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VAC Phi 200 Tube Monoblock Amplifier Review

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VAC Phi 200 tube monoblock amplifier

Pay Not To Play

I would pay good money to have Kevin Hayes, owner and designer at VAC, listen to an amplifier. If you purchase a Valve Amplification Company product you are paying Kevin to listen to your product extensively before you use it, and you should be elated. He listens to everypiece of gear which leaves VAC’s premises. Again, it is Kevin who listens, not some other worker. He is the final arbiter of sound quality on every piece of VAC gear which is sold. It is a very good thing when a knowledgeable, passionate person is at the helm of an audio company and singularly treats your component as if it is his. That kind of personal service costs more, but brings some distinct advantages to the audiophile searching for top sound.

Kevin is among the most well read, technically informed tube preamp and amp manufacturers in the entirety of the high-end two-channel world. When he was a teenager he pored endlessly over a tattered copy of the Radiotron Designer’s Handbook, and remarks that he has, “… collected and read thousands of pieces of literature on the creation, capture and reproduction of sound.” In describing this he states, “I don’t know why God gave me this passion for music and its reproduction, but it’s been part of the fabric of my being for as long as I can remember.” I can relate to that sense, as when I was in grade school I was already glomming onto a 1977 Lloyds all-in-one system (8 track, turntable and receiver), and shortly after assembled my first rig. I also have felt driven to assemble stereo systems in a search for “musical meaning” in sound reproduction. Consequently, this article brings together the deep desires of two men intensely searching for as close to musical perfection as can be achieved in an audio system. Kevin spends an inordinate amount of time listening to a piece of equipment until he deems the design worthy. I have listened to an inordinate amount of gear, looking for the perfect sound. That search for perfect sound has led me to VAC.

Transformation of An Audiophile

In younger days, while Kevin was developing into a tube amp impresario, I was not so passionate about tube amps. I came of age during the ascendancy of solid-state technology and was inevitably swept up in it. When I began to assemble stereo systems I was convinced that solid-state trumped tubes on principle. I made the same assumption as thousands of music lovers; the smaller, cheaper, newer technology had to be better. How simplistic that viewpoint was!

Lurking in my mind was a misperception that, in some respects, still plagues the populace – that anything arising from an older technology was suspect of being inferior. Perhaps you have witnessed a person who sees a tube preamp or amp declare, “Tubes! I didn’t know they still made audio equipment with tubes.” Unless a person consumes Hi Fi periodicals, visits the right dealer or internet forum, or attends a Hi Fi show, the bias is likely to remain. Tube amps still seem on the face outdated to many and are treated as suspect devices by others. I see comments on audio sites from individuals who approach tubes as though they are inherently untrustworthy, as if they degrade sonically so quickly and have such poor distortion specs that one can’t be certain of their performance. To such individuals, solid-state is nigh unto infallible. I was like that for a long time. Part of it was that I was not into DIY, and could not afford finer tube gear; part of me wanted to believe that I sacrificed nothing sonically for sticking with solid-state because on the whole it was cheaper.

Over the years I have slowly been remade as an audiophile, morphing from a staunch solid-state supporter to a tube amplifier enthusiast. With growing experience hearing tube amps in quality systems, I was forced to admit that they have as much, and in some instances more efficacy than solid-state designs. I now find that I am drawn toward tube amplification like the proverbial moth to the flame. I am increasingly using tube preamps and amps in systems by preference.

During this process I have also revised my thinking in terms of use of tubes with less efficient speakers. Experience with the amp under review here, the Valve Amplification Company (VAC) Phi 200, has cemented my belief that solid-state is not the only game in town for electrostatic and magnetic planar speakers. In fact, paying attention more to the timbre of the music, a strong argument can be made that tube amps are the ideal for panel speakers; jacking up Watts is certainly not the only variable in attaining a pleasing result with panels.

VAC Phi 200 Tube Monoblock Amplifier

Tubes and TUBES

There are tubes, and then there are some: not all tube amps are created equally. When approaching tube amplification one must determine early on which direction will be taken, the low-power linear circuit topology such as SET (Single-Ended Triode) amps, or larger high-output power stages with push/pull topology and a battery of output tubes. There is an alluring attribute of clarity in many of the simpler, lower power amps which is difficult to match in the higher-powered designs. With economical tube amps, one usually has to make a trade off, purity for power, or vice versa. It is rare to find both in abundance.

