Tesla & Valvo 12ax7 ecc83 N.O.S. Are they real or fake?

[carloshaze]

Hi from Spain to everybody.

I just got this nice 18w tmb from an UK builder, that came with JJs. Sounds great, but i'm shure can sound much better with some nos tube.
Here is the amp:

http://www.mylespaul.com/forums/squawk- ... hread.html

http://www.mylespaul.com/forums/member- ... ck-uk.html



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I can get some of this Tesla & Valvo n.o.s. valves, but i don't know if they are real or fake.


Are they any good? better than JJs?
The guy that got the tubes is asking 20 euros for the valvo and 15 euros for the tesla. The shipping will be very chip, since he is on Spain, just 3 euros more.
I can get some more pics from the guy, if this help.

Or maybe i should try to find better preamp tubes for de 18w? Mullard, brimar, other teslas, GE.

Also I'm looking for the "best" el84. Teslas? Polams? Ei, RFT? for a hendrix, Trower, kossof, zeppelin and all late 60s 70s great marshall rock sounds, with a lot of beautifull and musical feedbacks.

Thanks a lot and sorry for my "bad" english.


Carlos.

[dotfret]

They two valves you picture look "right", although the Tesla is a relabelled RFT (there are a lot of them about, Tesla sold lots of these).

The prices are reasonable, assuming they really are NOS. They are both nice and sought after types. In an 18W they should sound better than JJs in V1 position - other positions are less critical, tonally.

You should find it hard to distinguish the Valvo from an old Mullard or Brimar - the Mullard is the same design, the Brimar is very similar, as are Tungsram. The RFT should have a slightly earlier break-up, but a nice smooth sound.

The "best" EL84? the only agreement is that the 60s Philips design (with rectangular slits in the plates) sounds a little smoother than the later Philips design (with round holes in the plates, sometimes called the 6BQ5 design). A lot of Polams and Telams were made to the 6BQ5 design. They still sound good.

I would use the JJ EL84 that the amp came with for now. Keep looking!

[carloshaze]

Thanks Dotfret.

More pics if this help.


This 4 pics from the valvos, and some codes that don't show on the pics are: 163 and 84L5 in some of them, and JBBA and 7H4 in others.
Also on the boxes are this code ECC83 2002293, if this help.



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And this 4 from the teslas, and the jj boxes don't belongs to them:



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So, what's the opinion of the "audience"? wish one are better preamp valves for an 18w tmb?
Actualy the guy whant to sell the teslas for just 10 euros or 12, depends if i get all of them, 4 in total.
He said that the valvos will be 20 euros each one, and in his opinion are really cheap.
To me i don't mind if they are 10 or 20 euros, i think are quite chip, so i just whant to get from him just the best.

Thanks a lot.
Carlos.

[dotfret]

Carlos, those codes have not been read properly - but this often happens.
I could see the I6 in the first photograph.

163
84L5 does not make sense, but I will assume that it is really
I63
B4L5 which is the code for a shortplate ECC83, made by Mullard in Blackburn - no surprise, Mullard and Valvo were both Philips factories.

I6 (often looks like 16) is an ECC83 code, 3 is a design revision number, B is the factory code, the remaining letters are a date code.
Valves made in the Valvo factory have a D code.

I cannot make sense of the other codes. The J factory code would indicate manufactured by Mullard in the old Tungsram factory in Edmonton, but the rest I cannot understand. If the valve were made there, I would expect the code to be of the form
f9?
J???

You should be aware that these codes are not completely known, and were sometimes re-used on a different type of valve, when a type became obsolete.

You want to make a decision?

Just one valve - buy the Valvo with the code I understand. A Blackburn Mullard has a much higher price than €20, and that is what he has!

At these prices, I would buy everything the seller has for sale! He does not know what the codes mean, and is telling you honestly what he sees.