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    EDICRON EL34s??

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    GP49

    Posts : 718
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    EDICRON EL34s??

    Post by GP49 on Thu May 07, 2009 11:49 am

    Has anyone here ever seen or heard of "EDICRON" tubes?

    While rummaging around for some old stuff, I found, packed away among a bunch of NOS GE 6550s, two NOS EL34s which were branded "EDICRON."

    The boxes are dark blue/grey, labeled "Edicron london Electronic Tube" and "Edicron london Electronic Valve" on alternating panels. The tubes have narrow glass envelopes with flat tops (that is, not rounded on top like my JJs) and the printing on them says, "EDICRON EL34 N8WN8." The silvering on the inside of the envelopes extends down about 1/2" from the flat tops.

    I put them into my Dynaco Mk II just long enough to see how they bias up and to verify that they work and aren't shorted. Without changing the bias setting where I run my JJs (45ma per tube) they ran at 65ma per tube.

    Does anyone have any knowledge or experience with "EDICRON" EL34s, and whose factory these may have come from? "EDICRON" is apparently a marketing company that sources its product from all over. Various sources on the Web suggest the source may be the former Yugoslavia (both EI and JJ are mentioned) or Russian. There is no country of origin marked on the boxes or tubes. "EDICRON London" isn't going to fool me. I'm certain that these are not Mullards!

    Bob Latino
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    Re: EDICRON EL34s??

    Post by Bob Latino on Thu May 07, 2009 4:10 pm

    Edicron, I believe, as you have stated is just a reseller of tubes probably from JJ or some Russian source. Ruby Tubes in the USA is similar. They are (to my knowlege) Chinese tubes. The Ruby GZ34, by the way, for the ST-70, Mark III etc. is a very good and durable tube. A lot of guitar players use Ruby tubes. Their EL34 is supposed to be able to take 600(!) volts on the plates.

    Some tubes do draw more current and the amp must be rebiased when you change output tubes. Anytime you change the rectifier the bias will have to be adjusted also.

    Bob

    GP49

    Posts : 718
    Join date : 2009-04-30
    Location : East of the sun and west of the moon

    Re: EDICRON EL34s??

    Post by GP49 on Thu May 07, 2009 5:49 pm

    THANKS, Bob.

    I figured once these Edicron tubes biased up SO differently that they weren't JJs. Besides, the glass envelope is definitely different.

    As to the Ruby Tubes EL34 taking 600 volts on the plates, that's not so impressive compared to the "real" EL34 specification of 800 volts on the plates. But I guess that only means that the original Mullards, and the other old ones by Siemens and such...and rebranded siblings...can handle that, not the current Chinese/Russian/Eastern Europe production.

    My Dynaco Mk IIs with beefed-up power supplies (greatly increased power supply reservoir capacitance) run their EL34s' plates at 501-508 volts. Some of the increase in plate voltage over spec is due to the power supply, some to higher AC line voltages now, vs. 1955. I bias them at 40 to 45mA per tube.

    kevco

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    Join date : 2009-07-16
    Location : Aldan, PA, USA

    Re: EDICRON EL34s??

    Post by kevco on Sun Jul 19, 2009 10:52 am

    Bob Latino wrote: Edicron, I believe, as you have stated is just a reseller of tubes probably from JJ or some Russian source. Ruby Tubes in the USA is similar. They are (to my knowlege) Chinese tubes. The Ruby GZ34, by the way, for the ST-70, Mark III etc. is a very good and durable tube. A lot of guitar players use Ruby tubes. Their EL34 is supposed to be able to take 600(!) volts on the plates.

    Some tubes do draw more current and the amp must be rebiased when you change output tubes. Anytime you change the rectifier the bias will have to be adjusted also.

    Bob
    I'm using a factory matched quad of Ruby EL-34STR's in my modified ST70 at the moment. One of the tubes has a severely malformed glass envelope that makes it look like it's leaning over. It obviously should have been pulled. They sound reasonably good, but bias tends to float a bit. Overall I rate them to be second quality tubes.

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