback.
The organ I still own is a '50 or '51 C-2 in a beautiful quatrefoil enclosure:
Best regards!
The organ I still own is a '50 or '51 C-2 in a beautiful quatrefoil enclosure:
Best regards!
Yes, thank you 😉 ! And that's exactly why I bought this first owner C-2. I know that a C-3 is the 'better' organ, but only very early C-3's came in this nice decorative cabinet. And these are hard to find. Anyway,in the meantime I've installed a percussion unit by Trek II that does more than the Hammond Harmonic Percussion in B-3's, C-3's etc.
Best regards!
Best regards!
FEATURES:
• Three harmonics... second, third and fifth
• Individual level control for each harmonic
• Adjustable decay rate
One of my favorite sounds in jazz! Must be fantastic!
• Three harmonics... second, third and fifth
• Individual level control for each harmonic
• Adjustable decay rate
One of my favorite sounds in jazz! Must be fantastic!
Yesss, exactly! The Trek II TP-2B percussion unit may sound exactly like the original Hammond 2nd and 3rd percussion, but offers much more to enhance the organ' sounds.
In it's original estate the 8th drawbar would have been permanently disabled. So I added a dual throw sliding switch and an aditional wire to have it enabled or disabled deliberately. Sadly I had to discard my original intents to add a 10th contact row to the swell manual, due to it's limited space.
As I shot my TP-2B about two decades ago via ebay from the U.S. and had it laying in my shelves since, I just had to replace the 115 Vac power transformer by a suitable 230 Vac one. That's it.
Best regards!
In it's original estate the 8th drawbar would have been permanently disabled. So I added a dual throw sliding switch and an aditional wire to have it enabled or disabled deliberately. Sadly I had to discard my original intents to add a 10th contact row to the swell manual, due to it's limited space.
As I shot my TP-2B about two decades ago via ebay from the U.S. and had it laying in my shelves since, I just had to replace the 115 Vac power transformer by a suitable 230 Vac one. That's it.
Best regards!
How does it connect (I wonder)? Seems like just a box with a few wires; I assume whenever you press a key on a hammond, you get 2nd, 3rd and 5th all simultaneously on 3 individual buses that the drawbars hook into, that this thing then connects into, envelopes and mixes, sending its output back into the organ' amp.
How does the organ tune at 50Hz line? Special motor for Europe? I always liked the "glissando" trick some players would do by turning the motor off while playing; however I've never heard anyone hook up the motor to an oscillator / power amp to do that effect - and keep on playing at a lower / higher key - instead of, say, just crashing the pitch at the end of a song. It could be done, just surprised nobody's thought of it - AFAIK - and incorporated the effect into a performance.
The 2nd, 3rd and 5th harmonics' wires need to be disconnected from the drawbars and wired into the unit where they are amplified by an opamp each. Their ouput signals are fed back into the organ and also to the three sliding potentiometers in the unit, where they are mixed and amplifed via an OTA (now obsolete CA3080), which is triggered by the 8th harmonic's wire.
An European 234 Vac 50 Hz TWG features another motor (four pole stator, four pole armature), spinning at 1500 rpm. The US 117 Vac 60 Hz motor is four pole stator/six pole armature and spins at 1200 rpm. Both motors are of the reluctance type. Hence, all twelve gear ratios are different also in European TWG's to have the same pitch (a' = 440 Hz).
Best regards!
An European 234 Vac 50 Hz TWG features another motor (four pole stator, four pole armature), spinning at 1500 rpm. The US 117 Vac 60 Hz motor is four pole stator/six pole armature and spins at 1200 rpm. Both motors are of the reluctance type. Hence, all twelve gear ratios are different also in European TWG's to have the same pitch (a' = 440 Hz).
Best regards!
I used to use that for VCAs and VCFs, back when. Sounds like you "could" have a whole analog synth patch on each of those harmonic lines, beyond just a VCA. But then it wouldnt be a famous Hammond sound anymore, it'd be something else...
Better not get George thinkin'; he'll build it and hook it to his M100 ;') As long as it's reversible.
Rochester made a few wafers. 10,000+ in the bin. Hobbyists can buy a few here:
https://smallbear-electronics.mybigcommerce.com/ic-ca3080ae/ (I know SB sold-out to another shop?).
DigiKey also lists the Rochester part, but you have to make the $250 minimum order from Rochester.
Yes, eBay is full of "CA3080" but I have not had a report of a WORKING 3080 from there in a decade or two. (Guitar pedals love the thing, and life has been disappointing, even MusicDing was shipping duds a few year ago.)
Yes, I was wondering how Trek II still keeps offering this unit despite it's obsolete chip 😉 .
Best regards!
