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
Click here to e-mail reviewer.

  To quote the great philosopher Jerry Garcia: "What a long strange trip it's been." Four years and 2000 miles have indeed been quite an odyssey, but one that has culminated in a soul-stirring audio system, ensconced in a superb listening room, in the heart of a stimulating and culturally diverse city that offers many opportunities to encounter great live music of every genre. (For an overview of my current system and listening environment, see my reviewer's bio.)

How Did We Get Here?
This short narrative is included to provide a context for the equipment evaluations that will fill these three installments.

In June 2005, after 18 years in California — initially in Orange County, then 16 years in the San Francisco Bay area's Silicon Valley — I moved back to Chicago. I had spent most of the 1970s there, doing Ph.D. work at Northwestern University, teaching there and at the University of Illinois/Chicago, and dipping my toe into the audio business as a salesman for Audio Consultants, one of the great retailers in the industry — where I contracted a serious case of audiophilia aeterna. The move back to Chicago was prompted largely by my worsening eyesight, which had deteriorated to legal blindness in just one eye. That meant driving a car and many other normal daily activities were no longer possible. In case you haven't been there, let me assure you that the Bay area is not a good place to rely on public transportation!

Once settled in my new Chicago apartment (again, see bio note), my audio system sources were a Basis 2800 vacuum turntable with Graham 2.2 arm and Transfiguration Temper moving-coil cartridge; Thor TA-3000 tubed phono preamplifier; and the Denon 3910 all-format disc player with tube output stage by Modwright (a fine-sounding, versatile player that I still use). The VTL TL-7.5 line preamplifier fed VTL MB-750 Reference monoblocks, which drove Blue Heron 2 loudspeakers from the late, lamented Meadowlark Audio. I won't here go into details of cables, accessories, etc.

But the move to Chicago was occurring simultaneously with a complicated mix of personal health and family-related difficulties that soon began to occupy more and more of my time, attention and energy. While music and audio remained important, and I continued to look for interesting hardware and software, I was all too often unable to budget adequate time to focus and write on those subjects. I did manage to document some of the equipment that came my way, but other products didn't receive the intended reviews. I apologize to the companies I disappointed during that time.

The three articles in this series will, I hope, largely remedy that situation by allowing me finally to acknowledge the fine products that have brought my system to its present happy state. This first part addresses the system's core preamplification and amplification. Part 2 will describe system infrastructure upgrades, including power conditioning, component isolation and cabling. Part 3 will discuss final touches and accessories that have raised and refined the system's total performance.

Some major improvements have already been documented. In March 2006 I reviewed the Analysis Audio Omega planar-ribbon loudspeakers from, of all places, Greece. I loved their performance and bought the review pair, expressing confidence that I would be listening to them for a long time. Fickle me — I kept wondering about the bigger Analysis speakers. If the Omegas were so good, how much better might the seven-foot-tall Ampiihitryons be? Better enough, as I recounted in October of that year that the Amphitryons as reviewed here remain my reference loudspeakers — albeit with an additional upgrade that will be described in Part 3.

The year 2008 saw a complete change to the analog front end, beginning with the phono preamplifier. I had sent my Thor TA-3000 back to the factory in Connecticut for repairs, but after a few weeks of stony silence from there I discovered that my preamp, company owner Paul Marks, and, for all I could tell, Thor Audio in its entirety had effectively vaporized — phone and e-mail disconnected, and no response to several attempts to find out what the hell had happened to my $6000 Thor phono stage. Paul Marks had said during an earlier phone conversation that he was preparing to start a new life in Brazil. I wish him well with that, but I don't appreciate his walking out on his promise to get my phono preamp back to me first! The experience gave me a new and ugly definition for "vaporware."

After a few months of searching, I finally replaced the vanished Thor with the Ray Samuels Emmeline XR-10B phono preamplifier. I had originally planned to review that little beauty, but because I had been preoccupied with the move to Chicago at the time, our esteemed Editor pinch hit for me. Steven R. Rochlin's enthusiastic review of the Ray Samuels Emmeline 10b was highly motivating, and a bit later I was able to borrow from Raymond Samuels his personal XR-10B, which included a few improvements that Steve had not heard. That XR-10B remains my phono stage today.

Last summer I reviewed the VP I Aries 3 turntable with VPI JMW 10.5i arm and Dynavector XV-1s cartridge, fully loaded in what I described as "mini-HR-X” configuration (the HR-X is VPI's flagship table). That terrific-sounding rig won both a 2008 Blue Note award and a home in my system, displacing the Basis/Graham/Transfiguration combination.

