Fantasy comparison: Rotel RMB-1077 vs Parasound Halo A21
Al Sekela -- Sat, 02/10/2007 - 15:17
Barry Willis says this about the Rotel in TAS 170:
"Audio traditionalists may not be ready to accept this, but to my ears the Rotel RMB-1077 is one Class D amp that can hold its ground in a showdown against any tube or Class AB solid-state amp."
Jonathan Valin says this in his review of the A 21 in TAS 168:
"What the A 21 is is a very fine amplifier at an exceptionally fair price - more lifelike, I think, than much of its more expensive Class D competition."
Whether or not Mr. Willis' comment was directed to Mr. Valin, I would love to know what these gentlemen would say about a direct comparison of the two amplifiers.
I've heard the Parasound JC-1 monoblocks (solid-state Class A/B), the Wolcott Presence monoblocks (tube Class A/B), and the Gilmore Raptor monoblocks (Class D) on the same pair of SoundLab M-1 speakers, and with same sources, etc. The Parasound amps were harsh and mechanical, the Wolcotts smoother but bass-shy, and the Raptors the most lifelike.
Unless the A 21 is considerably more refined than its older brothers, or the Rotel is much improved over the selection of Class D amps reviewed in TAS 166, the striking difference in these comments is either due to differences in the individual reviewers' tastes or some other cause.
If we really are at the level of equipment refinement where individual taste is a more important cause of variation in satisfaction than any conceivable difference in amplifier behavior, then there is not much more to be gained by reading equipment reviews. I don't think this is true, so I would like to see TAS focus on resolving the nagging doubts about Class D treble performance raised in TAS 166. A direct comparison of the Rotel and Parasound amps would be one way to start.
I think there are two other factors (beyond personal taste and the level of refinement of current products) to be considered in understanding why reviewers may come to different views of the same piece of equipment (not the case in the reviews mentioned by Al, except by inference, but fundamentally this is behind his question).
First, while two products may not be even close to perfect, their overall performance levels may be similar. That means differences between them may be subtle. Second, reviewers almost always review equipment under different conditions. That is, even if the same equipment is used, the rooms are different. And, in most cases, the equipment is different, too. If we start with premise #1 (somewhat similar equipment) and then apply this similar equipment under premise #2 (different equipment in different rooms) it isn't hard to understand why two reviewers would come to different sweeping views (good/bad, or I really liked it/I wasn't in love with it). As a result, reviewers put a lot of work into more detailed descriptions of how equipment sounds. Therefore, reading at the level of sweeping generalizations ("can hold its ground against any tube or class A/B solid-state amp") can easily be misinterpreted. But, given the other detail presented, like Al, I would hardly say the reviews aren't useful when read as intended.
I've heard the JC-1s with the M-1s on several occasions—Sound Lab has chosen to show with the Parasound amplifiers (and Curl's "Blowtorch" preamp) at the last few CESes and I have a friend who uses them with the M-1s—and without intending to dispute what Sekela heard and without claiming that the Parasounds are anything more than what they are (very good Class AB solid-state amplifiers at a reasonable price), the JC-1s have never sounded unduly "harsh" to me with the M-1s or, apparently, to Dr. West (Sound Lab's president and the illustrious designer of all Sound Lab speakers). It is my understanding that Sound Lab uses the JC-1s at trade shows because they control these difficult-to-drive speakers well (for which, see below), are reliable and headache-free, and sound good (or good enough under show conditions to make for impressive demos). I know that they are not Dr. West's first choices in amplification, but they are a respectable second.
Since I own a pair of M-1s and reviewed them many years ago in Fi, I am very familiar with the kind of loops these 'stats can put power amps through. (They would not be my first pick for testing amps—indeed, they would be close to my last.) Depending on the version, the M-1s can be a very difficult load, ranging in impedance from the high double-digits in the bass to the low single-digits in the treble. In my experience, solid-state tends to handle these impedance spitballs better than tubes (OTL or AB), showing markedly better control at the frequency extremes (particularly in the bass). However, you can trade off a good deal of midband voluptuousness and upper-frequency air and delicacy in the bargain. (The M-1s, all Sound Labs, are among the most gorgeous-sounding loudspeakers money can buy.)
For the money, the JC-1s have always struck me as a fair deal. No, they aren't as rich and lovely as Wolcotts with the M-1s. They are leaner and darker and considerably less airy, delicate, and open (as per my review of the A 21s) than the best amplification.
Sekela reports that the Gilmore Raptors sounded better than the Wolcotts and the Parasounds with the M-1s (!). I would, of course, have to hear that to believe it, but it could be that the Class D amp’s high damping factor in the bass and relative softness in the treble played to the M-1s weaknesses and strengths. I remember trying the Krell FPB650s with the M-1s—amps that did, indeed, sound lifeless and “mechanical” with conventional speakers. With the M-1s, they were a gorgeous match. It was almost as if they needed a tough load to sound their best. Perhaps, the Gilmores are another magical combo with M-1s.
Al Sekela wrote:
If we really are at the level of equipment refinement where individual taste is a more important cause of variation in satisfaction than any conceivable difference in amplifier behavior, then there is not much more to be gained by reading equipment reviews. I don't think this is true,quote]
Al Sekela-
One of the underlying currents to a lot of the internet hifi chatter flows around the idea that reviewers as a group are ultra-finicky, elitist, and miopic when reviewing equipment. My personal take on the members of the fellowship is that the vast majority for whom a wide range of music and equipment experience inform their views tend to agree on what is good, very good, and even excellent. In other words, sit the top ten audio reviewers from around the globe (a group that would include some of the gents on this forum btw) down in front of an all-MBL OR all-Linn system, and you would have a consensus on the strengths and weaknesses of each bit of kit.
It can never be under-appreciated how important proper set-up is to achieving what good hifi is capable of showing. Component interaction is the other devil in the details. ( One of the skills great reviewers have is an instinct to know how to get the best from any given product.) This is why I think we'll see more complete system reviewing by the press in the future as the demise of a skilled dealership network begins to leave a big, fat hole out there.
Thanks for the interesting topic Al.
best,
Scott
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