EL34 tubes Vrs. 6L6 tubes

I run an Esoteric Audio Research 834 tube integrated amplifier with EL34 tubes. It states in the owners manual that it also takes 6L6 tubes. Anyone know the sonic difference?
Also, I run Tesla JJ EL34 tubes, any suggestions on tube brands?

Thanks Paul
EL 34 is the European designation for the USA 6CA7.

The 6L6 is the USA version of the European KT 66. The best KT 66 is probably the MO Valve or Genelex, and should sell for about $100.00 NOS.

The best EL34's are Mullard and Amperex. Bought used you should be able to get 80% (of new test) for as little as $40.00. New in the original box with test papers could run $200.00 each. It is really all over the place on price.

The Russians currently build a 6L6 that is reasonably priced and sold under the Svetlana name. I personally doubt it would offer performance gain over the Tesla, but I have not made the test in that circuit.

There is a Chinese version of the KT 66, and even offered with brown base, no doubt to honor (or copy) the MO Valve. It has not been spoken of too highly among those I discuss this with, but that would be another affordable test you could make.

I run MO valve KT 66 in place of the (stock) Russian EL34 supplied in my Aesthetix gear. When I first switched these out I was astonished at the improvement. Later when I substituted Mullard EL34, I had a difficult time deciding which I preferred.

If my experience transfers to your gear, the lesson here is that Mullard, MO Valve and other new old stock tubes offer substantial improvement over the original Russian tubes, regardless of which you choose.

If cost is an issue, the Telsa is terrific and priced very reasonably. If you must try other enexpensive EL34 tubes there is Sovtek, Svetlana and Electro Harmonex.

My tests with all these tubes in Wolcott amps, proved the Tesla E34L over the Russian tubes, and ranking below both the Mullard and Amperex NOS.

Let us know how you do, especially if you experiment. It would be nice for others visiting this site to read results of your trials for this particular amp.
Call the manufacturer and ask how many volts are going to the plates of the 6L6. If it is not more then 320v, try some NOS RCA,Tungsol or Ken-Rad 6L6G. These have a very different sound then the EL34's and once you hear the difference you might never go back to the EL34's. They are very musical and give wonderful body to the music. Please check with Esoteric first. Leave the 6L6GB and 6L6GC alone. Try the 6L6G or 6L6GA. They are a bigger tube being the shoulder variety so make sure they will fit in your amp before buying a pair or quad.
Good luck,
I thank you for the input. I am currently searching for nos 6l6 tubes. I will advise you of the results.

*** I would like to mention that I have run tube amplifiers since 1975. I Started with Audio Research D-51, went to a D-75, D-76, experimented with Dynaco stereo 70's, back to ARC D-76 and D-51. I loved the 76 but wound up selling the D-76 after the old stock tubes wore out. ***I replaced the worn tubes with Russian tubes and the sound was hard and metallic, similar to a solid state amp. The amplifier never sounded musical with Russian tubes. I replaced the Russian tubes with Tesla KT-88's and it sounded pretty good. I guess the old tube designs contain some hidden secrets, or it could be in what types of steel were used in the making. Whatever it is, it just hasen't been passed on to the new tube manufacturers. I will keep you posted.
I found the 6L6's to be only slightly better in the mids. And when it came to bass it was non-existent compared to the el34. Try Svetlana el34's, in my amps they smoked the Tesla's
Can somebody tell me were I can find some EAR 864 for a low price (I'm from France) Many thanks. e-mail me please at : claro@univ-lille3.fr
The 6L6 will produce deeper tighter bass.

Go to www.eurotubes.com, they have the JJ6L6 and
it rocks.