The other salient feature of the M100A is that it's single-ended, "a configuration which is seldom used in transistor amplifiers." TdP goes on to explain…
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A distinguishing feature of the M100A is its transformer coupling at the output. (The only other solid-state amps I'm aware of that use this topology are some of the McIntoshes.) The documentation explains that this "offers advantages to the designer who can produce suitably high-quality transformers. Tim de Paravicini, probably the leading authority on audioband transformers, is such a designer." It's good to believe in oneself, no?
Electricity? I wondered. Poor Man's Balanced Electrical Running (two different phases of positive, footnote 1) was noisy on the M100As, with boatloads of RFI. Running both amps into one Cardas star-wired power extender with Synergistic Research Designer's Reference Master Couplers2 power cords into one of our isolated 30-amp sockets quieted things down enormously. Curious.
But however the electrical supply was configured, no matter which power cord I tried, the M100As still sounded lean and underpowered. So I began to play with preamps. I got the best results (but wildly different…
In due course, the report came back from Mr. Meinwald: "Jonathan, the amps were victims of excessive handling." Oh, the bad jokes that beckon! Rowan Atkinson muzzled! Meinwald gamely ticked off the lurid details: "Well, these were the first production pair, and they'd been all over Germany, then back to the UK. There converted to 110V operation and shipped to me in California. I took them to and from Las Vegas CES, then, following a short break, it was off to New York for Home Entertainment 2001 in May, where they worked flawlessly."
The plan had been to schlep them from HE2001 down to…
Sidebar 1: Specifications
Description: Single-ended, class-A, solid-state MOSFET monoblock amplifier with transformer-coupled output, single-ended and balanced inputs and passthrough outputs. Output power: 100W maximum (28V RMS on 8 ohm terminal) (20dBW). Frequency response (at 1W output): 3Hz–40kHz, –3dB. Power bandwidth: 20Hz–40kHz, –3dB. Damping factor: 8. Input impedance: 47k ohms. Sensitivity: 1V for full output. Residual noise (volume at minimum): 0.5mV. Maximum distortion: 2% at full power.
Dimensions: 23" H by 10" W by 20" D. Weight: 154 lbs each.
Serial numbers of units…
Sidebar 2: Associated Equipment
Analog source: Forsell Air Force One turntable/tonearm, van den Hul Grasshopper IV GLA cartridge.
Digital sources: Accuphase DP-100 and DC-101 SACD/CD transport upsampling DAC, Linn Sondek CD12 CD player, dCS Purcell D/D converter, dCS Elgar Plus DAC.
Preamplifiers: Lamm L2, Mark Levinson No.32 Reference, Conrad-Johnson 17LS line stage, C-J Premier 15 phono stage.
Power amplifiers: Cary CAD-280 V12, Krell FPB 350MC monoblocks, Forsell Statement.
Loudspeakers: JMlab Utopia.
Cables: Digital: XLO The Limited RCA and AES/EBU. Interconnect:…
Sidebar 3: Measurements
The first round of measurements were performed on the sample that had not developed audible distortion. Noting that the M100A is described as operating in class-A, my usual practice before measuring an amplifier is to run it at one-third power into 8 ohms for one hour. This severely stresses a design with a class-B output stage, as it results in the maximum heat being dissipated in the output transistors. My first test for any amplifier is therefore to quickly check its clipping power at 1kHz (defined as 1% THD+noise) with my Audio Precision System One.
I…
Now that Stereophile's reporting on the 1985 Summer Consumer Electronics Show has ended (I hope!), I would like to express strong dissent with its style and content. In fact, I believe that most of it should never have appeared in print.
I don't attach any cosmic significance to audio reviewing. It's supposed to be fun, not the source of ultimate truth. I do, however, believe that it must be responsible to both the audiophile and the industry. Subjective reviewing is one thing, but shooting from the hip is quite another. Praising or damning the sound and technology of products on the…
J. Gordon Holt Responds:
Sorry Tony, I just can't agree.
Sure, CES is just a showcase from which dealers choose the lines they'll carry, and it's common knowledge that most dealers put sound quality at the bottom of their priority list, well below such mundanities as mark-up, manufacturer promotion, and the glitziness of the product's hype. And if Stereophile was a trade mag, aimed at dealers, that's the way we would approach our show reports.
But Stereophile isn't a trade magazine. It's a consumer publication, for people who care greatly about sound quality, and it is…
Larry Archibald abuts:
I'm of two minds in this debate, because there seem to be significant defects in both arguments presented above. I feel that Consumer Electronics Shows are an excellent place to encounter interesting products, products that are good prospects for reviews. And sound quality is one way to decide which manufacturers to interview, which products to pursue. The CES also provides a unique opportunity to get technical clues from the designers whose products sound good; given the plethora of exhibitors, there's a tendency not to check out the rooms that sound bad. So I…
Although inclined to mood swings bordering on the manic-depressive, I am generally a very patient, tolerant person, willing to accept and overlook the foibles of those less perfect than myself. But even my incredible equanimity has its limits, beyond which the milk of my human kindness curdles, becoming as lumpy as last month's yogurt.
Perhaps I have just grown tired of certain kinds of mindless idiocy. Perhaps I am, in fact, growing shorter in tolerance as I grow longer-sighted. But if, perchance, you should engage me in casual conversation or intense technical or philosophical…