VTL MB300 & MB450 Signature monoblock amplifiers Page 3
So, what does the 300 sound like? Not much. It seems to have very little sound of its own, which is (or should be) what we're all looking for in an amplifier, so its sound is very hard to describe. Adjectives like "sweet" and "open" and "detailed" and "solid" lose a lot of their meaning when applied to sound that is just as musically right as that from the VTLs.
I've explained before in these pages why it is impossible to determine how neutral or uncolored a power amplifier is, so I won't repeat myself here. Suffice it to say that bypass or Hafler-style cancellation tests have failed to date to reflect how amplifiers actually sound under real-world operating conditions, and that the best approach continues to be informally statistical, based on the "average" spectral balance of the majority of cost-no-object designs. For example, the best solid-state amplifiers never sound quite as forward as the best tube designs, so it seems reasonable to assume that a "neutral" midrange would fall somewhere between them. The VTL 300's midrange does that.
I'm not saying the VTL 300 is perfect, just that I haven't yet found anything the matter with it. (More extended listening may change that.) I can say, though, that these amps are entirely free from texturing—grain, dryness—and that they come as close to providing a perfectly clear window on the original sounds as any amplifiers I have ever used. I have yet to hear anything in the sound that I could attribute to a characteristic of the amplifier; it simply does not call any attention to itself at all, except when driven into overload, which is not all that easy to do. (Overloaded, the sound merely becomes slightly fuzzy. There is no hash or crud. The likelihood of damaging tweeters with these amps is probably very low.)
Readers may recall my rhapsodizing over the exquisitely realistic high end from VTL's little 75/75W stereo amplifier, while complaining, perhaps unfairly, about its deficiency of muscle. I fully expected the 300-watters to have the muscle that the 75/75 lacked, but long experience had taught me to expect degraded high-end performance from higher-powered versions of superb low-powered amps. There isn't. In fact, as well as memory serves me (and my aural memory is legendary), the 300s sound almost exactly like the 75/75 except for their immensely increased maximum-volume capability and an even better low end. That same HF magic is still there, without the 75/75's offsetting weaknesses in the mids. I would not have believed it possible that any high-powered amplifier could have a sweeter high end than the Audio Research M-300 without giving up detail, but the VTL 300 has accomplished that seemingly impossible goal. Its highs are sweet and natural enough to allow me to operate the Sound Labs with their HF-limiting pots wide open.
The 300's high-end ease does not seem related to HF content, but to its harmonic rightness. For this reason, the amp does not sound duller-than-life through dynamic systems, as do amps which achieve their apparent HF sweetness by softening the upper overtone range. This is one of only three amplifiers I have found which are equally suited for use with electrostatics and dynamic speaker systems. (The other two were the Audio Research M-300s and VTL's 75/75.)
If you have been reading my reports in past issues, you may have noticed (footnote 2) that one of my pet peeves is the seeming inability to reproduce convincingly the true weight and authority of an orchestra's large brass instruments. The 300s do this as well as any amplifier I can recall having heard (the others were tube units too). Whether this is the result of a euphonic coloration or superior tonal accuracy is moot, but I really don't care which it is. All I care about is that, given a speaker system with the capability, these can approximate the size and power of a full symphony orchestra like few power amps I have heard.
Ah, but the low end: That's where all tubed amplifiers fall flat on their faces, right? Right. Even the ARC M-300, as incredibly good as it is, is a bit rotund through the midbass and sparse through the deep bass. The 300 isn't either of these things. It must be said that some solid-state amplifiers, like the big Krells and Thresholds, have a shade more authority and punch at the extreme low end than the 300, but this is, nonetheless, the first all-tube amplifier I have heard whose low end can give those solid-state amplifiers a run for their money. And it isn't even direct-coupled! Clearly, DC coupling would not be possible through the output transformer anyway, but there are also two interstage coupling capacitors in the signal path, albeit of what looks like a high-quality polycarbonate type. It is probable that the 300's low end would be even deeper and more gutsy if the voltage amp stages were direct-coupled, but I must say I find that difficult to imagine. The 300 does not have the LF leanness I have heard from most solid-state amplifiers which were not direct-coupled throughout. Its low end is almost impossible to fault!
Soundstage reproduction from these is truly awesome. They throw an immensely wide and convincing spatial presentation, accounting in large measure, I now believe, for the remarkable spatiality I got during my tests of the Infinity IRS Beta loudspeakers. The loudspeakers seem almost incidental to the sound; you can see them, but the sounds you hear seem completely detached from them, and the imaging specificity is so good that individual voices take on an almost-palpable reality of their own. Depth rendition, too, is very convincing, from proscenium to rear-stage shell, with the rows of instruments clearly ranked one behind another, and each surrounded by a sharp-edged outline separating it from the surrounding space. You almost get the feeling you should be able to see the instruments.
I am tempted to assert that there is no longer any excuse for buying Audio Research M-300s, but I can't because I am not sure it is true. Granted, the VTLs are somewhat better-sounding amplifiers at a hair less than half the price, and granted that our own experience with Audio Research products has not indicated a very high degree of reliability, but it still makes sense to buy from an established and enduring manufacturer rather than from a relative newcomer that may or may not still be around a year from the purchase date. We know little about VTL's product reliability record, and while I have heard fewer outside reports about VTL failures than I have about ARC failures, this could be only because Audio Research sells a lot more amplifiers than VTL.
There are signs, though, that VTL's amps may be very reliable. The manufacturer offers a lifetime warranty on them, transferable from owner to owner, which is very unusual and is certainly indicative of great confidence in the product. (Tubes are warranted for 6 months, but only if you use one of VTL's own preamps.) And the relatively cool operation of the 300s is certainly a longevity plus-factor, as it is well known that heat impairs both the reliability and the longevity of tubes. Ultimately, though, only time and an earned reputation can show that VTL's amps are as reliable as the manufacturer says they are. On the other hand, we continue to hear disturbing reports about VTL's customer relations: slow turnaround on repairs, and customer phone calls answered by a machine, with no callbacks forthcoming. Nor is the fact that Stereophile has had some difficulties contacting them on occasion reassuring. My advice would be to make sure your dealer has a decent service department before buying a pair of 300s, just in case.
As for now, though, there is no doubt in my mind that the VTL Monoblock 300s are the best power amplifiers I have heard, by a substantial margin and at a remarkably low price for that level of performance. Expressed reservations notwithstanding, I would recommend them to anyone who can afford them. Buy them, live with them, and just forget about power amplifiers until someone comes up with a major design breakthrough that will render these (and all else) immediately obsolete. But don't hold your breath until that happens.—J. Gordon Holt
Footnote 2 Or have even by now grown inured to.—J. Gordon Holt