Help identifing this tube

[bill0287]

Hi. I pulled this tube out of a Marvel (by Premier) 35 amp. Can anyone help me identify what it is and what a replacement for it might be. There is no other visible markings on it besides what's in the attached photo.

[g1]

What are the other tubes in the amp?

[DrGonz78]

It’s probably a 6v6 as I think the rectifier tube on that amp is a 6x4. We just had a question about this on the forum a few days ago. That’s why it’s still fresh in me brain.

edit: I think the preamp tube is either a12au7 or 12at7. Unless some of the models used big bottle preamp tubes.

[glebert]

This ad (https://reverb.com/item/3946979-vint...good-condition) says the tube set is 12/AU7/6V6 GT/6X4.

Gonz beat me...

[g1]

Apparently there were some older units with 6SL7, 6V6, 5Y3.

[bill0287]

What I pulled out of this amp was an unidentified 12AT7, a GE 6X4, and the one pictured above.

[g1]

Then it's safe to say it's a 6V6. A magnifier might help you see if there is anything left of the number on it. Should be somewhere on the glass, can be right at the top. Sometimes a bit of breath fog will help show it.

[bill0287]

Then it's safe to say it's a 6V6. A magnifier might help you see if there is anything left of the number on it. Should be somewhere on the glass, can be right at the top. Sometimes a bit of breath fog will help show it.

I would agree with that. What's a decent replacement for it not too expensive? I just want to put new tubes in the amp before doing anything else. I see a lot of 6V6GT and 6V6S at tube depot, but not a lot of plain 6V6.

[g1]

What you have there is a GT. Plain 6V6 would be metal, 6V6G would be shouldered 'coke bottle' type. GT is likely period correct and also the most reliable option. Metal type is least desirable and prone to microphonics.

[Axtman]

Try breathing on the tube (like you do to fog your glasses before you wipe them). Sometimes markings will magically show up.

[mozz]

I wouldn't go buy new tubes just for the sake of them being new. Those old tubes, if still good, will be fine.

[Tom Phillips]

I wouldn't go buy new tubes just for the sake of them being new. Those old tubes, if still good, will be fine.

I strongly agree with mozz. Original tubes are often perfectly good. Diagnose first and then replace parts if necessary. Old tubes made by the classic manufacturers can often outperform the copies currently being made. Those old tubes were made with better materials allowing them to outlive the newer copies.

[bill0287]

I strongly agree with mozz. Original tubes are often perfectly good. Diagnose first and then replace parts if necessary. Old tubes made by the classic manufacturers can often outperform the copies currently being made. Those old tubes were made with better materials allowing them to outlive the newer copies.

Totally agree, but in my case I am not diagnosing an issue - the amp works fine. I bought the amp as a "test bed" to tinker with. So I am going to retube it and see what happens...re-cap it and see what happens...etc...

[stokes]

I'd go with the re-cap first. Quite often these used old stock tubes are far better than current production.