Sound
OK, so we know that the big Thresholds are built like tanks compared with the go-cart construction of more real-world (pricewise) amplifiers. Two questions must be answered here. Are they among the best amplifiers in the world? (They better…
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Threshold also makes a point of the fact that their STASIS designs maintain a constant (and high) damping factor over the full audio band. Contributing to this is the lack of overall feedback and the elimination of the ubiquitous output inductor (between the final output stage and the output terminal) required in most conventional designs.
Sidebar 1: Specifications
Description: Class-A monoblock power amplifier. Power output: 250Wpc (24dBW) continuous, 500W peak into 8 ohms (resistive or reactive) from 20Hz-20kHz at no more than 0.1% THD. Power bandwidth: DC to 100kHz. Slew rate: 50V/us. Output current capability: 70A continuous (200A peak). Input impedance: 50k ohms unbalanced, 600 ohms balanced. Noise: minimum -100dB, unweighted, against rated output.
Dimensions: 19" W by 8.72" H by 27.75" D. Weight: 130 lbs.
Price: $14,400/pair (1990); no longer available (2007). Approximate number of dealers: 75.
Manufacturer…
Sidebar 2: System
I used the SA/12es in a system consisting of the Oracle Delphi Mk.IV turntable with Oracle 345 arm and Dynavector XX-1L cartridge, Sony CDP-X77ES CD player used as a transport with coaxial link to an Esoteric D-2 D/A converter, Rowland Consonance preamp, and B&W 801 Matrix Series 2 loudspeakers (no LF equalizer used).
Interconnects were AudioQuest Lapis (with the exception of the coaxial CD transport to processor link, which was a garden variety but 75 ohm video cable); loudspeaker cables were AudioQuest Clear Hyperlitz (bi-wire pair). The preamp-to-power-…
Sidebar 3: Measurements
I didn't really expect any surprises in our measurements of the Threshold SA/12e, and none were found. It would, in fact, be hard to imagine better objective performance at the current state of the art. Frequency response was a total non-event—that is, flat within 0.1dB from 20Hz–20kHz (fig.1). Fig.2 shows the Threshold's THD+noise. The three lowest curves indicate (respectively) the low power figures of 1W into 8 ohms, 2W into 4 ohms, and 4W into 2 ohms. The third curve from the top is the 250W into 8 ohm measurement. It edges just barely over the 0.1%…
Stereophile September 1991, Vol.14 No.9, Followup
When John Atkinson asked what I'd like to review for the September issue, I responded immediately that I had some unfinished business to attend to. When I reviewed the Threshold SA/12e monoblock (Vol.13 No.12) and Rowland Model One (Vol.14 No.4) stereo amplifiers, I left a few threads hanging. I'd promised a follow-up comparing the big Thresholds with one of that company's less pricey (though still far from cheap) stereo amplifiers, and I had yet to try a pair of Model Ones bridged as monoblocks. Hence this update.
Associated…
Since he joined Snell Acoustics in the mid-1980s, Kevin Voecks, their chief designer (footnote 1), has been involved in the design or redesign of the entire Snell line, from the minor revision of the Type A/III (incorporation of a new tweeter), to the complete redesign of the Type C (now the CIII). Snell Acoustics is located in Massachusetts, and although Kevin spends a good deal of time there or at the measurement and analysis facilities of the Canadian National Research Council (NRC) in Ottawa, he does a great deal of his conceptual and preliminary design work, as well as his listening, in…
Norton: I guess every designer approaches it differently, but when you originally conceive a new loudspeaker design, where do you generally start your process—how does your conceptual process work?
Voecks: The conceptual process is the part I like—by far—the most, because it's the really creative part, and comes pretty easily. You usually say that you need a speaker in a certain price range—that's usually the direction that you start in—then you start to think about what kind of things could be done for that price. For instance—at $2000 for the CIII, what can we do to make it demonstrably…
Norton: I mentioned, in passing, in a recent article that the listening room is the last frontier of audio. You've done some interesting things in this area. The other day you mentioned to me a new program that Snell is developing to help the customer select the right listening position and the right position for his loudspeakers.
Voecks: That's right. It calculates all the room modes based on its being a rectangular room, then predicts the areas where you will activate room modes and where you won't, and gives options from best to worst for speaker placement. That will be a free service…
When I say that this past—and last—Summer CES in Chicago was dead daddy dead, I'm not talking about fewer high-end exhibits and attendees than ever before. I'm talking I walked in the front door of the Chicago Hilton and almost puked from that smell of dead, mealy meat that hits you in the face and kicks-in the gag reflex. The smell of death you can taste even if you're breathing with your mouth. In most religions, it's a sin to let something that dead just sit there without at least spreading some lye on it to kill the stink. I once cut a man for misadjusting the VTA on my cartridge, and…
Still, coming directly from the ultra-tight, well-defined bass of the NHTs, the C/V's low end betrayed its ported origins by tending toward a slower, more thumping character than the fast and agile sealed NHT woofer. This gave the impression that the bass was lagging somewhat behind the rest of the range during strong rhythmic music, such as Jimmie Vaughan's "Don't Cha Know," off Strange Pleasure (Epic EK 57202). Although the C/V suffers from this to a much lesser extent than the other big Snells, such as the B and B minor, there was still a trace of it in the C/V when compared with the NHT…