Cary Audio Design SLM-100 monoblock power amplifier
I should mention that I reacted to the single-ended triode phenomenon with great skepticism. My negative biases were twofold: 1) I have little interest in products with limited applicability to the marketplacethe low-powered nature of most of these beasts results in matching problems with many speakers; and 2) I have a natural bias against very expensive products. As I tend to compare amplifiers on a price-per-watt basis, single-ended triodes come out worst.
My first experience with this genre of "hornblowers" began with an invitation by neighbor Andy Benjamin, a long-time contributor to The Abso!ute Sound, to hear his new Cary CAD-805 monoblocks. I trundled over and heard these sexy, glowing beasts perform incredible magic on his MartinLogan CLS electrostatics. With a seductive midrange and uncanny stage presentation, the combo was one of the finest systems I'd ever heard.
My reaction to this experience was not to join in the single-ended triode frenzy, but to run in the opposite direction. "These Cary guys are pretty clever. I wonder if they make any normal amps," I thought. You know, push-pull stuff with 6550s or EL34s that can kick out at least 100 per.
A quick look at the Cary catalog, and Aha! I see the SLM-100 monoblock! A hundred push-pull watts into 4 ohms (113 into 8) for only $3495 retail! It would be a kick to compare a pair of Carys to my beloved reference amplifier of six years, the similarly priced (and tubed) Audio Research Classic 60.
When the Carys arrived, I was stunned by their beauty (they sent me the $500-extra chrome-plated jobs). Moreover, I was impressed that the high standards of parts and construction quality featured in their more expensive wares seem to have not been compromised in the SLM-100. The amp is outfitted with 1% metal-film resistors, polypropylene coupling capacitors, and all wiring is point-to-point.
The design features a pair of 6SL7 tubes as the input, pre-driver, and phase-inverter stages, with the input stage buffered and direct-coupled to the phase-inverter. The amp uses Svetlana KT99A (6550) output tubes in a push-pull configuration, and employs a custom-designed Ultralinear output transformer. In the dark, the sight of the SLM-100's row of output-tube filaments gleaming off of the chrome was stunning. (A friend refers to them as "the apostles' tongues of fire.")
The first thing that struck me about this amplifier was its glorious tubelike midrange. Vocals, whether Janis Ian (Breaking Silence, Morgan Creek 2929-20083-2), José Carreras (Misa Criolla, Philips 420 555-2), or Mighty Sam McClain (AudioQuest AQ1015), the seductive reproduction of well-recorded voices melted me down into a puddle. Yes, there was a bit of euphonic tube sweetening (which also had a somewhat forgiving effect on massed strings on dryish orchestral recordings and added a touch of Log Cabin syrup to brass), but I didn't care. I just wanted to close my eyes, sway, and sing along.
Adding to the realism of the Carys' vocal reproduction was the dimensional body accorded to vocals and instruments in their wide and deep soundstage presentation. This, combined with excellent detail resolution, ambience retrieval, and image specificity, makes these amps well-suited for those who cherish well-recorded orchestral music. Simon Rattle's reading of Stravinsky's Pulcinella (EMI HMV ASD 3604, and one of the finest EMIs ever recorded), as well as Previn's recording of Messiaen's Turangalîla Symphony (EMI SLS 5117), delivered a realistic replication of musicians performing in real space. And when I threw a highly dynamic classical blockbuster at the Carys, such as Crumb's Makrokosmos III (Nonesuch 71311), I found they could deliver staggering dynamic contrasts, from ppp to fffthe widest dynamic contrasts, in fact, I've heard in any of my systems.