Mullard ID?

[craigtone]

I recently bought some Dynaco amps on eBay and the EL34 power tubes and rectifier tubes are RCA and GE. The say "Made In Great Britian" on them. Is it safe to assume they are re-branded Mullards?

TIA ...

[mesherm]

Mullards will have a hole on the center of the guide pin.
They will have a code etched into the glass near the base.
It will read xf1, xf2, xf3, or xf4 above a 4 charactor code representing the manufacturing plant and date of manufacture.
The xf is the code for am EL34. The number following it is the revision.

[craigtone]

Bummer! The GE one is a Mullard, the other three are RCA's with no branding and no holes in the guide pin. I guess I'll re-tube it after all. How are the Mullard New Production EL34's?

[WA4SWJ]

Craig,

I have some new production Mullards in my ST-70 clone and they sound excellent to me. I had one flash over briefly but fortunately it didn't damage the tube. I installed some 100 ohm resistors in the screens and have had no more trouble so far.

The amp sounds great with them.

Hope this helps.

Regards,

[erichayes]

Hi All,

Don't be too distraught; there were no "skinny" EL34s made in the colonies. That means your RCAs were probably made by Amperex or Telefunken. To my knowledge, Tele didn't have a plant in the UK, but I believe Amperex did, or had some kind of joint venture with Mullard. In any event, don't get rid of those RCAs.

Sylvania made a big bottle 6CA7 in the mid '70s that I personally thought sounded better than the EL34s. But they also imported Amperex and Mullard EL34s at the same point in time, so you never knew what you'd get when you ordered a 6CA7/EL34 from a Sylvania jobber. Later on, GE did the same thing and, for all I know, RCA might have, too (we didn't have an RCA jobber where I was).

[EWBrown]

These new "Mullards" and "Tung Sols" are basically re-labelled Sovteks, or other "generic" brand Russian made tubes. Which doesn't necessarily mean that they are bad, just that it is misleading and ethically unsound marketing at work. I still have reservations about the "Fender", "Marshall" and other guitar-name-branded tubes, too, though this malpractice has been going on for quite a bit longer than the "new" "Mullards".

Also BOLO for fake Telefunkens, I've seen these show up as "white box" 12AT7s / ECC81s, with the Telefunken markings on the tube, but they don't have the little "diamond" on the base. These were supposedly made by Tesla back way before they became J/J. Smelly Tellys, I call them... Yellow_Light_Colorz_PDT_07

And, no, there were never any "gold pin" Tellies, these aberrations sometimes emerge from the ooze on E-bay, so be forewarned and fore-armed. Yellow_Light_Colorz_PDT_21

/ed B in NH