Okay, enough back story. We now come to the crux of this article about strengthening the system's core. My VTL TL-7.5 preamplifier has been upgraded to Series II. My VTL MB-750s had yielded to the VTL Siegfried monoblocks, which in turn gave way to a Spectron Musician III and then the Musician III Series 2s in monoblock configuration. The remainder of this narrative describes how those upgrades nave elevated the system's performance, forming the heart of this (IMHO) extremely musical and emotionally satisfying setup.

The VTL TL-7.5 Series II: Enhancing The Best
I guess we still need a little history. I reviewed the original TL-7.5 back in 2004. I found it the most capable, full-featured, dynamic, accurate-sounding and ergonomically satisfying preamplifier I had ever reviewed. The TL-7.5 won a place in the heart of the system and, predictably, a 2004 Blue Note award. Because that lengthy original review is only a click away for any interested reader, and because the Series II upgrade is only to the internal circuitry, I won't repeat all the physical and feature descriptions found there. Instead, I focus here on the sonic improvements resulting from the Series II upgrade.

The Series II upgrade has lower overall gain (20dB balanced, 14dB single-ended), and measures a significantly lower noise floor. VTL says the new circuit offers wider frequency response and superior musicality and transparency, while maintaining the exceptional neutrality of the original TL-7.5. I agree. New part choices enhance resolution, with more speed and presence in the top end and midrange. For home theater users, the Series II adds a fully bi-directional RS-232 control.

In the TL-7.5's dual-chassis design, the control unit contains multiple regulated power supplies and the audio switching controls, while the well shielded audio chassis is uncontaminated by AC line or control microprocessor noise. VTL says the combination of this “clean box/dirty box” approach, the balanced architecture, and the ultra-high-resolution volume control ensures a pure audio signal unaffected by external influences. Its hybrid tube/solid state circuitry employs a pair of 12AU7 tubes (a change from the original version's 12AX7s) for harmonic richness in the gain stage; the MOSFET output stage combines high-current capability with ultra-low impedance for optimal matching with amplifiers and interconnects. The subtlest qualities of recordings—size and organization, instrumental separation, and low-level sound decay—now reveal previously obscured detail. The Series II has improved bass definition, harmonic accuracy, spatial presentation and tonal purity compared to its distinguished predecessor.

Listening To The TL-7.5 Series II
Like many grizzleded audiophiles, I have owned a good number of excellent preamplifiers, and reviewed many more, before ascending to the audio mountaintop with the VTL. Out of all of those, only one stuck in my mind as superior to the original 7.5 in any way: the Wavac PR-T1, a purist-oriented line stage retailing for (gulp!) $30,000, seemed to me slightly superior at capturing the subtle colors (not colorations!) of instruments and voices. But in addition to its daunting price, the Wavac was no match for the 7.5 in flexible connectivity, which is very useful to a reviewer, and the VTL was also superior in other major sonic considerations such as bass response, macro dynamics and soundscape breadth. (Soundscape depth and detail retrieval were pretty much a wash between the two.)

When VTL announced the Series II upgrade, I consulted VTL's proprietors, Luke Manley and Beatrice Lam, to get their take on how the upgraded version would differ from the original. After all, the cost was far from trivial: $6000, reflecting the difference in price between my original 7.5 ($12,500) and the new Series II ($18,500). For six large, after all, one can buy some pretty fair preamps! What won me over, finally, was Bea Lam's eloquent description of the improved color and vividness delivered by the Series II. Since Bea is one of the best listeners I have ever known, I decided to take the chance, spend the money, and see if my beloved 7.5 could now equal that darned Wavac in the one area mentioned above.

I'll bet you can predict how this story comes out. When my TL 7.5 arrived back from VTL it took very little time for me to realize that this was now, unequivocally, the preamplifier of my dreams. The TL 7.5 Series II retained all of the virtues of the origina, and more. Bass seemed a tad tighter and more focused; micro-dynamics were noticeably more precisely captured; spatial dimensionality was perhaps slightly more dramatic; and, most importantly, the promised improvements in instrumental and vocal "color" were vividly in evidence.

