From Enjoy The Music August 2009
Also online at http://www.enjoythemusic.com/superioraudio
Reprinted with Permission


Building A Reference System: A Reviewer's Four-Year Odyssey
Part 1 of 3: Strengthening the core with the VTL TL-7.5 Series II preamplifier and Spectron Musician III Mk. II monoblock amplifiers

Review By Wayne Donnelly

Amplification — An Important Interim Step

In setting up the framework for this article, I previously mentioned that I had moved from the VTL MB-750 Reference monoblocks I had in California to the Spectron Musician III Mk II monoblocks that now power my system. There was, however, an interim situation that needs commentary.

Shortly after making the move to Chicago, I decided, finally, to splurge on the amplifiers I had long been fantasizing about: VTL's flagship Siegfried 800-watt monoblocks. Apart from their superb performance, which I had observed in several opportunities, I needed to reduce my dependence on outside help for troubleshooting and repair scenarios. Back in the Bay area, if any problem developed with my VTL amplifiers, I could just wait until the next weekend, when Luke Manley and Beatrice Lam would typically come home from their factory in SoCal. That was important because if, say, I had a tube failure, I couldn't identify the bad because my poor eyesight wouldn't let me find it by visual inspection. Now in a new city, with no established technical or service support, I figured that the Siegfrieds would solve that issue. Their internal diagnostics would instantly identify any bad tube, which could then be quickly replaced by simply lifting the amplifier's hinged lid.

That supposition proved to be correct, although with brand-new amplifiers it took a few months before any tube failures. In the meantime, the sound was glorious. I had expected an improvement, but not a massive one. The MB-750 References had been the best amplifiers I had used until then. But everything the 750s had done well, the Siegfrieds did even better. Bass was both tighter and deeper; imaging precision and soundscape scale and organization were truly remarkable; both ends of the dynamic scale were convincingly rendered; tonal accuracy was exemplary; and the rich, whole harmonics I had always heard from VTL amps were fully in evidence. I really believed I had found my ultimate amplifiers.

But after a few months, the Siegfrieds started going through power tubes at a daunting clip. That phenomenon coincided with my moving to first the Analysis Omega and subsequently the Analysis Amphitryon loudspeakers. This was puzzling at first, because I knew people — including Analysis importer Mike Kallelas — who often drove those speakers with moderately powered (<100W) tube amplifiers with little or no difficulty. After numerous conversations and a lot of experimenting, I realized that although the Analysis speakers could play fine at "normal" playback levels with smaller amplifiers on lighter program material such as pop/jazz vocals or small combos, and especially in more compact listening rooms, they can also absorb tremendous amounts of power playing large-scale symphonic and operatic — or loud rock — music at realistic volume levels in larger rooms. Clearly the total cubic volume of my listening space required a lot of extra watts to fill. I had not thought it would be possible to push the 800-watt Siegfrieds too hard, but the likelihood was that the combination of my listening environment and my penchant for cranking up the sound to feel totally immersed in a great symphony, or opera, or rock concert was proving to be too much for even those big gnarly tube amplifiers.

Support from VTL during all this was outstanding. Several blown KT-88s were replaced under warranty. And on a trip through the Midwest, Luke Manley spent an entire day at my apartment, updating firmware for the amps' diagnostics and running functional tests to try to identify any malfunctions. But we fond no reasons for the problems I was having. Not long after that, when the original Spectron Musician III arrived for a review, I took the opportunity to ship the Siegfrieds back to the factory for a complete checkup. Ultimately, they would never return. My review of the Spectron was sufficiently encouraging that I asked Luke and Bea to find me a buyer for the Siegfrieds. They did so, and I am happy to report that the new owner has not had any of the problems I went through. And even in the face of those problems, I still regard the Siegfrieds as the finest tube amplifiers I have ever lived with

Spectron Era Begins

My review of the original Musician III appeared in March 2006. Looking back now, I recall how surprised I was by its overall excellence. I had previously heard a couple of decent-sounding digital amplifiers, but my feelings going in were still that I preferred tube amplification to solid-state. Moreover, I had heard several non-digital transistor amplifiers that were better, to my ears, than any digital amps I had tried up to that point.

