SET amps with cajones and finesse
Atma-Sphere S-30 or M-60 These OTL designs like high impedance speakers. If necessary, you can raise the impedance of your speaker by using ZERO autoformers. |
DeHavilland makes a nice 50-watt SET using a big Russian transmitter tube. They (and a number of other manufacturers) also make amps using the 845 tube, which is about half as powerful. http://www.dehavillandhifi.com/ Wavac makes SET's up to 150 watts, but they don't exactly give 'em away. http://www.tmhaudio.com/ If you don't have a DeHavilland dealer nearby, suggest you contact Brian Rovinsky of St. Cecilia Sound in Florida. Great guy. http://www.scsoundgallery.com/ |
I would echo the idea for an 845 based SET. They will give good power levels but still retain the SET architecture with a single output triode per channel. This is important(IMO) for the coherence that SETs are known for. The WAVAC would be an excellent choice(IMO), but they are pretty expensive(but very good). The Antique Sound Labs AQ-1009 is an 845 SET that is highly regarded in reviews and doesn't cost nearly as much money. A 90db efficient speaker should be able to produce peaks of 105db with 32 watts at 1 meter(not including room reinforcement effects). |
For 90db efficient speakers you definitely need a SET with highr output than 1-5 watts. Those tiny SET's are better suited to Klipshorn's or Avantgarde's with 100db+ efficiency. Now getting finesse out of a 40watt SET is something different. Good reviews of Cary products & Atmasphere, but nothing is cheap where you're going. Enjoy, Bob |
Good call, Wellfed! I was still thinking "inside the box" when I typed out my response above - hadn't seen your post at the time. Yes I have a pair of Zeros for my M-60's, and with especially difficult speakers they make a very substantial improvement. Just for the record, Atma-Sphere amps are not single-ended triodes, though they often compete against 'em. They use two back-to-back output transformerless class-A biased triode amplifier sections operating in a true balanced configuration. Disclaimer - I peddle 'em. My limited experience with Talon speakers suggests that the Zero autoformers would be needed if you wanted to use the Atma-Sphere M60's, as the Talons are likely to be a difficult load (judging from the struggles of a well-regarded conventional tube amp to drive a pair of Khorus X's). With the Zeros, a pair of M-60's would definitely be competition for a good high-power SET. I couldn't reliably speculate on which would work best with the Ravens. |
I don't mind being the lone argument; against.---A 25 wt. set will give you magical midrange.---Just expect zero slam for rock music. Your cross over and impedence are why.--I'm driving Montana eps at 92 sen.--- with the Sophia Princess 845. My impedence drops to 4ohm. Thank God it isn't the only amp I own. So if you are used to powerful push pull triode or solid state you'll hear what I'm talking about. If you buy one; buy other speakers. Don't sell that SS amp;you'll miss it. |
I beg to join Avguy; if there's a way to bi-amp your Talons, then use a medium output set for the highs & keep the ss for the bass. If not, you'll have to dish out giga$ for a very hefty tube that can provide voltage & energy at low frequencies. IMO, OTL is a good bet because power SET's prices are exponentially linked to two incosequential things called PS & output tranny:) While all amps have PS, at least OTL's lack the second (as an indication, retail for excellent output trannies for a 300B easily reach $2k -- that partly explains prices for the wavacs of this world). Cheers |
Avguy does make the most important point. A speaker's rated efficiency is only 1/3 of the question. That speaker has to have a very benign impedance curve and phase angle through the crossover in order to properly use an SET of under, say, 35-40wts. A speaker with 90db eff. but a difficult imp. curve and phase angle will not respond to a 5-20 wt amp. I have ProAc 2.5s which are 87db but have an extremely easy imp. curve and phase angle - I easily drive them with a 9 wt AirTight 300B amp. I am in a small, plaster room, though. |
Despite the high sensitivity of the Klipsch horns, the large woofers REQUIRE high power. While I have a pair of AtmaSphere OTL amps, I will say I have tried the Zero autoformers in my system, and they really bleached out the sound, and robbed the Atmas of what they do so well. The end result was clear and fast and sterile, and, well... it was if they became a solid state amp. I will agree that an 845 based tube amp will also be a great suggestion. The ASL 1009 I have heard combined incredible slam and lovely sonics. |
