Can someone tell me what this is?

[silat]

I got this the other day from an antique store really because of the tubes 2- 5Y3 rectifiers, 4 -6V6's and 1- 7025/12AX7 for 40 dollars. All strong and good by the way. I was wondering what your  thoughts were and what I should build from it? I have no idea what it is and maybe somebody can tell me? I am thinking an organ amplifier?

[silat]

I thought people would jump right on this.....

[pompeiisneaks]

I don't know, but sometimes it can take a few hours for people to respond.  Is there nothing on the chassis that indicates what it is?  As far as what to build from it, you know the transformers are capable of handling 2 rectifiers and 4 6v6's so you could likely convert to a push/pull 2x6v6 amp with a few preamp tubes and still sit well within the range of the existing transformers.   Since it only has power tubes and rectification this likely is a power amp only.  Maybe a PA amp?  Could also be an organ amp.  A fender 5e3 Deluxe has two 6v6, a 12AY7 and a 12AX7 with a 5y3GT rectifier.  Sounds like a perfect fit if that sounds good to you?

~Phil

[eleventeen]

Looks great, good score!


Most likely an organ amp, or could be an amp from a stereo console. No controls? Check. Several chassis plugs (usually 6 or 7 pin) that "remote" the on-off switch? Check. No real preamp, only a single 12AX7 probably divided into two identical phase splitters? Check...OR...a single stage preamp (1/2 the 12AX7) and a phase splitter/inverter and the output is mono and the power output section is 4 qty 6V6.


Looks like a CONN.


Very nice score. You could make a guitar amp from it...a 5E3 Deluxe driving 4 qty 6V6 with maybe 2 of them switchable-off would require very few parts and make a pretty interesting amp, I think. 


Before starting to drill/hack, strongly suggest you stare at it for a while and make sketches, plot, and plan.


The issues are always:
metalwork on a steel chassis
room for a parts board if you choose to build using one
room for pots for tone controls & vol.
awkward shape of chassis.

[silat]

Thank you both for your  great replies. I was looking around the inter-webs and found that it looks like a Conn organ amp. So your reply is making think that. There is nothing on it to indicate what it is.there is no on/off switch or controls.

[kagliostro]

Nice Score 

Franco

[Paul1453]

A 2nd picture of its guts also helps.

A very nice parts score for $40, for sure.

It definitely meets my buying criteria of 50% of new parts cost delivered.

Depending on the OT, you have the majority of the parts for a 6V6 Plexi there.

If it is a stereo output with 2 OTs, that's even better.  Then 2 Plexis could be made.

Otherwise, a quad 6V6 Plexi is reasonable, and exactly what I am building now.

There is a chance your amp used a field coil speaker, which can render the OT difficult to use.
Unless you get field coil speakers.

But if all you need to buy is an OT to make a real guitar amp, you'll probably be able to build one from that for less than $200 total.

[silat]

Here is the gut shot.

[silat]

Paul do you have a picture or layout or anything on the Plexi you are building? That sounds interesting.

[Paul1453]

It is the Hoffman 6V6 plan.
Full build plans posted on this site.

I modified it a little to run a lower voltage B+.
It sounds great!

Looks like you have a choke in there too.

The OT looks like it is for all 4 of the 6V6s.

That may not work for the Plexi if yours used a field coil speaker like mine did.
But it should work for something else.
Calculate the Z for the OT and you'll know what it is good for.

For my quad 6V6 Plexi I used a PP 6L6 OT I had in my junk pile.
It will give me a 4.7K plate load with 8 ohm speakers, close enough to the 4K it wants for me.
The OT mine had would have given me over 12K @ 8 ohms, no good.

[eleventeen]

It's mono. (single input jack) The transformer thing underneath the chassis is a choke, located as it is between the two e-cap cans. Having bought only the chassis, now you don't have to take apart the whole rest of the organ and haul it away. Yes, you would get a ton more parts from same if it was a CONN but the tubes would all be 12AU7 = low value. So that's a good thing, IMO.


Thought process (for me): If you use that chassis, it isn't shaped that conveniently for a head, eg; not a long narrow chassis.


Move the ecaps & choke to in between the trannies. You don't (and I wouldn't) have to reuse those ecaps. Make a small parts board (or two chassis-mounted terminal strips facing each other) and mount new ecaps on same, in between the trannies. That means you don't have to make big chassis holes for those cap cans.


Now, do you have enough room between where the row of tubes is and the "front" (the wall of the chassis that the choke is currently mounted on) for a few preamp tubes AND pots AND a parts board (should you wish to build using one) ?


