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Posted

The BH uses EL34's and if the RCA's are really Mullards then they are very good tubes. They need to matched and tested though before even coming near the BH.

Posted

Yeah. :-\ I recently checked most of my Mullard stock and one of them is borderline so it's a good idea to have at least a tube checker handy. That tube has seen a lot of use in the old BH so may it rest in peace. :P

Posted

None of these (other than the EL34's) appear particularly valuable.

Tung-Sol 7867

These are about equivalent to the 6CD6GA. Decent power tube, but has a lowish screen grid limit. Could be used for a few watts in a power amp -- I wouldn't both for headphone duty.

http://frank.pocnet.net/sheets/127/7/7867.pdf

Here's a schematic using one, which you'll notice uses a lot of your tubes which may not be coincidence: http://www.triodeel.com/du1a475.gif

25C5

Another low power output pentode (much lower power than the one above). Might be useful for a transformer coupled SE amp of some sort -- good for a couple of watts pentode, or less than a watt triode.

http://frank.pocnet.net/sheets/127/2/25C5.pdf

Sylvania EL86 [box]

Close to an EL84, lower plate voltage iirc -- one of them is not going to do much for you.

Posted

:blink:

Oh, right. This thread. I, uh, still haven't taken any close up pix of the tubes. I might borrow my friends EF 100mm F/2.8 Macro lens for the purpose. evilgrin0023.gif I've been woefully busy tearing out the ceiling of my garage and installing insulation, which is not a job I wish on ...most people. While clearing stuff out to make room for this horrible project, I found two boxes and briefly thought I'd discovered another stash of tubes:

n3rhqs.jpg

2vmxyrd.jpg

No such luck, they're old projector bulbs, for 1960s-era slide and film projects. Pretty cool, but of no use to audio snobs. I'd better keep them away from Mikhail or he'll incorporate them into his next DAC. >:D Aaaanyway ...back to the salt mines with me.

Posted

The Cary SLI-80 variants use 5U4GBs as rectifiers (mine had the RCA as stock) and both the RCA and Tung-Sol have good reps in that application. Great find anyway -- and good luck with those pesky flying squirrels. I had reds in my attic last summer and their warfarin-preserved bodies persist in the insulation and heating ducts. And forget about using them as EL84 subs. Those fluffy tails heat up but fast.

best,

o

  • 2 weeks later...
Posted

Great shots! I wish I had a squid to hold my tubes. The Tung-Sol AU7 can sound very good, and the RCA EL34s too. Is "FW" a Phillips factory code? I've seen it on Amperexes and Valvos, and on some other RCA tube types, though I don't have many EL34s. Thanks and congrats again on the find.

k

Posted

Those EL34's are definitely Mullards, most likely XF2's or XF3's. You can see the markings etched into the glass on the RCA tubes on the bottom left side but I can't read it from the pictures.

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