$$$Sensitive Speakers with $$Amps?

I own a pair of Hornings, the product previous to the Aristoteles, that I use in my second system. Given their resolution, the quality of amplification certainly does make a difference.

My opinion regarding amps that retail for $20K - 40K is they are often boutique products and/or produced in countries (often, Europe or Japan) where a price premium gets applied. While you don't need to break the bank to drive them, you don't want to aim too low, either. And, as a surprise to some, due to the onboard woofers, you want to give the Hornings some power as well, more than you might consider otherwise. You don't need to go overboard, but in order to not have them come across as unbalanced in a bright way, you don't want something limpwristed.

Push pull tubes seem to do best with them. Triodes generally are better than pentodes, though my Jadis DA60 and Dynaco ST70 marry well with them, for whatever reason, my Jadis JOR and DA30 not so good. I own a cheap Chinese 6AS7G push-pull integrated from Jas that also makes me happy. Best of all was a Deja Vu 15 wpc push-pull 2A3.

I also have spent a fair amount of time with Jacob George of Rethm. Should you go in that direction, you can away with less power than the Hornings, due to either not having to drive any woofers or having them powered for you. Still, aim for quality, as the Rethms will reflect your decision there.

Kennythekey, in what part of the country are you located?

Since you have the motivation to visit Jeff Catalano, I fully encourage you to do so. You'll have an absolute blast! Jeff's a great guy, representing some of the more interesting yet least encountered equipment. His place, literally in the shadow of the Brooklyn Bridge, is something of a historical landmark, filled with more records than you'll believe.

Though difficult for me to explain in objective terms, something certainly exists with both backloaded horns and transmission line bass alignments in that they behave in a more complex pattern in terms of the load they present to a partnering amplifier than do sealed, ported, and front loaded horn loudspeakers; all those operating in a far more simple way. Then again, it should appear logical that what happens after the electrical impulse excites a driver's voice coil will be different as the driver's backwave has to travel such an incredibly far distance in comparison. The simple, electrical, numbers living on a stat sheet fail to capture this phenomenon. At any rate, let us understand that how the amplifier interfaces with the loudspeaker will determine how effectively, or not, that air mass propels down the labyrinth.

As Bud Fried stressed, a backloaded horn and a true transmission line are the exact opposite of one another. In simple terms, as the name implies, the area of the horn increases exponentially in size as we traverse it, whereas the transmission line decreases exponentially.

My experience shows that some amplifier topologies work better with some loudspeaker alignments than others. Representing a company producing a wide range of amplifiers allowed me to play in a way where differences in parts and the designer's approach canceled out. By that I mean, the amplifiers used parts from the same manufacturer and type, and the amplifier circuitry would be shared across differing products. Obviously, when comparing a push-pull pentode design to an SET, you would find the expected disparities. However, when comparing a 211 and 845 SET or 2A3 and 300B PSE or push-pull, we were dealing with almost identical product.

What initially surprised me was that the company's very powerful 78 wpc push-pull triode/pentode switchable amplifiers paled in comparison to the ability to put power into a backloaded horn next to their modestly powered 15 wpc 211 and 28 wpc SET. The 300B 8 wpc SET and 16 wpc PSE wound up closer to the 211. Now, who would ever believe that an SET could outmuscle a push-pull amp in a drag race? Yet, across the speakers of three different companies, the trend held up. Strange to see, but it actually came across as if the PP amps felt like a runner or bicyclist struggling for air when climbing a steep hill. These amps just could not get over the hump. This demonstrated there really is something to the SET phenomenon that those who denigrate their low power on paper have not yet realized. In somewhat of an analogy between tube and solid state, I believe the SET kind of power is actually different in a way we have thus far failed to be able to measure.

The transmission lines displayed conventional (and expected) performance.

Again, the OTL amplifiers we used (not only Atma Sphere - note: the A/S were 2004 and 2008 vintage) behaved the way I described in an earlier post. One big surprise that I didn't mention, even with the nominal 4 (dipping to 2.3) ohm load of one of the true TLs, the OTL amplifiers, even the 30 wpc Atma Sphere S30, outshined more powerful transformer coupled tube amps in virtually every case. Of course, just like people I know who power their B&W and older Wilson (newer are much better) speakers with OTL amplification, just because it's done, doesn't mean it's good.

In the end, as the saying goes, it's horses for courses...

Kenneythekey, I'm impressed in the most incredible way by your willingness to travel all the way to the East Coast to hear the Hornings. Indeed, the bravo goes not to me, but you! It's exactly THAT kind of passion that makes this hobby so wonderful.

With RMAF so close, September might not fit the plans of either you or Jeff. But if you can swing it, the annual Feast of San Gennaro http://www.sangennaro.org/ is a very short walk, and something not to be missed. After San Francisco (never visited, but it holds the reputation), New York probably has the most interesting Chinatown in the country, and also sits right there. Still, the sight of the Brooklyn bridge right there at Jeff's place will likely move you in a big way.

Since you'll be out this way, if you care to travel 1.5 - 2 hours south to Philadelphia, you're welcome to give my Hornings a listen as well. Since our rooms are so different (brick/hard floor vs. drywall/carpet), the sonic presentation would likely reflect that.

Mapman, I'm not a low volume guy, but understand that's more the rule than the exception. To answer your other question, with the backloaded horns I have been around, yes, some SETs can do more volume than the more familiar push-pull amplifier.

Again, a sort of "coupling" that transcends wpc ratings may come into play. We know it's not electrical impedance in this case, but I don't think the word "impedance" in a different sense of the word misses the mark by far.

Another way to picture it could be the ability to propel the air that exists through the long length of the exponentially expanding horn forcefully enough so that it meaningfully adds to the impulse propelled from the surface of the driver itself. Obviously, I haven't worked it all out, and I've yet to meet someone who can explain it to me. It might be when comparing SET, PP, and OTL amplification, we're dealing with something like the whip versus the club; both of them powerful, but of a profoundly different nature.

My Horning speakers don't do so well with SET 300B, or even PSE, as the dual 12" woofers never get the power they're looking for. I've long wanted to try the 300B based push-pull VAC Renaissance products with them, and see what comes of that.

Rethm speakers do mate in an especially synergistic way with 300B SET amps. The Rethms don't ask the amp to produce the lowest frequencies ala either having no driver that can produce them, or those that do have an onboard solid state amplifier to handle the responsibility.

The 845 and 211 SET amps I've owned all did superbly with backloaded horns. Regardless of specs, no amps rivaled their ability to put power into that type of horn.

My Atma Sphere M60s and a friend's S30 don't couple well with the backloaded horns we've tried with them. Mate the Atmas with the antithesis of that alignment, a true transmission line, and you'll not find better amplification. Also, after hearing the Miyajima OTL with Quad ESL57 in NYC last month, the notorious and wonderful synergy of the electrostatic/OTL topologies comes across clearly.