I reached those conclusions, after the usual couple of weeks of round-the-clock burn-in, by trotting out some of my reviewer's warhorses, recordings I know intimately and have used for years in equipment comparisons. First up was the celebrated Dorati Firebird — one of the greatest orchestral recordings off all time, IMHO — in the single-sided 45 rpm Classic Records reissue. This recording has always sounded spectacular, and the big moments were as dazzling as ever. The "Infernal Dance" at high playback volume could still pin me happily against my listening seat, and what Igor Stravinsky once described as his "widescreen Technicolor finale" was still transporting. But repeated playings revealed that the many quieter, more lyrical passages in this score were now more involving than I remembered, especially woodwind solos, delicate percussion, and strings. There was just more there there! A similar epiphany occurred when I put on my treasured RCA Red Seal LP of the Charles Munch/Boston Symphonie Fantastique. I have always especially admired how this 1962 recording captures the bite of the BSO's low strings, especially in the "March to the Scaffold." But now, in addition to the "bite" and impact I was accustomed to, there was a new bloom to those strings, an enhanced sense of the warm resonance of those large instruments, together with a more vivid capturing of the bowing; and the leading edge of the brass had greater wallop. Uncanny, really.

This sense of greater immediacy and emotional connection to the music was equally evident with digital recordings. A perennial favorite CD, never far from my player, is the Reference Recordings disc of Leonard Bernstein's music by Eiji Oue and the Minnesota Orchestra. String tone on this CD has always been extraordinary, but now both the tonal beauty of the violins and the sense of perceiving individuals playing together rather than just a mass of players were definitely enhanced.

The virtues of the TL 7.5 Series II shone through in popular music as well. I pulled out a very severe test. Emmylou Harris's Wrecking Ball from 1995 is the most unique release of this great singer's career, but also the most problematical for an audio system. Daniel Lanois' production is incredibly dense and layered, so much so that when I originally reviewed this release I criticized his "mannered, murky production." But over the years I have discovered that every time I improve my system I can go back and hear more details that were previously obscured. With the Series II, it happened again — on track after track, it was just easier to hear through the formerly cacophonous mix of instruments and backing voices, and Emmylou's vocals, never more intense than on this recording, are even more moving.

Turning to Alison Krauss and Union Station Live: this fabulous contemporary bluegrass album, demo quality to begin with, was now even more engaging, with Krauss's "high lonesome" soprano and world-class fiddling, as well as the awesome virtuosity of the whole band, seeming to move bodily into my listening room. (If you think you don't like bluegrass, you should try this one; to me it's simply irresistible.)

Summing Up The TL-7.5
Sonically, the VTL TL-7.5 Series II remains at the top of my preamplifier rankings. The original was a fabulous component, and the gains in fully capturing the color and immediacy of recorded performances place the Series II at a stratum that few competitors achieve. Couple that sound quality with the beautifully conceived ergonomics and comprehensive connecctivity, and what you have is a complete reviewer's tool — or a great starting point for any ultimate-performance system.

Speaking of ergonomics, I want to especially commend the 7.5's remote control. From my listening seat I can remotely set volume and balance, select any source, mute the output and, importantly for me, instantly check/flip electrical polarity. Some listeners are not bothered by out-off-polarity/phase playback, but for those of us who are sensitive to it, this is a BIG benefit, especially being able to do it from the listening seat. Bravo, Luke and Bea!

I do wish this thing didn't cost so much. Much of that cost reflects the stunning build quality that VTL has lavished on its flagship preamplifier. But the 7.5 also has many features I will never use, especially home theater-oriented capabilities. In an ideal world, perhaps, we could have a more stripped-down "purist" design, with more limited connectivity and fewer luxury features, at a much lower price. I suppose the company's TL-6.5, a single-chassis component with sonic technology trickled down from the 7.5, may be a step in that direction at around half the cost of the 7.5, but I have not heard the production version of that preamp.

The bottom line? If you can afford it, I know of no finer line preamplifier than the TL-7.5 Series II. If you already have the original 7.5, which suggests the likelihood of a very ambitious audio system, you are probably the kind of listener who will relish the Series II's highly worthwhile improvements, as I have.

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.

The 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!

Click here for part 2 of Building A Reference System.

Pricing
Analysis Audio Amphitryon Loudspeakers $24,000 per pair

Bybee 'Super Effect' Internal A.C. Bullets option: $2,000
V-Cap option: $1,400
Bybee & V-Cap options, ordered together: $3,300

Spectron Audio Musician III Series II: $7,195
Internal bridge-mode wiring: $75 per amplifier

VTL TL-7.5 Series II line preamplifier: $18,500
     Upgrade to Series II: $6,000

VPI Aries 3 Turntable: $7700 as reviewed

Manufacturers
Analysis Audio USA 
Website: www.AnalysisAudioUSA.com

Bybee Technologies

Spectron Audio
Website: www.SpectronAudio.com

Vacuum Tube Logic, Inc.
Website: www.VTL.com

VPI Industries Inc.
Web: www.VPIIndustries.com