Having used both types I have at this time concluded that I prefer to trade an extremely small amount of clarity for radically increased power. Ideally, I would never have to do this, but I found myself longing for dynamic power and weight when hearing low-power amps. They simply have a tendency to sound wussy compared to higher-powered tube amps, even when paired with extremely efficient speakers. The search for ultimate-sound low-power amps radically limits the number of speakers to be practically considered, a trade off that I am not willing to make.

Given that a system is influenced in terms of signal purity throughout the chain, I determined that I would sacrifice marginally at the amp when it came to clarity and make up the deficiency in the other components, particularly the source. I have found the ability of an amp to create robust dynamic power an aspect too important to skimp on; but the sense of clean power can be enhanced through careful selection of attending components, especially the source and cabling used with the preamp/amp combo.

Let it not be misconstrued that I am advocating any intentional lowering of standards in sound quality. When confronted with real-world limitations and budgets for gear, one simply must make choices leading to the best result. In no audio system is there an absolutely perfect route to ideal sound; there are always trade-offs. I seek to trade off the potentially most damaging shortcomings for ones which are potentially least damaging. A good example is the use of power conditioning components, which invariably involve a trade-off of absolute clarity as they extend and complicate the system. One must assess whether the influence of the conditioner is overall a positive or negative.

At this point in time I do not typically use power conditioners in systems, as I find that every one I have used has degraded the clarity of the system in an absolute sense. I am the first house in our subdivision and the power transformer sits right outside our back door. I have clean, noise-free power lines and despite trying many power devices which utilize filtering I have always ended up returning to the good ol’ plug-in-the-wall method. This does not mean power treatment is without merit, but simply that I do not benefit greatly from it. Thus, the elimination of the power conditioner improves the overall system clarity and the amplification benefits.

A very practical consideration in terms of speaker selection also necessitated this decision to settle on big amps – I enjoy huge panel speakers. These are typically difficult to drive, effectively sidelining smaller tube amps. One possible panacea may be the gain feature of the Ayon Audio CD-5, an extremely fine all-in-one player/preamp, with settings of 4, 6, and 8 Volts output. With it, one has the option of matching smaller amps with less efficient speakers. Save for that indulgence, necessity exists to have ample power to drive a 2-ohm load, and sometimes much lower, typically found in larger panel speakers.

Love Affair with Panel Sound

My first experience hearing a panel speaker was in St. Louis at a high-end shop where, shamefully, I cannot recall the name, I was overwhelmed by the majesty of the Magneplanar Tympani. I never dreamed sound could be like that! Over the years I have had the pleasure of hearing a wide variety of pleasing panels. I flipped speakers annually, if not more often, and found myself bouncing between dynamic and planar offerings. In recent years I have been migrating toward full range ESL (Electrostatic Loudspeaker) technology and have adopted the King Sound The King as my reference. Recently, I added a new version of the hybrid dynamic speaker from Legacy Audio, called the Whisper DSW. The Whisper utilizes a 4” magnetic planar midrange, so it also gravitates toward panel sound.

As my reference speakers have been upgraded over the past decade, so also has my amplification. In that process, I have expanded from the solid-state end of the amp spectrum to hybrids, to tube amps. This was quite unexpected for someone sold on the merits of solid-state. Once I learned that powerful enough tube amps existed to do the job, I thought that they were all priced into the stratosphere. Wrong. I ended up settling on the compromise position – tube hybrid amplification. My affordable favorite is the capable and beautiful pair of Pathos Classic One MkIII amps operating in mono mode.

Of late I have been on a search for a premier amplifier to drive either the DSW or the King. This is no small feat; the Whisper, though having four 15” bass drivers per channel and 95 dB sensitivity is a 4-0hm speaker and an open baffle design. Consequently, it is rated at 22 Hz – 30 kHz +/- 2 dB. It hits 20 Hz comfortably, but to extract larger subwoofer-like bass from it requires an amp with not just enough watts but also higher current. To get both of those in a tube amp usually costs much more than a solid-state amp.

On the other end of the speaker spectrum, the Kingsound King is a tough-to-drive electrostatic. It dips to approximately 1.8 Ohms at 20kHz, and though it has a more friendly nominal impedance of 6 Ohms, sensitivity is at 83 dB. These two speakers could hardly be more different from each other! It did not take long to learn that solid-state amps, while providing ample power, introduced problems in terms of sounding technical with one or the other speakers. The Pathi took me way down the road toward perfection with both speakers, but the ultimate answer was not to come until the VAC Phi 200’s showed up at my door.

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