Cheers James I will take a look at that supplier. NOS Tesla's hard to come buy.:)
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Cheers James I will take a look at that supplier. NOS Tesla's hard to come buy.:)
Not necessarily. Valves that meet minimum manufacturers standard were sold as new. Say they degrade 30% and now test at 70% they will be hovering around the replace mark. New valves that measured much better than manufacturers spec that were sold new, lost 30% of emmission, can still measure well above that minimum spec, so even though they are far from new and arguably sonically tired they will measure as or better than minimum manufacturers standard. That is why this spec, now often taken as a litmus for NOS condition, is really not.Quote:
Originally Posted by Ali Tait
However I do agree that a valve that measures poorly cannot be to minimum manufacturers standard and so cannot be NOS in any rational sense unless new old reject stock and should definitely be avoided...
I hope this helps some who find the world of valves confusing [emoji2]
Good point James. It's a minefield when considering the number of valves advertised as NOS and worse than this is that generalisations get heaped on one particular brand or other, elevating prices (or the reverse) when quite often there may be less sonically between various brands than meets the eye, given two different valves with the same specs and measurements.Quote:
Originally Posted by Jazid
The other point is that many valve designations were more performance specs than blueprints for a specific construction and various manufacturers followed their own designs for their own reasoning, giving some very specific performance specifications for similar valve designations.
The ECC83 has long been used for the gain stage in preamps etc and is a very popular valve with a fair few differing constructions, meeting the same electrical output values (give or take). It's when one examines the construction for things like microphonics and consistency of batches for tolerance, that one can start to generalise more accurately. This involves a fair bit of research and testing and I wonder if any one resource as yet has all of that info clearly displayed? There are a few sites I know of which get close.
I've largely given up trying to get any warranted tolerance matching for NOS bought valves and to a greater extent dont bother these days as they're so ridiculously over-priced (Telefunken 803s in particular but also some of the ladder plate Mullards). I look for low microphonic new issue valves, and in particular recommend the gold pin JJ803s for ECC83 positions over just about any new valve (it's based on the Tele 803s construction). A cleaner sounding 83 type I've yet to find. The new types though have their own issues regarding matching, and can be 10% out on tolerance so where important, usually worth paying to have closely matched valves sorted together.
The pic shows a few 12BH7A's I rolled in my Air Tight ATM2. The best, I thought, were the RCA black plates by the boxes on the far right. The plates are a very gloss black, maybe made around 1966?Quote:
Originally Posted by Jimbo
Mid-70's Mexican RCA 12BH7A were pretty good too. In that circuit:) Worth checking out sometime maybe.
Hi Paul,Quote:
Originally Posted by Reffc
oh, the joys of valves :)
Re; the JJ ECC803s they would appear to be a copy of the Tesla ECC803s which, as JAC music somewhat labours, is neither a frame grid, nor a close relative of the famous Tele ECC803s, but rather a variant of their long plate ECC83 using summat like Tesla's old tooling for their ECC803s which in turn was also not a frame grid. This however confers no implication from me on how it sounds or behaves which you have investigated and I haven't - I haven't even heard one AFAIK, so have that in my 'to do' tray which is currently about 8ft high :( We may be thankful they are good, at least one new ECC83 type is performing.
The only frame grid ECC83 production was from Tele as their famous ECC803s, and the Tesla E83CC. Since Tesla's demise the modern incarnation is the JJ ECC83s. I believe the original Tesla tubes have different metalurgy to the JJ ones and slightly different manufacture and glass, etc. The original Teslas are in my opinion fab sounding with low microphonics as standard. I do have a few of the JJ produced Tesla branded ones, but have never listened to them, that is also in the 8ft high list...Sadly the JJ ECC83s appear unloved by many who have tried them...
For the real obsessives there was a selected production stock of the old Tesla E83CC that got bought and branded by Mazda and these had gold pins. These may or may not be the same as the Tesla gold pin E83CC that some are selling nowadays; I have heard others (who should know) claim that the gold plating was added on the Teslas recently and no original stock was ever produced with them. I have some NOS Mazdas and they are old and of known provenance, the gold may or may not have been added at Mazda's factory for marketing, or Teslas, but it certainly wasn't added after original sale. They are very nicely made tubes, I have only tested mine, no reports of sonics.
Other notable frame grid tubes include the ECC88 and Western Electric 417a. The regularity of performance was the main advantage to manufacturers and electronics companies, this was achieved because the grid windings could be exceptionally consistent and fine, and the construction was well suited to (very high quality) mechanised manufacture. You can't even SEE the grid on a 417a without a magnifier, and it is spaced .045mm from the cathode and cathode to anode distance is only .58mm. No other winding method allowed such precision. In practice it was of especial benefit in double triodes where balanced sections, low noise, and linearity were (and are) highly desirable of course.
Hi James
yes, it is a Telsa copy, not the Tele as I mistakenly listed above...well spotted!
A little more data on the JJ 803s:
Product description:
The JJ/Tesla ECC803s Gold pin version is a hi-performance 12AX7 that has a spiral wound filament to reduce noise and hum. The construction is different from the JJ ECC83 in that the plates are more conventional, but have a special heat dissipating fin that serves to improve efficiency and gain. The plates of the tube are also longer as compared to most standard 12AX7 tubes. This over sized plate structure improves details in the bass and low mid-range responses.This is a premium sounding / high performance tube ideal for linestage preamps, mic preamps, studio gear etc. Long plated tubes are not suitable for combo/ high gain guitar amps because they can be prone to microphonics.
It's also a thick glass 12ax7/ECC83 type which is meant to further reduce microphonic risk, but as a long plate, it's still prone to microphonics so isn't recommended for guitar amps for that reason. It does make a superb audio amplifier valve though.
Data sheet (note the interesting comment "non-microphonic", yet it is a long plate type, so I don't buy the non-microphonic bit)
Datasheet
I've said this a few times - I had a pair of Tele ECC803S to see what the fuss was about and the Tesla ECC803S gold pins (not JJ).
I could not tell them apart in the Air Tight ATM2, even though the construction was different. Rare thing that I usually think I can when construction is different. I sold the Teles and made some money:)
Tesla tubes (not JJ) really are excellent - the top notch ones particularly as they produced different grades of various types.