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turning a hammond tone cabinet into a giant reverb. help!
Old 28th September 2013
  #1
turning a hammond tone cabinet into a giant reverb. help!

So i got the guts of a hammond tone cabinet, i think the pr-40? Can't determine it sadly, but i got ahold of some close schemos and think i see the power plug area. Anybody know these and can help?

My aim is too turn it into a giant stand alone reverb tank. 3 prong power, maybe 1/4th i/o or some xlr if it can be swung.....
Attached Thumbnails
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Old 28th September 2013
  #2
The fist photo is a shot of the top, i think the power cable is coming into the metal housing there, and on the underside of that same plug, i think i can just wire the 3 prong to the red, green and black and disregard the other wires right?


That third photo is a completely ordinary and unrelated caterpillar......
Old 29th September 2013
  #3
Im thinking since the tank will be separate, the rubber shock mounts on the amp can be removed and the entire can bolted to a flat rack panel for shielding and convenience.

Then i have to figure out where the outs are. I imagine they are balanced, as theres three transformers in the amp can......


I think the reverb in plug is my inputs.
Old 2nd October 2013
  #4
Im starting to think this might be from an organ? None of the schemos are matching from the tone cabinets, and what i thought was power in i think isnt anymore.
Old 5th October 2013
  #5
Better photography
Attached Thumbnails
turning a hammond tone cabinet into a giant reverb. help!-cam00299.jpg   turning a hammond tone cabinet into a giant reverb. help!-cam00297.jpg   turning a hammond tone cabinet into a giant reverb. help!-cam00298.jpg  
Old 12th April 2015
  #6
Well, as it turns out, this puppy is a hammond fluid column reverb.

Sadly, info is pretty limited.

Does anybody have one?

I had to repair the spring support mechanism off the driver in the column, and I'm wondering if I should solder the support for the electrical connection, or if I leave it unsoldered for more movement?

And then, to power the amp. Still kinda stumped there.
Old 24th April 2015
  #7
Here for the gear
 

Check out PR-40 schematic here: http://www.captain-foldback.com/Hamm...schematics.htm
Old 26th April 2015
  #8
Lives for gear
 

Well, the connector-ology of Hammond products goes like this:


The 4 pin is balanced in and out (on reverb units, this is balanced in) .
the 3 pin on top of the tank is the output.
the 6 pin sockets are standard leslie power (the unbalanced signal in not used but passed through to the other 6 pin plugs/sockets)
the 5 pin is for amplifiers

(this is not on the reverb unit, but at least you know)
two pin (blade type) is for leslie motors.
Old 1st May 2015
  #9
Well, that confirms some of my suspicions and the schematic.

My big problem is, the 6 pin power input, the 6 pins don't match the schematic, and that's where I need to put power.

If I could figure out which transformer is the power transformer that would help. There's two small ones, im assuming are I/O for the verb. Then, on either end of the can are two more. A smaller black one half embbedded in the can, and another that has two windings wrapped on one core, which I believe is the power, but it's opposite side of where the 6 pins are.

Last edited by sameal; 1st May 2015 at 04:56 AM..
Old 2nd May 2015
  #10
welp, i figured it out.

The HR-1 schem matches the amp can i have, but again, certain elements are not present (tube values are different, no field coil sockets, blah blah), but it's enough to tell where the wiring is. i got the amp to light up the tubes. i still don't know audio I/O, meaning wiring in a patch panel, but today is success enough.

there's plenty of rubber-turned-ceramic wiring to replace in the meantime.


thanks dr.techno, your info was the push that got me here.
Old 2nd May 2015
  #11
Quote:
Originally Posted by freshtapescent View Post
Check out PR-40 schematic here: Hammond schematics here and elsewhere on the Net

now i can see where this amp can is in the schematic, thank you!

this i believe is the schem i should have been looking at. but also, things don't 100% match either.

Last edited by sameal; 3rd May 2015 at 12:42 AM..
Old 3rd May 2015
  #12
Quote:
Originally Posted by drtechno View Post
Well, the connector-ology of Hammond products goes like this:


The 4 pin is balanced in and out (on reverb units, this is balanced in) .
the 3 pin on top of the tank is the output.
the 6 pin sockets are standard leslie power (the unbalanced signal in not used but passed through to the other 6 pin plugs/sockets)
the 5 pin is for amplifiers

(this is not on the reverb unit, but at least you know)
two pin (blade type) is for leslie motors.

