Discovered an old Tube Amp

[simao.nogueira]

I found an old tube amp my grandfather had laying around, and decided to bring it home.
I plugged it in and the tubes lit up. There are four holes in the back, and I can't figure out which ones are the input or the output.
I'd like to plug my guitar into it, but if that's not possible, just use it as an amp with an aux input.
I don't really know what else to say, I'm no expert (at all really), but I'd like if you could tell me a bit more about it, and whether I can or not plug in my guitar.
I'll post some close up pictures, and, if you want, from the circuits on the inside.
Any feedback is appreciated.



UPDATE:
Here are some pictures of the amp:
https://drive.google.com/folderview?id= ... sp=sharing


Regards,
Simão Nogueira

[chocopower]

Man, you are lucky. Put voltages in a amp old like that without check works is really dangerous!!!

Before put yours hands in a guy like that i recommend you read a lot in forums like that or books.

Give us a bit more information about the amp. Model, gut pics,....

[Phil_S]

Don't power it up again until you understand what you are doing. Powering up an old amp like that is dangerous. Also, powering up without a properly matched speaker load plugged in can damage the transformers. You have a lot of reading to do. There is a sticky at the top of the forum.

That amp is a lucky find. Please be careful.

[simao.nogueira]

It had been tested a while ago, and I was well protected when I did the test (trust me, I took all the precautions) but I did not know I could harm the amp.
Ill upload some more pictures with this reply.
Im thinking about taking it to a professional here, so he can take a look.

https://drive.google.com/folderview?id= ... sp=sharing

[billc]

Looks like a natural for a 5C1 Champ build....6SJ7, 6V6, 5Y3 though maybe the tubes you have could maybe be made to work...can you read the markings on the two glass tubes?

[simao.nogueira]

Yes, the one on the left having the knobs pointed at you says:
418
422
(It doesn't seem like there or ever was anything else written)

And the one on the right says:
6X5GT (on the front)

3K8 (on the back)
432

[gui_tarzan]

The 6x5GT is a rectifier but even tubeworld doesn't show any of the others.

[simao.nogueira]

Any idea of what that might mean?

[David Root]

I read 6SG7 on the metal tube, not 6SJ7. Not seen a remote cutoff pentode in an audio amp before.