Unsolved mystery: '62 Bandmaster modded along time ago

[Guns1rose]

Well, im not sure if you all saw the thread i did on removing the black paint from my '62 bandmaster, but long story short, i ended up opening up, to investigate why the amp would have a hammond organ reverb tank in it. The pots added for the reverb dated 11-68, so the mods were obviously done a long time ago.
These are some really funky mods, and i really have know idea where to start, but i really want to know what some of them could be for.

Alright so here we go.
The first thing i noticed that isnt in the schematic is the large cap on the Vibe channel volume pot. The small cap is something i added to make the channel a little brighter.



After the cap, it goes straight to the extra tube (12ax7) for the reverb.


(morecoming)

[Guns1rose]

Next, it goes in, and out of the actual reverb tank, into a random spot in the board.

[Guns1rose]

transformer for the reverb.




Now this is the mod that really stumps me...
Alright to the left of the powertubes (looking from the back of the amp) there is a spot, that looks like another power tube, or recifier spot. This is not in the schematic (6G7-a), and it is completley wired in the circuit!! There is no tube in it, there was no tube in it when i got the amp, but im confused as to how the amp could work with an empty tube socket.

[Groovey Records]

Can't see rhyme or reason for the Mod.

When it comes out of the tank and goes to the chasis it is a ground I believe

How does it sound

[Guns1rose]

Originally Posted by Groovey Records

Can't see rhyme or reason for the Mod.

When it comes out of the tank and goes to the chasis it is a ground I believe

How does it sound

sounds phenomenal. I will NEVER get rid of it.
Im just really confused about the extra tube socket.
Maybe i should just throw a 5u4 in it haha .

[Groovey Records]

Maybe converted from an earlier 5E7 bandmaster when they did use the rectifier??

Very weird

[imsilly]

Someone obviously went mod happy with it.

I had a much cleaner version of the same amp and it had an extra tube socket in it that was not connected to the circuit. The modder obviously thought, "Cool someone has left me a place to put a Tube Rectifier if I get bored of the Solid State one I already have, lets add a it to the circuit." I guess it makes sense, why not do that if you are adding a reverb tank anyway.

[muchxs]

WOW. Someone had some fun with that thing!

Love the extra socket on the power supply side. It looks like they just jumpered from one power tube socket from another, see what they used for wire? It's grey lamp cord. Very creative! Pretty sure there's a stock knockout for a rectifer tube in that location although the '60s Bandmaster had SS recto.

Next guess: They probably had a bad tube socket on that side so they just jumpered over to the new (ish) good one. I'd have to take a better look.

There's some pretty creative improv goin' on, those dog turd caps were probably salvaged from an old TV. Same with the extra sockets.

The reverb probably worked at one time. No point going through all that effort and stop short of makin' it work but who knows?

We got a saying out here, it goes "Tractor don't run... paint it!" Bandmaster don't run, paint it?

I was up at a farm last Summer, they had a dozen vintage tractors around the place all with shiny paint and fresh decals, Armor-All on the tires. I asked if any of 'em run, "Nope!"

Hey! Does that extra octal connect to the extra transformer mounted inside the chassis? MIght be the reverb driver.

[Papa Joe]

Looks like that empty socket is wired for the rec.Gotta be a rec. somewhere.DO NOT put a tube in in it.unless you want to see smoke..

[muchxs]

Originally Posted by Papa Joe

Looks like that empty socket is wired for the rec.Gotta be a rec. somewhere.DO NOT put a tube in in it.unless you want to see smoke..

Empty socket is not for a rectifier, count on it.

+100 on "Don't put a tube in it until you figure out what it is".

If I had the amp right in front of me I'm sure I could tell you more.

[David Barnett]

I can't figure out the purpose of an extra socket wired one-to-one with one of the output tubes. Unless someone was using it as a place to insert meter probes to adjust bias?

If it was my amp I'd remove ALL the non-factory mods.

I would imagine the Vibrato Channel does indeed need some added brightness, what with a .15 cap from the volume control to ground...

[Groovey Records]

There is this guy in Sterling Va. near DC that sells tubes at really high prices.

He works on fender amps too, he is pretty good. Mike K is his name


KCA NOS Tubes www.http://kcanostubes.com

Let us know what you decide to do

[Guns1rose]

Originally Posted by muchxs

WOW. Someone had some fun with that thing!

Love the extra socket on the power supply side. It looks like they just jumpered from one power tube socket from another, see what they used for wire? It's grey lamp cord. Very creative! Pretty sure there's a stock knockout for a rectifer tube in that location although the '60s Bandmaster had SS recto.

Next guess: They probably had a bad tube socket on that side so they just jumpered over to the new (ish) good one. I'd have to take a better look.

There's some pretty creative improv goin' on, those dog turd caps were probably salvaged from an old TV. Same with the extra sockets.

The reverb probably worked at one time. No point going through all that effort and stop short of makin' it work but who knows?

We got a saying out here, it goes "Tractor don't run... paint it!" Bandmaster don't run, paint it?

I was up at a farm last Summer, they had a dozen vintage tractors around the place all with shiny paint and fresh decals, Armor-All on the tires. I asked if any of 'em run, "Nope!"

Hey! Does that extra octal connect to the extra transformer mounted inside the chassis? MIght be the reverb driver.

The amp works perfectly fine, including the reverb. It gives beautiful swells.