given all this, where would i tap an input and out put to run signal through the amp and verb back out to say a console input?
Old 3rd May 2015
  #13
Lives for gear
 

well if we look at this schematic:

http://www.captain-foldback.com/Hamm...JR20_early.gif

you'll notice a 4 pin that is the signal input to balanced line (s2) and balanced reverb return (s3).
Old 3rd May 2015
  #14
Quote:
Originally Posted by drtechno View Post
well if we look at this schematic:

http://www.captain-foldback.com/Hamm...JR20_early.gif

you'll notice a 4 pin that is the signal input to balanced line (s2) and balanced reverb return (s3).


yes, this amp can has both, but that goes to and from the drivers on the fluid verb column. which leads me to believe that there's an input on the same 6 pin connector i supplied power too, and an output on another 6 pin female on this can that isn't on any of the schematics so far. this mysterious six pin receptical is hard wired to a whip with a 6 pin male connector on the other end.

the six pin i supplied power two has two wires on the 6 pin power receptical pins 1&6 that go to pins 1 on the 6j5 tubes. pin one is shell, but there's a resistor i think going to pin 5, grid. I think pins 1&6 on the power input are line input.

then the 6 pin whip, has two wires coming off a transformer at pins 5&6. i think that's the output.


then, phase and ohm are a concern.


all of these schems have different tubes and transformers then my amp can, but the basic layout is close. the tubes in mine are 6j5 and 6j7
Old 3rd May 2015
  #15
Lives for gear
 

Quote:
Originally Posted by sameal View Post
yes, this amp can has both, but that goes to and from the drivers on the fluid verb column. which leads me to believe that there's an input on the same 6 pin connector i supplied power too, and an output on another 6 pin female on this can that isn't on any of the schematics so far. this mysterious six pin receptical is hard wired to a whip with a 6 pin male connector on the other end.

the six pin i supplied power two has two wires on the 6 pin power receptical pins 1&6 that go to pins 1 on the 6j5 tubes. pin one is shell, but there's a resistor i think going to pin 5, grid. I think pins 1&6 on the power input are line input.

then the 6 pin whip, has two wires coming off a transformer at pins 5&6. i think that's the output.


then, phase and ohm are a concern.


all of these schems have different tubes and transformers then my amp can, but the basic layout is close. the tubes in mine are 6j5 and 6j7
this is an interesting combination of sorts. the 6 pin cable should be the one that originally connects to the source where the voltage and input signal should be. then the extension amp is plugged into the 6 pin socket on the chassis.

but all 6 pins are wired like pin 1 bal. line signal - , pin 2 gnd, pin 3 AC power neutral, pin 4 AC power Line, pin 5 is DC B+ (250VDC), pin 6 is bal. line signal +
Old 4th May 2015
  #16
Quote:
Originally Posted by drtechno View Post
this is an interesting combination of sorts. the 6 pin cable should be the one that originally connects to the source where the voltage and input signal should be. then the extension amp is plugged into the 6 pin socket on the chassis.

but all 6 pins are wired like pin 1 bal. line signal - , pin 2 gnd, pin 3 AC power neutral, pin 4 AC power Line, pin 5 is DC B+ (250VDC), pin 6 is bal. line signal +
Well, input should come in on the same 6 pin the power came in.

Output is stumping me. There's a 7 pin socket, the 5 pin additional amps and the 6 pin socket female with the 6 pin male wired to the back of it.

The 6 pin socket female/ male combo has two wires at pins 6 and 5, coming from a small transformer.
I think that may be out put.
Old 4th May 2015
  #17
Lives for gear
 

its still strange pins 6&5, as that would be an unbalanced with power, but I guess. if it is your output, the primary would be hooked up to a pair tubes on the plate or plate cap (depending on output tube) and the center tap would go to power or to a pin 5 of a 6 pin feeding the unit
Old 5th May 2015
  #18
Quote:
Originally Posted by drtechno View Post
its still strange pins 6&5, as that would be an unbalanced with power, but I guess. if it is your output, the primary would be hooked up to a pair tubes on the plate or plate cap (depending on output tube) and the center tap would go to power or to a pin 5 of a 6 pin feeding the unit
unfortunately, that transformer goes from the pin 6 on the power input plug (wired as a ground) and pin 1 of the additional amps 5 pin socket, the other side goes to pin 4 of a mystery 6 pin socket and pin 5 of the additional amps socket.

it can't be my output i feel.

i did wire my input on the power socket, and my out to the 7-pin socket next to it, and i got signal, no verb, and a pretty good buzz.

but both my 6j7 tubes are bad. that could be the buzz. ones leaky and the other is just dead.

this amp can is weird. no schematics match it and it has a 3,4,5, (2) 6 pins and a 7 pin, half of them not wired like the Hammond documents state they are. yet everything in it has the Hammond AO designation and looks stock factory, not homebrew.

if you look at the photo of the amp, the power input plug and the plug i used for output are right by the 4 pin and the 6j5 metal can tubes. the mystery 6 pin socket has the whip coming out of the can next to it which it is wired too, and has a small white mark on the socket. the additional amps is opposite of that.