Almost. Close call! In many chassis of this type, you flat out do NOT have enough room to do so without really piling the parts on top of each other. Probably no room for a parts board but you could go point to point. Remember...need room for the controls!


But the big decision is whether you reuse that chassis in the first place. That's kind of the big deal, the main decision, IMO. What would be great would be to find a dead solid state amp for $20, strip it out, and build your project in same. You have the perfect pile of parts for such an exercise. Now you have a cabinet with Tolex covering, a handle, corners, and it's a rugged package you can haul around instead of a science fair project. 

[Paul1453]

eleventeen has far more experience with these conversions.

He is one of my junk gear hero's.   

He has given you excellent advice.
The choice of trying to use that chassis or not, is key.
It is a lot more work to use it.
You'll have to cut new holes, fill in others etc.
But bottom line is, you bought quite a few vintage parts to use at a very good price. 

[kagliostro]

I think there is enough space for one of this beauties

http://sluckeyamps.com/dual_lite/dual_lite.htm  --  http://sluckeyamps.com/dual_lite/dual_lite.pdf

http://sluckeyamps.com/6v6plexi/6v6plexi.htm --  http://sluckeyamps.com/6v6plexi/6v6plexi.pdf

Franco

[eleventeen]

Just as a random suggestion, I believe a really cool amp would be a Princeton Reverb that could drive either 2x or 4x 6V6 outputs. Could build that on a Deluxe chassis. normal DR = 6 little tubes, 3 octals. Change to 5 octals, 4 littles. Kewl. If you didn't care about tremolo, you could lose the trem tube and throw a very simple extra gain stage in there. That would be a monster config if you could get it working.


There are about 5 ways you could go on this project. But the big big choice is the chassis and box. A dead Peavey bandit would be ideal. The great thing is how patiently it will wait for you to figure it all out!

[silat]

Yeah that does sound cool too. I am more than likely going to go with what does not cost me much.

[Paul1453]

If you have more time than money, that chassis could be used.

I have re-used a few organ chassis, because I also don't have a ton of money.
But it takes lots of time to visualize your layout and work out the wiring and other issues.
Most of the time you will need to do point to point wiring because the standard board doesn't fit or work well with your layout.
I kind of like the challenge, when I'm successful.

[silat]

That may be the way to go with this one. Or maybe a split chassis would maybe work . I have never done one and I am afraid I will mess it all up.I have still got a Baldwin organ amplifier with two rectifiers and four 6l6's... I have never done anything with it. I got it for 25.00 dollars.I am going slow on a BF twin reverb deluxe  to use on that baldwin model but I am afraid of the split chassis it seems beyond my skill level. I have built plenty: 3 tweed deluxes, a tweed princeton, a 59 bassman and a host of others. But the organ amplifiers I have never been able to just take off on them. I do not feel like I have the know how yet. This forum has been a great help to me and I appreciate everyone here and what they have done.

[sluckey]

The amp is a ppp 6v6 power amp, probably 25 to 35 watts, looks to be cathode biased. I would make it work just as it is, IOW, fix anything that may need fixing. Then you can add a single tube guitar preamp (plenty to choose from) to get it guitar friendly. One more tube would not be hard to put on that chassis, especially if you move the choke and filter caps back between the transformers.

[eleventeen]

The split chassis is not a bad way to go at all and IMO is actually constructive, if that's the right word.


First, the whole preamp would be (I assume) enclosed in a metal box and you give it B+, ground, and heater volts. So it's fully shielded, guitar in and ~~ 1 volt out, something like that. Fairly noise-resistant. If you make it pretty generic, then you can lash it up to this kind of nameless/faceless organ amp. Inside the preamp box, you make some sort of provision so that it can run from high B+ or low B+. That's nothing more complicated than a few-watt resistor you can short out, or not, as need be.


Now physically mounting it in a movable cabinet is not very easy, but you already have a klutzy situation with that fat (and sort of square) organ chassis you are showing here. All it is is a 2-tube or 3-tube project that's pretty simple since it requires no power supply.


The fact of the matter is that if you had such a thing and could lash it up to this Conn chassis, it would give you the confidence to proceed to build an all-in-one amp on one chassis...and of course, you would have to obey the gen'l principles of low noise, low hum, but these are known.

[silat]

What do y'all think about putting the transformers from that amp in the  6A20x2 Weber head?

http://www.tedweber.com/media/kits/6a20x2_layout.jpg

[sluckey]

Should work just fine. You'll need to modify the bias circuit slightly.

[silat]

Thank you Sluckey! I am pretty sure that is what I am going to do.