Interesting information about EL34s

[Lake Placid Blues]

http://www.tube-classics.de/TC/Tubes/Valvo EL34/EL34.htm

This is a photo gallery of old EL34s. What he mentions about the history of EL34s being EL60s with a different pin out is not well known. Philips and Mullard were the same company. Philips factory was in Holland and the Mullard factory was in England. Several brand names were used.

Page on German EL34s:

http://www.tube-classics.de/TC/Tubes/SieTel EL34/EL34.htm


Interesting that he says, and there is no reason to doubt him, that Siemens never actually built their own EL34s, but rebranded EL34s from Philips or or Yugoslavia (EI). So most Siemens are actually Philips/Mullard. The original Siemens EL34s in my 1987 Silver Jubilee look like the rebranded Philips shown. When I first had my bias re-set using a scope on the Jubilee in about 1990 or so, the tech who was a university electronics engineer professor said the were Mullard-Philips. That didn't seem plausible to me at the time but maybe he knew more about vacuum tubes than I thought. East German RFT EL34s may have been rebranded by Telefunken?

 

[Gearjoneser]

Re: Interesting information about EL34s

I still have a few used Siemens EL-34's from my 87 2555.

I sure wish we had all the information back then that the internet provides us today.
I wish I'd had a bias tool back then.

Back around 1990, electronic classes stopped teaching tube tech because everything was moving away from it.
All I learned about was transistor circuits.

 

[Lazarus1140]

Re: Interesting information about EL34s

Back around 1990, electronic classes stopped teaching tube tech because everything was moving away from it.
All I learned about was transistor circuits.

That's disappointing but good to know. One of my goals in retirements was to take classes in electronics so I could learn more about amps. I might be better off finding an amp builder to work for - trading labor for instruction.

 

[Lake Placid Blues]

Re: Interesting information about EL34s

I still have a few used Siemens EL-34's from my 87 2555.

I sure wish we had all the information back then that the internet provides us today.
I wish I'd had a bias tool back then.

Back around 1990, electronic classes stopped teaching tube tech because everything was moving away from it.
All I learned about was transistor circuits.

Yeah, I didn't know jack about any of this stuff back then. I was totally dependent on taking my amp to a tech for bias adjustment and stuff. From what I have read, how we bias amps today with bias probes, and with amps having the 1 ohm resistors between cathode and ground built in with bias points from the factory, didn't really exist back then. It was usually done with a scope. For mass produced amps they just set the bias voltage to a set level on a voltage chart, that was determined from using a scope on a prototype with the typical tubes, or in the case of Mesa the bias voltage fixed by hard wired resistors. I read that it was Ken Fischer of Train Wreck amps that suggested a better way because of the inconsistency. We have him to thank.

A lot of Marshalls in the 80s came with what look like these East German Telefunkens:

http://www.tube-classics.de/TC/Tubes/SieTel EL34/EL344.htm