[eichlerera1]

This is a letter I recently wrote to Bob Pletka, president of Eurotubes.



Bob,

I notice that there are not a lot of customer comments regarding the usage of JJ Tubes in a Hi-Fi application. Well here's my take on using the JJ 12AT7 and E34L's in my VTL 225 monoblocks powering Hales Signature 2 speakers.

Originally the amps were tubed on the output with GE Fat Boy 6CA7/EL34's (8 per amp). When I consulted with you I learned that the GE version was not a true EL34 tube, but rather a kluged up version of a 6L6 adapted for EL34/6CA7 usage. The original 12AT7 was by EI (actually not a bad tube in this application). At any rate I took the plunge and replaced them all with JJ's.

The amps have truly been transformed. Throughout the entire frequency spectrum the sound has been tightened up. The increase in detail was very evident. The midrange is a bit more forward but not in a "Brightness" sense. It is just more clear and detailed. With the new E34L's in place, it became evident that the punchy bass exhibited by the GE's was a bit bloated with too much bloom. The bass with the JJ's is much tighter and natural sounding. The treble was more extended and much less hashy. The harmonics and overtones are wonderfully articulated, again very natural with little artificial bloom.. There is a great sense of width and depth within the stereo image. It took me about a month to get used to this "new" sound. I noticed it took a little longer warmup time until the amps became dialed in but the extra wait was well worth it. The VTL has actually gotten closer to a transistor sound due to it's increased detail retrieval capabilities. Both tube types are extremely balanced throughout the entire frequency range. I must say I am impressed with the quality (and the price!).

I would like to tube roll the JJ 12AT7 with the long life Telefunken version but they are very expensive and tough to find. I am sorely tempted to cryo treat the JJ 12AT7 and if I do I will report back.

Thanks for your advice. You were extremely helpful.

Paul Galli


These tubes are worthy of your consideration when considering replacement and Bob is quite qualified (and willing) to discuss your tube needs.

[BikeWNC]

I am currently using JJ E34L tubes in my Dodd Audio amp.  I also have a quad of Svetlana cryo EL34.  The difference in my amp between these to tubes in quite evident.  The Svetlana tubes are more extended at the extremes than the JJs but are also a bit cooler and don't have the wide soundstage your mention of the JJs.  The JJ E34L tubes are more punchy or lively, the bass is not quite as tight as the Svetlana's nor do they have as much sparkle on the top.  But, and this is important to me, the midrange is more shall I say illuminated in a way that places each instrument in its own capsule of space.  The JJs are a bit more forward than the Svets but I agree the also produce the depth of the recording better.  Both are very good tubes and taste and synergy will decide which works best in any system.  Right now, the JJs are sounding really nice.

I am using Tungsol 5687s for drivers but I also have some GE 5 star and Raytheons to try.

[eichlerera1]

Speaking of 5687's, if you want a pair of Cryo'd Tungsol's, get in touch with Modwright. I think they sell them for $30.00 a pair. Dan uses them on his CD/DVD modded output stages. I think you'll like them.
                                                                         Paul G

[BikeWNC]

Paul,

Thanks for the tip on the 5687s.

Andy

[GRD]

I've had good experience with JJ 12AX7 and recently 12AU7 in 2 phono stages (Cornet and ASL Mini-Phono).  I haven't gone the real high end NOS route, but I have tried Raytheon, GE triple mica 5751 (grey plate) and Svetlana for the 12AX7's and I prefer the JJ's.  I've also tried a number of 12AU7 in the Cornet (RCA clear top, Tungsol, Toshiba) and the JJ is right up there.

[brucegel]

I think the reason why teslas don't get more play is because they don't cost 75 bucks apiece.I should shut up before they jack up the prices.I love them.