Tube guru's, what do I have here?

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Twilt

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This was hiding in V1 of an older 2203 I just picked up.

It has absolutely no markings on it..nota one.

I've done a lot of searching on the interwebs trying to figure out what it is.

The best I can come up with is either telefunken or a mullard variant. It does that flash thing when powered on. Im not sure if that characteristic is limited to just those 2 brands though.

It does not have a square/diamond on the bottom nor are there any etchings on the glass. So im really stumped.

It has 4 glass seams on the top. Not sure if that helps at all, but they were hard to photograph due to glare.

Any thoughts as to what this bugger is?

~Troy
 

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:unsure: No diamond on bottom... RFT? Audio Research? Eastern Bloc? Does it work?
 
It does work indeed....and sounds fantastic 👌
Probably the only thing I would worry about unless you're trying to sell it. Pretty sure it's telefunken derived (built on their old equipment in Yugoslavia) Could have been branded all sorts of companies. Pretty sure that's what it is from the pics. Good stuff.
 
Probably the only thing I would worry about unless you're trying to sell it. Pretty sure it's telefunken derived (built on their old equipment in Yugoslavia) Could have been branded all sorts of companies. Pretty sure that's what it is from the pics. Good stuff.
Right on. No, i definitely dont plan on selling it.
I was just super curious what it was.

The V2 and PI tubes in the amp are Billington Gold (chinese) ECC83s.
Probably will end up rolling some tubes in those spots. But that V1 is saying put.

Thanks for the info guys!

~Troy
 
It’s Ei. You can tell by the crimped glass at the bottom above the pins.

Ei (or long plates in general) sound great in the PI slot as well.
Right on. Thanks Psychodave!

That lines up with some things i've read as well. Just last night, I came across some info stating that Marshall used EI in some amps in the 80's and 90"s. Being that my amp is '89, your assessment makes sense for sure.

I will have to pop it into the PI and see what happens! Thanks for the tip!

~Troy
 
It’s Ei. You can tell by the crimped glass at the bottom above the pins.

Ei (or long plates in general) sound great in the PI slot as well.

Nice I didn't know about the crimped glass thing

I assumed EI because of 80s Marshall long plate but that's good info
 
One of my Crate Stealths came with two tubes that looked just like that. Whatever labeling that may have been on them was long gone. A local tech said they were Ei.
 
From what I'm seeing (it's been a while since I cared to remember everything I once knew... trying to start that back up)

You have what appears to be an older Yugoslavian (typically rebranded for RCA) sometimes referred to as an Ei or Electronkski (spell check)


Great tube if she's got life in her. Should help make the amp feel a little more "slippery" than chewy if that makes sense. Smoother than any highgain 7025, shuguang etc.
 
From what I'm seeing (it's been a while since I cared to remember everything I once knew... trying to start that back up)

You have what appears to be an older Yugoslavian (typically rebranded for RCA) sometimes referred to as an Ei or Electronkski (spell check)


Great tube if she's got life in her. Should help make the amp feel a little more "slippery" than chewy if that makes sense. Smoother than any highgain 7025, shuguang etc.
I have a BUNCH of other various CP tubes, and none of them sound or feel as good as this skinny little fellow. It just shines in the 2203.

It's punchy, crisp, shimmery and smooth all at the same time. Love love love it!
 
I have a BUNCH of other various CP tubes, and none of them sound or feel as good as this skinny little fellow. It just shines in the 2203.

It's punchy, crisp, shimmery and smooth all at the same time. Love love love it!
There’s almost a “hi-fi” characteristic to some of those…. I’ve actually pulled out German telefunkens and put those in Marshall’s back when I had about 75 “NOS” tubes and would try various ones out.

All my amps were modded, mostly 800’s and plexis by splawn, soldano, Lee Jackson, FJA etc and truthfully, there wasn’t a rhyme or reason to which sounded better due to the way each amp was voiced.

Fwiw, the splawn mod (usually pretty identical) LOVED long plates at higher volumes than any “higher gain” tubes.

To the contrary, the lower gain mods like lee’s ate up cheap Chinese higher gain tubes. It LOVED those. Marshall was using those short plate Shuguangs oem for quite some time, not sure what they’re using now.
 
Looks like a LPS type 12AX7. If you have a camera that does negative filtering, try taking a picture to see if you can capture traces of the ink on the tube.
 
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