Pre-war amp, not sure of make

[vintagekiki]

[Helmholtz]

Right, that looks like a PP amp wiring, so the metal can tube should be a 6L6 as well.

[loudthud]

I would check that pin 8 of both "6L6" sockets are hooked together and go to that 200 Ohm resistor (or possibly one of the other big wire wound resistors) to ground. Also, pin 1 of the "6L6" sockets is probably grounded. This grounds the metal shield.

[thelonious_crunk]

What's the tall metal tube? You are making this very drawn out and confusing.

Nothing confusing already explained its a 6L6...how am i drawing this out any? Haven't used an older forum style in awhile...i thought we were all just having a normal discussion here

[thelonious_crunk]

Right, that looks like a PP amp wiring, so the metal can tube should be a 6L6 as well.

Yes its 6L6 and yes it has 3 terminals on speaker. So the unknown bottle Sylvania tube is 6L6. Do they have to be a matched set? I am not to new to playing, but newish to fixing.

[thelonious_crunk]

I would check that pin 8 of both "6L6" sockets are hooked together and go to that 200 Ohm resistor (or possibly one of the other big wire wound resistors) to ground. Also, pin 1 of the "6L6" sockets is probably grounded. This grounds the metal shield.

If the 200ohm resistor is gold, yellow, black, red then yes its there. I also see the grounds to chassis on the #1 pins

[Helmholtz]

Do they have to be a matched set?

Yes, especially in a cathode biased amp matching gives best performamce and max. output.

[thelonious_crunk]

Yes, especially in a cathode biased amp matching gives best performamce and max. output.

Ok, and any matched 6l6 set will do? I like Ruby Red and GrooveTube

[Helmholtz]

Ok, and any matched 6l6 set will do? I like Ruby Red and GrooveTube

In a cathode biased power amp (I think that's what you have) cathode degeneration stabilizes against tube and supply variations. So the brand shouldn't be critical.

[mozz]

You have a very long way to go in repairs before you start to worry about the output tubes being matched. Test your transformers, with a ohm meter first. Once you determine the power transformer is good, draw out your wiring to the speaker. Field coil, speaker itself, then the output transformer all need to be tested. It may have a hum bucking winding also. That amp is in really bad shape and chances are you won't be using that original speaker.

[thelonious_crunk]

You have a very long way to go in repairs before you start to worry about the output tubes being matched. Test your transformers, with a ohm meter first. Once you determine the power transformer is good, draw out your wiring to the speaker. Field coil, speaker itself, then the output transformer all need to be tested. It may have a hum bucking winding also. That amp is in really bad shape and chances are you won't be using that original speaker.

Good call, appreciate the help. Ok i will test with meter first.

[glebert]

Yes its 6L6 and yes it has 3 terminals on speaker..

Three terminals on speaker seems odd. I was actually wondering if this was a type of field coil speaker, but that would require four terminals I believe.

[Helmholtz]

I don't see a field coil speaker. To me it looks like an alnico speaker with the OT mounted to its frame. With a push pull amp, 3 wires connect between amp and OT primary..

[thelonious_crunk]

You have a very long way to go in repairs before you start to worry about the output tubes being matched. Test your transformers, with a ohm meter first. Once you determine the power transformer is good, draw out your wiring to the speaker. Field coil, speaker itself, then the output transformer all need to be tested. It may have a hum bucking winding also. That amp is in really bad shape and chances are you won't be using that original speaker.

Power transformer putting out around 39 ohms when power switch engaged. Fuse is working too. Will check the field coil, speaker, and output transformer once i research how to.

[thelonious_crunk]

I don't see a field coil speaker. To me it looks like an alnico speaker with the OT mounted to its frame. With a push pull amp, 3 wires connect between amp and OT primary..

The OT says "5999 PP" on it. Alnico would be nice