But it didn't take long to realize that those long-held suppositions — after all, I had been listening mostly to big tube amps since 1995 — simply couldn't hold up under what I was hearing from the Musician III. Not everything was a surprise. That the Spectron's bass response was quicker, deeper and tighter than the Siegfrieds was expectable from past experience, but the tonal purity and flawless pitch definition of the low frequencies were the most refined I had heard from any amplifier — even marques such as Levinson and Krell that were widely celebrated for their bass "slam."

I also expected, and heard, the Spectron's extraordinary speed. Leading edges of transients were impressively clean and precise, even very low-level ones. And speaking of low-level program content, the Musician III was also the quietest amplifier I had lived with. Even with the volume control of the VTL 7.5 cranked up to potentially dangerous levels, the CD input with no music playing was dead quiet, and the phono input very nearly so. Spatial resolution was first-rate as well. Images of individual instruments and voices were precisely located, with above-average dimensionality — although in this area performance still fell slightly short of the Siegfrieds.

What surprised me about this amplifier was the absence of negative characteristics that I was accustomed to associating with transistor amplifiers in general and digital amplifiers in particular. I heard no graininess, either in the midrange or — surprisingly — in the high frequencies. Voices and instruments emerged sounding fresh and whole, with that "in the room" quality we are always looking for. Also notable was a more complete rendering of harmonics, which gave every musical genre weight and substance that came very near what the Siegfrieds had been able to deliver. Overall, while in these areas the Siegfrieds were still champs in my experience, the Musician III came so close that, given its areas of superiority and its far lower cost, I made the momentous (for me) decision to leap from tube amplification into the brave new world of high-performance digital.

Making A Great Amp Better

Spectron did not rest on its laurels. Designer John Ulrick, unlike some digital engineers I have known who still parrot the "perfect sound forever" digital bias, is very aware that many factors come into play in making a great amplifier, and he has been refining the design and improving parts quality in key areas. Later in 2006, he made a major change to the linear power supply of the Musician III, replacing the original two large electrolytic storage capacitors with 100 smaller, faster capacitors. I sent my amplifier in for the upgrade, and the improvement was quite impressive. Without naming every detail, I can say that Spectron has quietly continued to improve parts quality in circuit components, internal wiring and connectors.

In addition, a couple of optional upgrades can further refine the amplifier's sound. I admit to suggesting one of those, adding Jack Bybee's 'Super Effect' Internal A.C. Bullets, to the power supply — which proved a most desirable upgrade. The new Bybee Wire company that Jack Bybee has licensed to use his technology offers a power cable incorporating the same devices, which retails for more than $3,000. The Bybee upgrade to to the power supply is the equivalent of adding such a cable to the amplifier, and gains in overall quietness, resolution of low-level detail, micro dynamics and spatial precision are quite palpable. Another option, putting the sonically excellent V-Caps in the power supply, has a slightly more subtle effect, but contributes materially to the sense of ease and relaxation in the amplifier's sonic presentation.

The cumulative results of numerous upgrades had by last year justified a new model designation: the Musician III Series II. I strongly recommend that the interested reader go to the detailed technical description of the Musician III Series II on Spectron's web site. There is also information and pricing for upgrades to bring older versions of the amplifier to or near Mk II performance.

Around the middle of 2008 I began hearing a lot of scuttlebutt about deploying Musician IIIs as monoblocks. Word was that as monoblocks the Spectrons were not just much more powerful, but also sounded better than a single stereo amplifier. I had been able to play music at satisfyingly unsafe levels even with one amplifier, but I was intrigued by what I was hearing about the monoblocks, so I decided t check out that configuration. After all, even a fully loaded pair of Spectrons total a bit over $20,000 — not exactly chicken feed, but a fraction of the Siegfrieds' $50K sticker price — and a bargain, in my opinion for what would be both the most powerful home amplifiers I have found.

Listening To The Musician III Monoblocks

Bridging these amplifiers for monoblock operation is very simple. With the configuration I used, there is no need to make any internal changes. One simply connects either RCA or XLR interconnects into both channels of each amplifier, sets one of each amp's two back-panel phase switches to NORMAL and the other to INVERT, and then connects the speaker cables across the + contacts of the left and right channel speaker terminals. This procedure was easy for me because the VTL TL-7.5 provides two RCA and two XLR MAIN OUT jacks for each channel

But many preamplifiers have only single MAIN OUT jacks for each channel. Spectron offers different options. If the customer already has a stereo amp and buys another, RCA or XLR Y-connectors may be used at the amplifier to enable one interconnect to serve both channels. A more elegant solution, especially if two amplifiers are ordered at once, is to have Spectron wire each amplifier internally for bridge-mode operation. That option has the additional benefit of requiring only one interconnect per amplifier.

