Anybody recognize this?

[drhulsey]

I bought this small amp along with a Type IV Hammond reverb tank.
3F23 on top, 8692936 stamped on top, no markings inside.
One transformer- 95-1791, 138033 stamped on bell
Tubes, 6X4, 6BH8, 12AU7
One cap can- 40/20/20

I have Googled everything I can think of and checked captainfoldback and don't find anything close.

[skyboltone]

....bad post....mis-read info. Will think again in a minute. Well, if it's a reverb driver you would expect a little bitty transformer under the chassis. Maybe they are using a cathode follower for the driver stage on the tank? If it doesn't have an AO-xx number stamped on the chassis it's unlikely it's a Hammond chassis. The tank just got collected at the same time? Are there matching connectors between chassis and tank?

I think what cha got there is a PT that may work for some variation of a Dumbleator.

[drhulsey]

No transformer under the chassis. Also, no bulbs to dissipate the input like a speaker driven reverb amp. There is a faint number stamped on the chassis: 100311. It has RCA connectors on two cables that fit the tank. One is a single conductor that has been marked as the output to the tank. The chassis must have to be grounded together.
The tank coils seem to be good. They register 165R each. Accutronics has a chart that gives you the DC resistance for different tanks, but this one is pre-Accutronics.
I'm trying to lay out a schematic. It sure is a bitch to untangle that point-to-point mess
What I really want to do is come up with a speaker driven reverb unit like the Mojoverb. I'm still looking for an old Hammond reverb amp. They were speaker driven.

[skyboltone]

No transformer under the chassis. Also, no bulbs to dissipate the input like a speaker driven reverb amp. There is a faint number stamped on the chassis: 100311. It has RCA connectors on two cables that fit the tank. One is a single conductor that has been marked as the output to the tank. The chassis must have to be grounded together.
The tank coils seem to be good. They register 165R each. Accutronics has a chart that gives you the DC resistance for different tanks, but this one is pre-Accutronics.
I'm trying to lay out a schematic. It sure is a bitch to untangle that point-to-point mess
What I really want to do is come up with a speaker driven reverb unit like the Mojoverb. I'm still looking for an old Hammond reverb amp. They were speaker driven.

I believe that the famous AO-35 was a reverb driver. It has a regular 8 ohm ouput transformer though. There is another one with a pair of 6BM8s that I believe is a reverb driver. Also with transfomer. Where is the mojoverb scheme?

[drhulsey]

... Where is the mojoverb scheme?

Only the folks at Mojo Musical know that:
http://www.mojomusicalsupply.com/item.a ... d=MOJOVERB

[CaseyJones]

No transformer under the chassis. Also, no bulbs to dissipate the input like a speaker driven reverb amp. There is a faint number stamped on the chassis: 100311. It has RCA connectors on two cables that fit the tank. One is a single conductor that has been marked as the output to the tank. The chassis must have to be grounded together.
The tank coils seem to be good. They register 165R each. Accutronics has a chart that gives you the DC resistance for different tanks, but this one is pre-Accutronics.
I'm trying to lay out a schematic. It sure is a bitch to untangle that point-to-point mess
What I really want to do is come up with a speaker driven reverb unit like the Mojoverb. I'm still looking for an old Hammond reverb amp. They were speaker driven.

I believe that the famous AO-35 was a reverb driver. It has a regular 8 ohm ouput transformer though. There is another one with a pair of 6BM8s that I believe is a reverb driver. Also with transfomer. Where is the mojoverb scheme?

Doctor, doctor... gimme the news... I got a bad case of (some kind of funky Asian flu... can't make it rhyme... )

The mainstream Hammond reverb amps are the AO-35 and the AO-44. The one to get is the AO-35, make sure it's intact and don't be a pervert and convert it into a Carmen Ghia or something! What a perfectly stupid waste of a good reverb amp...

I used to be able to buy them for under $20 each "all day and all night", then someone found out there were good parts in there...