Last edited by sameal; 5th May 2015 at 12:11 AM..
Old 5th May 2015
  #19
i also received a small shock from the amp turning it on. might want to get rid of crumbling ceramic wiring i presume, or re-evaluate my grounding...
Old 6th May 2015
  #20
Lives for gear
 

I don't know about trying to make something like this work right off the bat (considering it is from an unknown source, who knows what someone did to try to make it a diy project before). I would identify all of the parts, then desolder and remove all of the parts and wires, and start over building it like it needs to be.
Old 7th May 2015
  #21
Im fairly certain it's wired stock.

The work is way too clean.
Old 11th May 2015
  #22
Well, I think my ceramic is dead.

That could be why There's no verb.

Amp can is chrome under all that unfinished metal looking crap. Apparently that's just a whole pant load of tarnish. Weird.

The more I dig into this thing, the crazier it gets.
Old 21st March 2017
  #23
Gear Maniac
 

Did you ever figure this out? Someone just gave me a giant (4') fluid-damped Hammond spring reverb to turn into a standalone unit. My main question is: Does the standard 6SN7 reverb driver play nicely with line level out of your Aux Send or similar?
Old 22nd March 2017
  #24
Nope. It's still on the pile. (It's a big pile!)

I got as far as getting it to make noise, a real ****ty noise, and then i moved a bunch and shelved it.

I think however, it just needs a recap and maybe some resistors.
Old 22nd March 2017
  #25
Gear Maniac
 

Got it. You're using the amp that came with it, I'm gathering. Nothing weird and esoteric.

I mean, more weird than it already is.

Good luck!
Old 22nd March 2017
  #26
Quote:
Originally Posted by slor View Post
Got it. You're using the amp that came with it, I'm gathering. Nothing weird and esoteric.

I mean, more weird than it already is.

Good luck!
Yes, the original amp. I might dig it up now that were talking about it..
Old 23rd March 2017
  #27
The connections to the reverb section from the amp is two black wires. Im guessing unbalanced. The connection out of the crystal pickup is a 3 conductor mic cable.

As far as matching up an amp to the column.....it can be done im sure. But i don't know what it's expecting and putting back out.
Old 23rd March 2017
  #28
The connections to the reverb section from the amp is two black wires. Im guessing unbalanced. The connection out of the crystal pickup is a 3 conductor mic cable.

As far as matching up an amp to the column.....it can be done im sure. But i don't know what it's expecting and putting back out.
Old 5th June 2017
  #29
Gear Maniac
 

Quote:
Originally Posted by sameal View Post
As far as matching up an amp to the column.....it can be done im sure. But i don't know what it's expecting and putting back out.
Wondering if you've made any progress with this. I'm currently stumped on the amp part of the equation. I've drawn a simplified version based on the two (very slightly different) schematics I have.

I've only gotten as far as tacking up the driver stage, and monitoring the tank output through a utility mixer. My notes / questions are:

1. I get a better result / satisfactory drive by increasing V1 grid resistors to 56k instead of 5.6k. One schematic also has .01 coupling capacitors feeding this first stage, but in my quick-and-dirty test I didn't detect a real sonic difference.

2. The transformer I'm using to drive the tank is not center-tapped on the secondary side. I tried grounding one leg, building a fake center-tap with 2 x 100 Ohm resistors, and just floating both legs directly to tank. No real difference either way.

3. I'm curious about the recovery side. Specifically:

-Do I need BOTH V2 and V3? On the "real" amp, V3 is also a mixing stage for the clean signal, and then drier 4 x 6V6 (not drawn here). Given that I'm repurposing a small beater amp chassis, I'd much rather use just 3 tubes total.

-I'm wondering what's the best way to design the output stage. In a "standard" outboard reverb, you're dealing with unbalanced signal, but Hammond used balanced. Does it make more sense to sum the + and - output of the tank? Or keep them balanced and build a push-pull output stage? And if so, does anyone have a recommendation for a suitable push-pull output transformer, I'm thinking 10 - 20 kOhms to 600 Ohms?

Anything else I'm missing? Keep in mind I'm a tinkerer, not a tech!
Attached Thumbnails
turning a hammond tone cabinet into a giant reverb. help!-hammond-reverb-circuit.2.jpg  
Old 5th June 2017
  #30
Well. I got it to turn on and make awful noise. Thats about it. I havent revisted it in awhile, i got a whole load of projects now. My model for sure needs all new caps, and probably resistors.

It sounds like your building an amp for the unit? If so the schematic for the amp can could have some clues. Otherwise im not far enough along in my abilities to answer those questions.
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