Replacing amp speakers with a tranny mounted on them

[inverseroom]

If you have to replace a speaker in an old amp that has the transformer mounted on it, can you use a regular speaker? Do you just remount the tranny on say the cabinet, then run the two wires to the new speaker the same way they were attached to the old?

[djimbe]

Do you just remount the tranny on say the cabinet, then run the two wires to the new speaker the same way they were attached to the old?

Yes, basically. Make sure that you're looking at a "regular" non-field coil speaker though. 'Cause field coil speakers have a traffo looking thing on them.

But, in something like an old Silvertone combo...like a Meteor amp or one of the guitar case amps...those often had the output transformer mounted on the speaker since the amp chassis was so tiny. I fixed a Meteor for a buddy once. Someone did a hack job fixing it before it fell into my hands. Old "repair man" replaced the (presumably) blown speaker with the attached output tranny with a modern speaker. My buddy couldn't unerstand why the amp didn't work. It was hard explaining to a non-technical guy that a tube amp needs an output transformer to work, and his didn't have one any longer. Got a replacement output traffo, mounted it in the cab, hooked it up, and my buddy was back in business...

So good the little Silvertones. The mic don't know how big that amp is...

[inverseroom]

This is a dual-6V6 Valco from the late 40's. I don't believe it's a field coil, just an amp with the output transformer outside the chassis.

I don't know if the speaker needs replacing--overall the amp sounds tremendous. But at certain frequencies, most notably the the notes surrounding A, on the bottom two octaves of the guitar, the speaker buzzes in a spitty way on the decay. it's really weird. I tightened up the speaker mounts, and tightened the screws holding the chassis to the cab, but it remains, this strange papery buzz only on certain notes.

[inverseroom]

If it were a field coil, it would have wires wrapping around the hub of the speaker, right? The way this amp is set up, there are only two wires leading from the chassis to the tranny, and then two bare wires from the tranny to the speaker.

[inverseroom]

Well, in any event, I am not going to need to get a new speaker. I took the amp apart to clean it and put in new grill cloth and cleaned a ton of dust and debris out from between the cone and frame...that was causing a lot of the buzz. There's still a little, but the amp is made of thin plywood and is sixty years old, so there's only so much I can ask.

[djimbe]

Yeah, you got a standard speaker there. Valco's can be cool. Old amps and their incidental noises though...I got a Gibson GA-8T that has something similar going on from time to time...

[pineyb]

Often that slight buzzy distortion on the decay is the result of some bad caps... sometimes a slightly dropped voice coil.... and sometimes just dirt and loose parts. I love old Valco/Supro amps, they are definitely worth fixing up.

[inverseroom]

This one is not from bad caps...I opened the thing up, it's been 100% recapped with fresh electrolytics and orange drops.

Amazing amp. Instantly the best clean sound I have ever had, and it breaks up like a mofo.