Make sure the bulbs in the limiting circuit on the front end are intact, more bulbs = more limiting. There's usually one bulb on the front end although there are sockets for two. It's supposed to be used with a 2x6V6 amp capable of a raging 12 watts, you might want to pad it down with an attenuator (yeah, right. Attenuator + attenuator = more attenuators!) if you're using a larger amp, say anything bigger than a Deluxe Reverb. Which has reverb already come to think of it...

The AO-35 was supplanted by the AO-44, that's the unit with the two ECL86/6GW8s. It's actually a simpler unit in many ways, there's one transistor (yuck!) in there and a solid state rectifier. I still have a soft spot for the AO-35, after all you can make an amp out of it...

Golly, gee whiz... I can buy half a dozen AO-35s for what one Mojoverb sells for.

Your little amp... not Hammond. Check out the tidy tagboard layout of Hammond stuff. The only thing semi-chaotic they did was the old chord organ and even that flies between neat rows of terminal strips.

[drhulsey]

... Your little amp... not Hammond..

That's OK. It'll give me an exercise to draw out a schematic from the layout.
I've bought an AO44 and am looking for an AO35. I really want to use it for a speaker-driven reverb. It would be nice to add dwell and reverb controls. Some EQ'ing would be nice, too.
That's not asking too much, is it
Casey, do you know what the impedances were on the old Gibbs units (the 17" 4-spring, not the necklace or the oil-filled tower)? Those units were fed by the 8 ohm OT output, so I ass-u-me (I beat you to it) that would mean the tank should have an 8 ohm input impedance. The input resistance on the amps is high(10k, 47k respectively). Some Accutronics units have 10k and 12k output impedances. Is that what the amp wants to see?
One electronics idea I haven't quite got my head around is, "What kind of resistance/impedance/load a particular portion of a circuit is 'looking for' in the section to follow?" For optimum performance, I presume?
The 8 ohm OT/8 ohm speaker I get. But what about what one amplifier stage looks for in the next?
Pardon my ignorance

[CaseyJones]

... Your little amp... not Hammond..

That's OK. It'll give me an exercise to draw out a schematic from the layout.
I've bought an AO44 and am looking for an AO35. I really want to use it for a speaker-driven reverb. It would be nice to add dwell and reverb controls. Some EQ'ing would be nice, too.
That's not asking too much, is it
Casey, do you know what the impedances were on the old Gibbs units (the 17" 4-spring, not the necklace or the oil-filled tower)? Those units were fed by the 8 ohm OT output, so I ass-u-me (I beat you to it) that would mean the tank should have an 8 ohm input impedance. The input resistance on the amps is high(10k, 47k respectively). Some Accutronics units have 10k and 12k output impedances. Is that what the amp wants to see?
One electronics idea I haven't quite got my head around is, "What kind of resistance/impedance/load a particular portion of a circuit is 'looking for' in the section to follow?" For optimum performance, I presume?
The 8 ohm OT/8 ohm speaker I get. But what about what one amplifier stage looks for in the next?
Pardon my ignorance

Geez, I've been off bullshitting and I missed this one.

Old Hammond / Gibbs reverb units: They're like old Rambler automobiles, I swear Gibbs never made two units alike. That means it's a good idea to buy the tank that goes with your reverb amp, otherwise the chances of getting the right tank on eBay are slim. I'm not being my usual wise-ass self here, I'm serious. There probably isn't a wide range of transducers but when you start mixin' 'em up there's a mind boggling range of combinations available. Gibbs even engineered intended mounting orientation into the units.

You got the 8 ohms in part. Be aware that there are a couple other versions that aren't transformer driven like 150 ohms on the first transducer for instance. If you get one of those it won't do squat with your AO-44. Not speaker driven, anyway.

Lucky for you the commonly available Accutronics pan intended for replacement use in '60s Fender amps works fine with the AO-44. Don't mess with the Ampeg replacement tank.

