Tube amps for classical music FU29 vs EL34

Hello Bartokfan. I can concurr with M wilson's experience regarding bass response with both the el-34 and KT-88/6550 tubes. Grgm's solid advice on waiting until you get your speakers is a very astute piece of advise.Depending on your room size of course????....you will more than likely need a little more muscle,especially considering your speakers nominal impedence of 4 ohms. The jadis amplifiers are one of a handful of tube amplifiers that seem to respond well to a speaker with a low impedence due to there excellent output transformers and a 2 ohm tap.Most typical el-34 based tube amps will have a tougher time with 4 ohm load.The only el-34 equivalent tube that will give you the bass foundation and slam of a kt-88 is the original Genelec KT-77. The el-34 tube is a power pentode whereby the Kt-77 is a beam power tube like the kt-88 and can be succesfully substituted for an el-34 providing the screen-grid ratings of an el-34 are observed.Unfortunately... the Kt-77 is very scarce and typically very very expensive.Sonically.... the Kt-77 is a truly amazing tube when optimized in an el-34 circuit.It is even more liquid in the mids than a good nos mullard el-34 but possess's the bass drive and resolution of the Kt-88.The top end response of the Kt-77 is second to none and will easily trump any kt-88 or kt-90[genelec kt-88's included] Caveat....Using a kt-77 in a el-34 circuit will "not" give you any more power than an el-34. Best of luck on your endevour. Cheers David

Think of the KT90 as a 'heavy duty' EL34. A KT88/KT90 tube will have more bass than an EL34, as others have mentioned. They will also have more power, FWIW.

Interesting post David. What I was refering to in the EL34's is that they provide more bass than my friends single ended 300B Cayin(can't recall the tubes), which classical music sounded flat, IOW lacked a certain depth and height I'm looking for in an amp. So yes, I should get the speakers first, see how the Jadis responds. The Jadis lacks the deeper bass regions. My current speakers are 25 year old Philips 2 ways. Paper 8 inch cone, beautiful clear dome tweet. You hit on something about Jadis' transformers, the quality. IOW all transformers are NOT equal. And since this will be my "last amp" (notice I have the Philips for 25 years)I want to make it count. I don't make enough $ to trade off ,like you guys can. So ,seems its back to my orginal idea, a Jadis DA30/used, if business is good, new, sometime late 2005. The DA30 has KT88's. I'm sticking to my orginal plan, just got sidetraked alittle.

Aroc's post further confirms to stay on course with the Jadis DA30/KT88's. You see most of classical collection 400+ cds are not DDD/modern recordings. Some are from the 50's, some are Naxos, and others just don't have much dynamics. But still want to get all the music on a solid foundation = bass. I realize from listening to my friends 300B, big bass rolloff, that w/o a bass foundation, classical sounds flat. But as I say, listening to jazz vocals, the sound was "super-natural", but the slight bark in the male vocal threw me off. First time I heard a liquid smooth mid, but for those who like a "kick" in bass, will have fatique of a 300B amp. Another friend has a pr of old Conrad Johnson tube monos with Martin Logans, I believe Arius, again too flat. I'm really hoping the Seas Thor sounds alot better than these old smoky sounding Philips, I'm ready for a new experience. And then to take that experice even one step up to the DA30. My final system. I'll keep everyone posted as to the new Thor's. I use to post here a few yrs ago under the name tweekerman. I promised everyone I'd have new Thors,...well I'm finally close, good chance in July.

Personally, I wouldn't get too anal about the supposed differences between EL34's and KT90's (or 88's, or 6550's). IMHO its far more about the design of the amplifier these tubes are used in. One of the limiting factor of EL34's is that they produce roughly half the power of a KT90. Typically, an amp with 4 KT90's per channel will produce about 150 watts +/- and one with 4 EL34's will produce 75 watts +/-. Once you have picked an amp which will drive your speakers properly you can fine tune its sound by tube selection, and you will find differences between the types being discussed. FWIW in an amp which is designed to accept both EL34's and KT88's, KT90's and 6550's, I would agree with the general statement that the EL34's will have the smoothest midrange and sound weakest in the bass. The 6550's the most neutral, the KT90's the more "detailed" and the KT88's (which I use) a tad warmer and more airy than the former. But it all depends on the amp and, to a great extent on the small tubes used as well in conjunction with the power tubes.