Review: Valve Amplification Company Phi 300 Tube amp

Category: Amplifiers

With no small amount of anxiety, I recently replaced my VAC Renaissance Signature 70/70 amp with VAC’s newest amp, the Phi 300. The Ren Sig 70/70 is a sonically and visually gorgeous amp, with detail, power, control and the most 3-dimensional soundstage projection that I had ever heard from any amp. Why fix what isn’t broken?

The Phi 300 now has about 90 hours of playing time on it in my home. The manual states that it was played for 48 hours before it left the VAC factory, so figure that it has close to 140 hours total time, and maybe that should be adjusted downward to account for the effects of shipment. In any event, I think it has largely settled in to its basic performance level, although there may be marginal improvements over another 100 hours or so of play. This amp can be run in either triode or ultralinear mode, with single-ended or balanced interconnects. I have tried all combinations and have found, at least in my system, that it sounds best driven with single-ended interconnects and operated in the triode mode. I have used only the stock VAC tubes.

Before evaluating the Phi 300, let me set forth the associated equipment. The preamplifier is the VAC Renaissance Signature Mk II with the inboard phono stage (power cord: Stealth Cloude 9). The digital front-end is the Zanden 2000 Premium Transport and the Zanden 5000 Signature DAC (power cords: Michael Wolff Carbon Ribbon Source). These units (exclusive of the power supplies to the transport and DAC) are placed on a Sistrum SP-5 rack. The analog front-end is a Kuzma Stabi Reference turntable, with a Triplanar VII tonearm and a ZYX UNIverse X-SB cartridge. The turntable is on a Neuance platform that in turn sits atop a homemade turntable stand made of Ipe wood (with a high rigidity-to-mass ratio). The Phi 300 is on a Sistrum SP-101 stand and connected via an Elrod EPS-3 Signature power cord directly to the outlet (Furutech FP-20A(R)). Speakers are the Verity Audio Lohengrins. Power is supplied through an old Topaz 10kVA EI-style transformer, a 350 lb beast that is hard-wired in the basement to produce a balanced 60-0-60 output with a technical ground that is then routed through a Tice Power Block IIIB Signature for all components other than the amplifier. Interconnects are Stealth Indra and M-21, and speaker cable is Stealth Ultimate Ribbon in a custom bi-wire configuration. The room is approximately 21’ wide by 29.5’ long.

The first thing I noticed after hooking up the Phi 300 was that it was fast, very fast. Perhaps the only drawback of the Ren Sig 70/70 of which I was aware before getting the Phi 300 was that it was not as fast on transients as other amps I had heard. I think this is largely due to the 300B tube, as it tends, at least in my experience, to produce a richer sound at the expense of some speed. My old VAC PA 100/100 (another classic VAC amp) with KT-88s, for example, was marginally faster than the Ren Sig 70/70, but was far behind it in every other category. The speed of the Phi 300 has not really increased over the break-in period. It remains the fastest amp I have ever heard. Period.

The second thing I noticed at the beginning of the break-in process is that the Phi 300 produced a deep, but well controlled bass. I always thought the bass on the Ren Sig 70/70 was superb (and it is), but it was inferior in comparison to the bass from the Phi 300 right out of the box. After about 60 to 70 hours of playing time, however, the bass from the Phi 300 improved dramatically. It is enormously deep; it has a texture to it that enables you to experience it in a way that I can only describe as being more physical than sonic; and most incredibly, it has serious “slam” and it is extraordinarily well controlled. It produces the best bass I have ever heard, even from some of the most expensive solid-state amps that, generally speaking, are better at bass reproduction than tube amps. The Phi 300 trounces them in this department.

The third thing I noticed at the outset was that the 3-dimensional soundstaging and imaging just weren’t there. The soundstage was compressed, and the imaging was sloppy. My anxiety over selling the Ren Sig 70/70 was a little elevated at this point, to say the least. At around 60 to 70 hours of playing time, however, this changed. In a big way. The soundstage is wide (extending well beyond my speakers) and high and deep (extending behind the rear wall). Imaging is precise. Instruments and voices are clearly discerned at precise points across this expansive soundstage. The most amazing part, though, is that there is an extraordinary amount of detail without any sacrifice of that legendary VAC holographic, airy sound. How VAC managed to get this amount of detail while exceeding the richness and lusciousness of their 300B based amps is a complete mystery to me.

So, the bottom line is that this amp has lightning speed, incredible bass with slam and control, exquisite detail across the entire audible spectrum, the ability to handle with ease dynamic contrasts from ppp to fff; and it projects an expansive soundstage with amazing imaging and an airiness and delicacy that I can only describe as magical. Or perhaps stunning. Or perhaps jaw-dropping. Let me try to share a few recordings with you. I always find this the most difficult thing to describe, but I’ll try.

Sonny Rollins’ “I’m an Old Cowhand” on Way Out West (XRCD24, JVC) is clean, crisp and balanced. The timbre of the tenor sax is completely natural; you can experience the reediness of the notes. The bass is deep, fast and punchy; and the cymbals and snare drum are reproduced with amazing clarity and crispness. “Prologue” on Dave Grusin’s West Side Story (CD, N2K-10021) is a great test of the sonic ability of any system or component. It sounded great with my Ren Sig 70/70. It sounds noticeably better with the Phi 300. The greater speed makes a huge difference in the transient attacks throughout this piece, whether drums, cymbals, trombones, muted trumpets or the tightly syncopated saxophone passages. “I Feel Pretty,” from the same CD, illustrates the ability of this amp to produce a layered soundstage, with speed, detail and the ability seamlessly to produce the most delicate of sounds against the most forceful. The airiness of the flute, coupled with the almost perfect timbre of each strike of a piano key and the low frequency extension on the piano and high frequency extension on the triangle, give rise to a truly “you-are-there” experience. One of my favorite CDs is Queen Latifah’s The Dana Owens Album (CD, A&M). Every single song on this album, which is wonderfully recorded, is a winner. (If you think Queen Latifah could perform only rap or hip-hop, you need to buy this CD immediately.) Her rendition of “Simply Beautiful,” performed as a duet with Al Green, shows what the Phi 300 can do with vocals. You can almost feel them in the room with you. This amp retrieves all of the small breaths, sighs and tremolos, and then places the two singers side by side in the rear of the soundstage – she slightly to the left of center and he slightly to the right of center – that make this seem as if it is personal performance for you.

