Your choice of EL34's

Zaikesman, your observations are no doubt correct. As with all electronics, the end result of various tube tests, whether output or input variety, vary depending on the gear.

I performed the same test with the Svetlana tubes that you did, only with the amps I've already mentioned. They were somewhat better than the Sovtek and Electro Harmonex, but still ranked below the Tesla, and way below the Amperex, Telefunken and Mullards.

As with all things in high end audio, best that the end user does the final test for themselves. Tubes are a smart investment, last forever in storage while generally increasing in value.

What is not the perfect tube in your system today, may be tomorrow. Investing in NOS or clean premium tubes to have on hand for testing insures you are getting the maximum performance possible.

In fact, we all voice our systems to the associated gear. If you or I changed a major component such as the speakers, or moved to another listening room, we may well choose a different tube for one or another positions.

I must say though, that in my system I always prefer voicing with premium tubes rather than current vintage. The only exception is the 12 AX7 Sovtek. I continue to be surprised by its remarkable performance. I wish the same effort would extend to the 6922, 6SN7, KT88 and EL 34.

Perhaps in time.

Amperex double-D-getter, late 50's. Better than the Mullard "O" getter xf2 EL34s. I've not heard the "fatbase" xf1 or metal base Mullards but Amperex are the best I've heard. The Amperex are more dynamic and less vieled; two areas of weakness for EL34s. This was in my (then) VAC triode amp which I used for three years. I sold the VAC for a Moth SET amp. I found the SET topology and both the 2a3 and 45 output tubes superior to any of the EL34 tubes I've sampled.

Albert, exactly which Sovtek 12AX7 are you recommending? I was never impressed with them in the past, but I know they've introduced some new wrinkles in the meantime. My preference in new 12AX7's has been Yugoslovian EI ECC83's, though a person has to go through a bunch to find a couple of quiet ones. Fortunately, they are common at local guitar shops (when the country of manufacture isn't in chaos), so I can try several and promptly return the duds (if only I could do this with NOS!) I also tried the newish Teslas, but didn't like them much better than the Chinese ones (and had durability problems with these as well). The even more recent Svetlana version still awaits my audition.

What you say about a circuit's being intimately bound together with any particular tube's performance in it is undoubtedly the truth. So in fairness, I should point out (as I have alluded to in past forums that touched on this subject) that C-J techs advised me not to run the Tesla EL-34's in my MV-55, because their tests showed that only the Sovtek was up to the demands of this circuit (I suppose this has to do with biasing). I went ahead and ignored that warning, since the Teslas clearly sounded better than the Sovteks in the amp, and since I had always found C-J's tube replacement kit choices for my preamp to be seemingly based mostly on dependability of supply rather than sound (and I can sympathize with their need in this). Now the fact that the Tesla still managed to sound better than the manufacturer's recommended brand, albeit while not lasting as well in the circuit, led me to assume that I was not compromising its sonic potential and that C-J was just playing it safe. But I obviously cannot rule out the possibility that the Tesla tube might be able to give even more of itself in a situation where it was operated more comfortably within its (claimed by C-J) design specification. Luckily for me, the Svetlana made all this moot, and I have wondered why C-J never made them the OEM choice in this model, given that they have used Svetlana 6550 types in their bigger models. Maybe they still thought the Sovtek was going to last a little bit longer here - or maybe they just didn't want to buy a more expensive tube for a two-grand product.

Mwalsdor, I have a good friend who has the exact opinion as you concerning the double D getter Amperex tubes. In the Tube Research and Wolcott amps I preferred the Mullard XF 1 and 2 over the Amperex, but then again, it is a circuit thing.

The Tube Research was supposed to be magic with KT 88 and even KT 90 tubes. I tried all of the current tubes, Svetlana, Tesla, Sovtek, Ruby Tubes and others, only to be disappointed with all of these.

Of the batch, the Svetlana 6550 was the most reliable and biased up the best. Still, the sound was extremely disappointing, compared to Tung Sol 5881 and Mullard EL 34, the best sound I ever got with that set up.

Needless to say, I had complete sets of every current new construction EL 34 made, and tested for nearly three months.

Guess it is safe to say that testing in one's own system with as many options as possible is the best course of action.

Zaikesman, the Sovtek that performed so well was the 12 AX7 LP. This specifically in the first gain stage of the Aesthetix Io phono preamp. The ones I have had good experience with come from Jim White, the owner of Aesthetix, who selects them for extra low noise.

Quite necessary for this position in a high gain phono circuit, even with the best of the NOS tubes, and certainly for inexpensive tubes like the Sovtek.