If you can find a necklace try that. It's supposed to be sweeter than a 17" tank. The trick is to find one that hasn't done an old slinky impersonation, necklaces with crappy springs are common and clean ones are rare.

Tall oil filled units make great spare parts for other tall oil filled units. Someone out there somewhere probably thinks the oil filled units are the last word in tone. I got some nice dried out Jensen field coils to go with that guy's oil-filleds.

[Buschman]

My a0-35 became an 18 watt lite IIb. I would do it again in a heartbeat. It is one of my main gig amps(moneymaker).

[drhulsey]

... I'm not being my usual wise-ass self here, I'm serious...

Aw, come on, Casey. You're tryin' to fake me out

If you can find a necklace try that...

The damn necklaces take up a s***tload of space
I really just want to try to fix up a nice speaker-driven reverb driving its own speaker. That gets the reverb past the power amp section, which is the best place for it. It'll be a good project to keep me out of trouble for a while.
I'm sure it will generate some recognition of ignorance on my part that will require questions for those of you more electronically enlightened
Kinda like Andy fabricating a custom reverb tank from delicate spare parts just for the challenge of it, except he really knows what he's doin'

[CaseyJones]

The damn necklaces take up a s***tload of space )

The damn 17" tanks take up a shitload of space! They take up a shitload of space because they need to be 12" away from any power transformer or they hummmmm... Well, they don't hum all by themselves. They make a handy antenna to pick up any available hum which they pass on to the high gain recovery stage...

I really just want to try to fix up a nice speaker-driven reverb driving its own speaker. That gets the reverb past the power amp section, which is the best place for it. It'll be a good project to keep me out of trouble for a while.

AO-44 plus replacement Fender tank, stuff it in a box and connect it to a speaker. Done. I can put it together outta crap I have on hand in the next 20 minutes. Not braggin', I'm just lucky I guess.

We shouldn't be talkin' about this. I'll never get a cheap AO-44 again!

I'm sure it will generate some recognition of ignorance on my part that will require questions for those of you more electronically enlightened
Kinda like Andy fabricating a custom reverb tank from delicate spare parts just for the challenge of it, except he really knows what he's doin'

Well I can put together electronics but I can't do my own sutures.

Do I get partial credit for self-medicating?

[dartanion]

That's part of an old Zenith Console Phonograph. I'd recognize those ink stamps and stick on labels anywhere as I have parted out a few of these old beasts.

[drhulsey]

... AO-44 plus replacement Fender tank, stuff it in a box and connect it to a speaker. Done...

That's my goal.

... I can't do my own sutures.

I actually had to sew myself up once. I accidentally stabbed myself in the belly with a scalpel IT"S ONLY A FLESH WOUND Once it's numb, it's just like sewing up someone else It could have been a problem, though, if I had sat on it

... Do I get partial credit for self-medicating?

I know nothink I see nothink I hear nothink

That's part of an old Zenith Console Phonograph.

Thanks I just knew that of all the eyes on this forum, someone would recognize it.

[CaseyJones]

... I can't do my own sutures.

I actually had to sew myself up once. I accidentally stabbed myself in the belly with a scalpel IT"S ONLY A FLESH WOUND Once it's numb, it's just like sewing up someone else It could have been a problem, though, if I had sat on it

"THERE GOES YER STREET CRED"

Ah, but the patient was probably under general anasthesia so they didn't notice. I betcha it got your attention, though.

"I see nothink!!"

The intern on duty stabbed himself with a needle last time I was in the emergency room with a big ol' gory wound. Lotsa extra paperwork every time that happens...

That's part of an old Zenith Console Phonograph.

Thanks I just knew that of all the eyes on this forum, someone would recognize it.

Well... damn! Don't I feel like a dumb-ass! I had one of those Zenith consoles, I grabbed it because it had reverb. That was years ago but I generally remember things like that....

[skyboltone]

I know nothink I see nothink I hear nothink

Good old Shultz. What a great character.