Patricia Barber’s Companion (LP, Premonition Records 1999) is one of my favorite Jazz LPs, given both the content and the high quality of the recording. The bass on “Use Me” is luxuriously rich, not only because it is so deep and so well controlled, but also because the speed of the amp precisely reproduces each bass string pluck. Seriously deep bass with detail and speed. Wow! “Let It Rain” demonstrates both the speed and detail in the mid- and higher frequencies. Every fret movement on the guitar is picked up with so much detail that it is as if you are five feet away. The cymbals are detailed and delicate, with just the right amount of decay. Barber’s singing is rich and beautifully positioned in the middle rear of the soundstage (it was slightly more forward on the Ren Sig 70/70). “Black Magic Woman” is a magical, intoxicating experience, with the occasional applause from the audience layered across the soundstage in such a way as to make you feel that you are there with them, but with the best seat in the house.

The speed, retrieval of detail and decay of the Phi 300 are illustrated in “Polonaise de la Concert, Op.4,” on Itzhak Perlman (LP, EMI Japan EAA-85060). Each note from Perlman’s aggressive violin performance is fast, precise and detailed, while the accompanying piano notes (from Samuel Sanders) linger with a perfect tonal balance and decay. It sounds as if they are right there in front of you. Rimsky-Korsakoff’s Scheherazade, performed by the Chicago Symphony (Reiner), (LP, Classic Reissue of RCA LSC-2446), is a serious test of any system or component. It has extensive dynamics ranging from delicate ppp violin and harp solos to powerful fff full orchestral movements. The ability of this amp handle those dynamic extremes with total ease, to reproduce the reediness of the oboe and vibrations of the bows against the violin strings while projecting from the rear of the wide and deep soundstage an incredibly rich and deep bass with the fastest timpani you’ve ever heard (short of a live performance) is nothing short of extraordinary. This is one of my favorite classical performances. It was beautiful on the Ren Sig 70/70. It is magnificent on the Phi 300, which brings the reproduction to another level.

The “Trees They Do Grow High,” performed by Pentangle on Sweet Child (LP, Reprise 2RS 6334), is a beautiful ballad. The speed, detail, deep bass capability, and holographic soundstaging and imaging of this amp make the combination of Jacqui McShee’s silky voice, Danny Thompson’s double bass, Bert Jansch’s and John Renbourn’s acoustic guitars and Terry Cox’s drums and cymbals so vivid and real that it is just plain spooky. It is sheer pleasure listening to this on the Phi 300.

The bottom line is that the Phi 300 just does everything right. It presents the most detailed, natural, rich and holographic sonic image that I have ever heard. It is dead quiet, it handles the most delicate of notes to the most forceful of notes with total ease, and it seamlessly handles the deepest bass (which becomes more of a physical experience) to the highest frequencies. I cannot think of a single shortcoming, which puzzles me because I have always believed that all high-end audio components are imperfect as the designers must strike balances among competing factors. Having heard the Phi 300 after a sufficient amount of break-in, I think it is fair to say that it is the finest amplifier I have ever heard. In my view, the Phi 300 is not evolutionary; it’s revolutionary.

Associated gear
VAC Renaissance Signature Mk II preamp (with inboard phono stage)
Zanden 2000 Premium CD Transport
Zanden 5000 Signature DAC
Kuzma Stabi Reference Turntable
Triplanar Mk VII tonearm
ZYX UNIverse X-SB cartridge
Verity Audio Lohengrin speakers
Topaz 10 kVA EI-style Transformer
Tice Power Block IIB Signature power conditioner
Sistrum SP-5 rack
Sistrum SP-101 amp stand
Stealth Indra IC and Ultimate Ribbon speaker cables
Power cords: Michael Wolff Carbon Ribbon Source, Stealth Cloude 9, Elrod EPS-3 Signature
Ag insider logo xs@2xvac_man
Sam, I have the Phi 220 monoblocks with 220 watts a side and they handled my Wilson MAXX extremely well for a tube amp. Recently, I bought the Zu Definitions and considered selling the 220's as I don't need as much power now. Kevin told me the 160's would give me greater punch in the low end than even my 220's and still much of the sonic benefits of the Phi 220's with a little less resolution. Talk to Kevin, he is always straight with you and will give you his best idea on what to do.
Excellent, substantive review, Vac Man! I'd also be interested to read your observations regarding the Lohengrins. I've heard them at CES but in less than ideal conditions. Can you draw a comparison to either the Parsifal Encores - which I've owned and enjoyed for over five years - or the Sarastros?

All in all, a very impressive system.
Does anyone know if the Phi amps use circuit boards? The Renaissance amps are point-to-point wired.
Kevin is now up to the Phi 300.1 which I ordered several weeks ago, in part due to your glowing review. Since you haven't posted here for a while, I was wondering how your Phi is doing after 11 months - I'm hoping it sounds even better. I am also interested in talking to you about your Lohengrins - please send me an e-mail if you'd like.

Fplanner2000, I would be interested in your impression(s) of your new Phi 300. I would imagine that you'll fall in love with its performance. Perhaps you could start a new thread with your own review. I would look forward to that. Enjoy your new amp.