I set up the monoblocks just before going away for a week, so I was able to leave the system playing music softly for the entire time I was away — so that when I returned, basic burn-in had been accomplished and I could get right down to serious listening. Among other things, I brought out the same recordings discussed previously in the context of the VTL TL 7.5.

Earlier on, I had recognized a number of differences between the Siegfrieds and the stereo Musician III, but listening through the Spectron monoblocks has been revelatory. The Dorati Firebird now has full harmonic richness equaling the all-VTL rig, along with a dynamic range that now extends beyond what the all-tube configuration could produce, and a combination of bass impact and finesse that is wholly new to me. On Munch's Berlioz, there is a new, more guttural rasp to the low strings, as well as even sharper leading edge transients from brass and percussion. Same story with the Bernstein CD.

Those results are extremely satisfying, but hardly a surprise given what I had heard through the intermediate stages of this process. What did surprise me, on all three of those great recordings, were the improvements in spatial presentation. The stereo Spectron had given me precisely located images within the soundscape. With the monoblocks those images retain their precise lateral organization, but the images are more three-dimensional than with the stereo Spectron, and equal to what was a major strength of the Siegfrieds. Even more surprising, and a challenge to describe adequately, the listening experience is now simply more relaxing and pleasurable than at any time in the past.

That pervasive sense of ease, even at playback levels that would drive fainter hearts from the room, is achieved by Spectron's remarkable power supply concept. In stereo, the Musician III Mk II substantial toroidal transformer provides ± 120 V — roughly double the voltage of a typical high-powered stereo amplifier. In bridged mode that voltage doubles to ± 240 V. If called upon to do so, a bridged Musician III Mk II can produce a 7000-watt peak for 500 msec. I know of no other audio amplifier that can equal the headroom of a bridged Musician III Mk II, whether measured in voltage, wattage or peak duration. In music listening terms, this means that these amplifiers are cruising comfortably at playback volumes that would make most "big" amplifiers gas out and clip audibly.

My Personal Paradigm Shift

I've been consistently a toob man for some 15 years. I have heard very good transistor amplifiers and have praised them in reviews, but I never found one that tempted me away from the pleasures of glowing glass. And digital amps? They used to be a no-brainer "forget about it!" I still love tubes, of course, and they loom large in my system. But I know now that it's time to rethink some of my traditional audiophile prejudices.

Like many audiophiles of "a certain age," for years I regarded "digital" as a veiled swear word. I recall that back in the 1980s, having heard the early hype on CDs and "perfect sound forever," I borrowed the original hot-stuff Meridien CD player and a handful of discs from an engineer friend and stuck my toe gingerly into the murky waters of the CD revolution — and quickly yanked it back out! Whether Springsteen or Stravinsky, the damned things were just unlistenable. Five minutes at a time were as long as I could stand. I didn't break down and buy any digital playback equipment for several more years, until new releases I needed to hear were no longer available on LP. And even though digital playback has improved cosmically since then, I still get the greatest pleasure playing LPs.

But these Spectron monoblocks are a whole different matter. They give me the glare-free sweetness, the harmonic completeness and the spatial verisimilitude of the best tube amplifiers, with a new and exciting degree of transient speed and essentially unlimited dynamic impact. No, they don't sound like the Siegfrieds. There is indeed a special quality to the sound of tubes — a kind of creamy sweetness in the harmonic presentation, that the Spectrons do not duplicate. It is easy to understand the appeal of that tube sound; it has had a grip on me for years. But what the Spectrons do is, to my mind, ultimately even more impressive. The Musician III Mk II monoblocks have a crystalline purity in the reproduction of every voice and instrument that sounds more to me like the essence of live, unamplified music — which I attend, on average, more than once a week year-round— than any other amplifiers — at any cost, based on any technology — that I have ever heard. A strong core indeed!