I think it is possible to hook it into a M-100 also with some tweaks. Anyway, this organ features stock percussion, it's amplifier is not very different from an (B-3's etc.) AO-28 with this respect. Also anyway, as far as I know George's (if we're speaking about Tubelab) organ is a M-3, no? This organ features exactly the same harmonic percussion we know from B-3's, C-3's, A-100's etc. Even the four switch assembly is interchangeable.
Best regards!
I had one of those (M3) also, in times past. You clearly know a lot more about Hammonds than I do.
When I was in high school, I had to good fortune to hang out with a fellow who was a Hammond tech by day, synth module builder and sound sculptor by night. I'd get to do things like borrow his rackmount ring modulator he designed, using just 741s - or play with his ARP 2600 for an afternoon. That would be circa 1975.
It's always great to get to hang out with folks who are more knowledgeable than you, whether playing music or doing electronics.
Exactly. Anyway, I have to admit to be more the electronics guy than the musician, despite playing several instruments 😉 . After all, I'm just a hobbyist with a - very - different profession.
Best regards!
Best regards!
I have some original NOS CA3080 in my stash, if somebody needs them e-mail me.
I’m so sorry I missed this when you posted it.
The resistor value is 2W 2.7K @ 10% (red/purple/red/silver). It’s probably a bit late for this information now, but since it’s not visible in my original photos I figured I’d add it just in case.
I’m just now finally getting around to restoring this amp, and after recapping (aside from the large cans) it eventually warmed up and sounds really clean on the 1/4” input. Now that it passed initial testing (after it was brought up to voltage on a variac over several hours) it’s time to draw out the schematic so I can figure out where I want to mod it.
It seems to have a separate gain stage for both the phono input and the 1/4” input, so chaining those together will probably be my first modification. Once I get a cabinet built to hold a decent sized speaker. Currently I’ve been testing with a 4” surround speaker.
I already have the new speaker, a Jensen Blackbird 12”.
It’s amazing how much more room is in the chassis without those Tropicaps.
Attachments
Finally a schematic!
I spent the past couple of days figuring out how to draw a schematic of this amp, and through brute force I managed to cobble something together. Uncle Doug’s tube basics helped a ton, and once I knew what each component was doing I knew what to look for as I was tracing through the circuit.
That being said, this is my first schematic, so I’m not sure what the conventions are. I know my power rail doesn’t look like what I see in most schematics, but I think it still makes sense.
It’s not totally complete, since I haven’t measured any voltages yet and most of the potentiometer values are a mystery still since I’d have to disconnect them to get something accurate. I’ll add those once I start rebuilding the preamp stage, though they’ll likely change during the modifications so they’re not super important at the moment except for completeness. I also cannot yet identify the diodes in the rectifier. Power transformer still remains to be specced out too. Coming soon!
I drew this in Inkscape and created my own symbols, so hopefully those are conforming to standard.
One thing I noticed when tracing this out is that I was under the impression that the last 12AX7 before the power tubes was a dedicated phase inverter, but it appears that only half of the tube is. If anybody has any insight into how the amp and/or tubes are configured here I’d appreciate it, since I’m still mostly clueless when it comes to tube configurations and design choices.
I definitely understand way more about how this amp is built now that I traced through the circuit though. Twice, actually. On my first attempt at a schematic I got the cathode and plate pins mixed up when I drew the tube symbols, and I didn’t realize it until I started tracing through my finished schematic and nothing made sense. I couldn’t figure out why every tube before the power tubes was feeding the audio signal out the cathode.
Lesson learned, lol.
I spent the past couple of days figuring out how to draw a schematic of this amp, and through brute force I managed to cobble something together. Uncle Doug’s tube basics helped a ton, and once I knew what each component was doing I knew what to look for as I was tracing through the circuit.
That being said, this is my first schematic, so I’m not sure what the conventions are. I know my power rail doesn’t look like what I see in most schematics, but I think it still makes sense.
It’s not totally complete, since I haven’t measured any voltages yet and most of the potentiometer values are a mystery still since I’d have to disconnect them to get something accurate. I’ll add those once I start rebuilding the preamp stage, though they’ll likely change during the modifications so they’re not super important at the moment except for completeness. I also cannot yet identify the diodes in the rectifier. Power transformer still remains to be specced out too. Coming soon!
I drew this in Inkscape and created my own symbols, so hopefully those are conforming to standard.
One thing I noticed when tracing this out is that I was under the impression that the last 12AX7 before the power tubes was a dedicated phase inverter, but it appears that only half of the tube is. If anybody has any insight into how the amp and/or tubes are configured here I’d appreciate it, since I’m still mostly clueless when it comes to tube configurations and design choices.
I definitely understand way more about how this amp is built now that I traced through the circuit though. Twice, actually. On my first attempt at a schematic I got the cathode and plate pins mixed up when I drew the tube symbols, and I didn’t realize it until I started tracing through my finished schematic and nothing made sense. I couldn’t figure out why every tube before the power tubes was feeding the audio signal out the cathode.
Lesson learned, lol.