A MAJOR FAULT COMMON to MOST AMPLIFIERS: Where's The Body?

-The Good, The Baad, and The Ugly - (3 amps in my system)

by W.A.J.

Most popular POWER-AMPLIFIERS should be locked-up in a secure room with the keys thrown away - solid-state especially. Their overall performance is that deplorable, in my opinion, but if one is willing to endure average performance then I suppose they’re fine. Limited aspects of their performance can be very good though - bass for sub-woofers, for example – and may be sensibly utilized within such a limited context. Furthermore, if one is content with an average system, then a high-quality amp would be unwarranted since the full quality of this amp would be obscured by the mediocre components in the chain.

I currently use three power-amps; UREI 6150 ‘full-range’, Crown Micro-Tech 1200 mid-bass, and Sherwood AM 7040 deep-bass. Overall, the Crown and Sherwood are nothing special, they should probably be locked-up too, apart from the fact that they are OK to very good, respectively, within their limited scope in this system. The UREI, however, is one of the three best power-amps I’ve ever used. The others were a Quad 303, and a custom-built ('Tho-mas') tube power-amp, of which the Tho-mas was better. I would need to compare all three in this current system to determine the ultimate winner, but I can say the UREI provides a level of performance never matched by those two in a top-quality system at the time.

THE UGLY: Apart from its bass, the Sherwood is firmly ensconced in the realms of mediocrity. And it shouldn’t be overly proud of its achievements since many of its mediocre brethren have similarly passable to good bass. In fact, its overall performance epitomizes that of the majority, as I've experienced, including many well reputed high-end amps out there, so I’ll describe it.

Though its treble is nothing to write home about, I’ll concentrate on the mid-range since that is where most of my major problems lie with the majority of amps I’ve encountered. Alleged 20-20 frequency-response notwithstanding, the Sherwood and most others chop off lower-mid-range sounds (from around 500 to somewhere about 200hz, in my estimation). The sound is therefore thin, lower mid-range BODY is absent, so the picture presented is incomplete. (The similarities with many high-end amps end there). And if that were not enough, what’s left of the Sherwood's butchered mid-range is un-natural, hard, edgy, electronic-sounding, metallic and totally false. This amp's mid-range (like that of many) is the sonic equivalent of 'ugly'. I’ll stop here.

THE BAAD: The Crown (from above deep-bass up) could be called the best of a bad lot. It boggles the mind, though, as to how Stereophile mag could have been using its sibling, the Macro-Reference, as a reference for some of their reviews, but there you have it. (They definitely share a similar sound, as does a Macro-Tech 1200 I once owned. In fact the Micro-Tech, Macro-Tech, and Macro-Reference all share similar sonic characteristics, and possibly a similar circuit).

The Crown displays the same lower mid-range deficiencies of most amps, and, for me, that alone disqualifies it from full-range use in any high-end system that I would want to own. The rest of the mid-range, though, is outstanding; smooth, crisp, clear, accurate, even if slightly electronic (‘transistory’) sounding. This amp is also slightly more dynamic than my favorite. The treble is also smooth, crisp, clear, and somewhat prominent. However, another intolerably un-natural trait is this amps exaggeration of sibilants (that ‘sssss’ sound in ssspeech and sssong). Bass is powerful, tight, and totally awesome. It’s also totally un-natural, in my opinion – especially deep-bass (ie; overly tight and hard sounding, devoid of detail, and seemingly prematurely curtailed).

Nevertheless, this amp can be absolutely, crushingly, devastatingly impressive in a less accurate system. For disco/house/techno, etc., it's a 'baad mama-jamma' – hell, I once bought two, in quick succession, when I didn’t know better. If you're a DJ, or you own/operate a mobile sound-system, as I once did, or even if you just love the disco-sound, then you owe it to yourself to check out the Crown. (The UREI also shares commercial roots, btw). Notwithstanding Peaveys and QSC's, etc.,the Crown, any Crown, is among the best of that lot, most others sound awful in comparison (with mids like the Sherwood's, and worse) believe me, I've been there.

The Micro-Tech's hyped treble is super-sweet, the mids are crystal-clear, and mid-bass, also hyped, is CANTANKEROUS - it kicks like a demented mule. In the commercial field, where hype is the order of the day, the Crown is king, with a name that's fitting - in my way of thinking. It's just that, in the field of high-end audio, hype just doesn't cut it (no, that's not actually true, and it does sound 'better' than some 'high-end amps' - but hype should really have no place in high-end). For me, an exaggerated treble and mid-bass combined with a lack of lower-mids and authentic deep-bass just cannot be accommodated in a system designed for accuracy and realism.

The Sherwood, on the other hand, conveys bass that is much more natural; deeper, smoother, rounder and much more textural – affording greater insight into the components of the sound, even in the mid-bass region. So, for this reason, and the fact that the Crown’s fan is annoying, I now mostly use one side of the Sherwood for mid-bass, and the other side for the low-end. Stereo bass will be restored when I replace that 'Crown of thorns' (that's not fair - but I couldn't resist) with perhaps another UREI, hopefully extending some of its lower-mid articulation to the mid-bass region.

THE GOOD: Ah, yes, the UREI – the love of my life so far as amps are concerned. What can I say about the UREI? I’m sure there must be better amps out there – Audio Research Reference Series, Lamm, Coincident, McCormack, Clayton – but I haven’t found one yet to tear me away from this little unheralded over-achiever. One of my favorites, the Atma-Sphere M-60, has subsequently been reported to have a sonic short-coming I’m not prepared to endure (another case of the missing body - re; 10Audio web-zine), and this is in an area where the UREI is strongest.

Other candidates may also have limitations I’m not prepared to tolerate, so for now I’m sticking with my champion. I’ve passed up chances to replace it with Aragon, Bryston, McIntosh and an Audio-Research (early VT100) with no regrets since none of these were really significantly superior, overall, to the UREI with its low-feedback circuitry (the secret to its quality, I believe). Apart from amps equivalent to those in my first list, I believe the only significant increase in quality, at reasonable cost, could come from an OTL or S.E.T. tube-amp design, or a vintage giant killer such as a modified Ampex or Stromberg-Carlson. I’ll keep them all in mind, but for now I’m content.

One could say the UREI is remarkably unremarkable - a supreme complement for any amplifier – no aspect of its sound jumps out to say, ‘Hey, look at me’, and nothing is missing. The sound is neutral and absolutely NATURAL. They say it’s solid-state (transistorized) but I'd swear there must be a tube or two in there somewhere as it's capable of sounding more tube-like than some tube-amps I’ve known. But the UREI’s greatest achievement is in the area where most other amps fall flat on their back-sides – in the lower mid-range. It facilitates the reproduction of all the detail in this area that those others don’t even acknowledge – the low-level sounds, the fade of notes, the weight and resonance of instruments - it allows a system to supply that elusive LOWER MID-RANGE BODY in spades. That, along with its other attributes, puts it in a class above the rest, as far as I’m concerned. Of course, it's good!

Three cheers for the champ: Hip, hip - UREI, etc., etc.

And to think I’d literally given this amp away to a friend who turned around and sold it to the friend who had originally sold it to me in the first place. After nabbing it again on an extended loan, I practically begged for it to be sold back to me as my system had improved enough (with KLH speakers - yes, absolutely - and a new ARC pre-amp) for me to finally appreciate how much better it was than those (like the Crown, for instance) that seemed to equal it when my system was less revealing. I won’t make that mistake again, be assured.

I'm sure there's a lesson in here somewhere!

Copyright 2010