OK folks...time for a more balanced perspective on the use of the EL family of tubes in our amps, based upon a closer inspection of
facts!
But firstly, I appreciate your position on this
@UntilThen, and that of F-A, and applaud the recommendations to stay within the configured-for tube combinations. This is indeed the safest option for those who do not wish to 'stray' from that path, and I certainly do not expect/want anyone to take any unnecessary risks with either their Elise or Euforia.
But by the same token, I cannot see a great deal of time, effort and money totally negated without due consideration for all sides of this argument. And so in order to try and regain some kind of balance, I proffer my own stance, based upon what I regard as fairly solid facts that perhaps need stating/repeating...
As I see it, there are two distinct, and separate, topics that are most relevant here - firstly, the
safety of running these tubes, in light of recently stated
overheating issues (and which I have always proposed was
not due to the use of EL tubes; and secondly, their
actual performance
in real terms and different setups, as opposed to their not being specifically configured for our amps.
First...no-one questions the heat aspect that amps are designed for as part of the specification, and some can indeed tolerate higher running temperatures than others. Plus, the fact of running the circuitry at lower than usual temperatures is obviously no indicator of overall better
performance/sound...that is not the issue here. What my aim was in testing the 11/12 running temps was
purely to ensure that in no way could they be blamed for "frying" any of the circuits... with incontrovertible evidence based upon extensive measurement of the entire internals...to wit...
every single resistor, capacitor and section of the circuit boards ran 8 to 10deg C
lower with the ELs, compared to the 6SN7/6AS7G combo. The section immediately below the transformer ran over
25deg C hotter with the standard tubes. Both tests were carried out over 5hrs+ continuous running of each combo at high listening levels, at an ambient temperature of 23deg C.
This would indicate to me, at least, that we do not have any worries on
this score lol!
Second...regarding F-A's "surprise" at folks actually liking the sound of these tubes, I think the fact that a good many
did (and probably still do, despite not repeating their own comments here
) possibly indicates that F-A simply didn't have sufficient time to trial them fully, given their extremely busy schedule at the time...especially as these tubes do need a lengthy period to "settle in" before performing anywhere near their best. Plus, they only tested the EL11 drivers, and therefore paired them with 6AS7G powers, not EL12s. I personally have found the 11s are MUCH happier driving the 12s, and then deliver a much better overall performance.
I myself have been running EL tubes
continuously in Elise, and now Euforia, for a very long time - longer than anyone else I imagine - and without the slightest hint of trouble whatsoever. Of course, this is no cast iron guarantee there will
never be any problems, but this is also true of ALL tubes and amp circuits. And as overheating of the latter by these tubes can probably now be fairly safely ruled out (and which appears to be the main, insidious tube-related cause of failure), any hint of the amp not being "happy" with them would surely become noticeable to the trained ear...and my own amp is
more than happy with them - all the more so since my recent upgrades to the system!.... Further info on my own findings compared to ECC31/GEC CV2523 - mirrored by my Sylvania "Chrome Dome" 7N7 + NU 6SN7 driver combo - are in my recent post over at the Euforia thread.
Hopefully this gives a bit clearer/more balanced view for folks still interested in these 'alternative' tubes...probably the least 'risky' of pretty well any other such tubes we have experimented with these past years...so long as one isn't unlucky with the tubes in the first place, being somewhat more unreliable than your average old tube! Which is why one needs to be as sure as possible of easy returns if they should prove faulty!!
I repeat my joy at seeing so many folks really happy with the recommended tubes, and at how F-A have managed to bring out the best in them...both here in Elise land, and now in Euforia. They have indeed worked wonders...and all that remains for me myself is to see just how much further my amp can go with the Hugo 2 DAC/Amp in place....
when it arrives, lol!!!....CHEERS!...