WAVAC PR-T1 Line Preamplifier
The stuff that dreams are made of.
Review By Wayne Donnelly
here to e-mail reviewer.
When it comes to audio equipment, I'm firmly in the "Handsome is as handsome sounds" camp. I've never chosen any component or loudspeaker based on looks, although some mighty fetching hardware has passed through my listening rooms in years of reviewing. But when dazzling visual appeal and great sound come wrapped in the same package, that's serendipity. For this writer, no manqué in audio more consistently combines drop-dead gorgeous cosmetics and breathtaking musicality than Japan's WAVAC Audio Lab, and never has that been truer than with their magnificent no-holds-barred PR-T1 line preamplifier.
Even in an industry where five-figure price tags are as common as pollen in spring, the prices of WAVAC components can be daunting. The PR-T1 retails for $30,000, for a five-input, four-tube line stage devoid of anything resembling bells and whistles
— not even so much as a remote volume control. After several happy weeks of living with this beauty, I'm not inclined to complain about that price. While $30K puts the PR-T1 well out of my affordable range, and that of most readers as well, I feel blessed to have experienced its extraordinary music making. I'll never afford a Bentley convertible either, but I'd jump at a chance to take a nice long ride in one. I'll bet you would too. So come cruise vicariously with me through the enchanted sonic landscape conjured by this fabulous preamplifier.
Two-chassis preamplifiers are not uncommon among elite preamplifiers; the second piece is typically the power supply. My reference VTL 7.5 takes that concept a step further, with a "clean box/dirty box" architecture that places not only the power supply but also all digital switching, controls and the remote sensor in one chassis, leaving only the audio circuit and input/output jacks in the heavily shielded and totally sealed second enclosure.
The PR-T1 takes that concept even further. The very substantial power transformer resides in its own enclosure, connected by heavy-duty cables to the power supply control chassis. That, in turn, interfaces with the audio chassis via another set of cables. The cables and fittings used for these connections are definitely industrial grade, and are said by WAVAC to be designed for optimum power transfer. (I believe it.) The interface cables also allow the audio control unit to be physically separated from the other, "dirtier" chassis
— one of many factors that contribute to the uncanny quietness of the PR-T1.
The very rigid enclosures for the power transformer and power supply are fabricated with 10-millimeter-thick metal plates. Both have sculpted fascias in the lovely champagne-toned finish so familiar to WAVAC fans. The audio control chassis is carved from a solid block of aluminum in that same champagne finish. Access to the tubes is through a panel on the bottom; the eye sees a flawless, unbroken shape
— museum-worthy — that is as beautiful a piece of audio sculpture as these eyes have seen.
The fascia of the audio chassis features the large, bulbous volume knob and small knobs for input selection and left/right channel level trim, in a subtly harmonious contrasting mirror-finished silver. The volume knob is a highly precise stepped attenuator. Its detents are at once precise and sensuously silky in feel, and this tactile quality contributes to the pleasure of using the preamplifier.
The circuitry illustrates the virtues of 'less-is-more,' especially when the minimalist circuit is executed so lavishly. The transformer-coupled circuit design has no capacitors in the signal path, contributing significantly to the spectacularly clear, fast, neutral tonality and (in my experience) unexcelled resolution. Essentially the audio circuit can be summarized in a single line:
Input transformer > 5814A/12AU7 tubes > output transformers
Frequency response is wideband and totally flat: 20Hz to 100kHz (-0dB). WAVAC did not supply a signal-to-noise specification, but the PR-T1 is easily the quietest all-tube preamplifier I have ever used, and it rivals even high quality solid-state units in that respect.
The PR-T1 replaced my VTL 7.5 preamplifier in my downstairs reference system. Most of the listening was through the massively powerful VTL 750 Reference monoblock amplifiers, driving Meadowlark Blue Heron2 loudspeakers. For brief periods toward the end of the review process the VTLs were replaced by the new 500-watt-per-channel Spectron Musician III stereo digital amplifier and the 50-watt WAVAC MD-805m monoblocks (both scheduled for review). The PR-T1 drove each of those amplifiers flawlessly.
The special qualities of the PR-T1 were evident from the first moments of listening, and were consistent in every system configuration I tried. I heard no hi-fi artifacts, no glare or grain, no exaggeration or emphasis across the audible spectrum. The musical presentation was sweet and relaxing, but always truthful
— never colored or soft, and never masking the shortcomings of any vinyl or digital source. Extraordinary dynamics, accurately scaled from explosive orchestral
tuttis down to the subtlest, most delicate shadings captured on the micro end
— the latter quality enabled by the blackest audible background I have heard from a tube preamplifier.
Fun With Tube Rolling
The stock tubes offered by WAVAC are Philips 5814A/12AU7. However, U.S. distributor tmh audio currently substitutes (at no additional charge) NOS Mullard CV4003 "box plate" tubes, and my first days of listening were with those. As previously stated, I found the sound enchanting; no cause for complaint with the Mullards. But a dealer friend, Jeff Wells of Audible Art in San Jose, Calif., offered to bring over some of his favorite NOS 12AU7s for comparison, and things got even more interesting.
We began with circa-1960 RCA black plate 12AU7s. Those were brand-new, and took several days to burn in fully. An amazing moment
occurred about 10 days into this stage of listening. We were deep into the latter movements of the new SACD of Mahler's
"Resurrection" Symphony, performed by Michael Tilson Thomas and the San Francisco Symphony and Chorus. I had thought the tubes were completely burned in, but in the middle of a choral passage the whole soundscape suddenly "morphed." All at once the back wall of Davies Symphony Hall receded. The offstage horns took on a more distant perspective. The harmonics of strings, winds and brass were suddenly and startlingly richer and even more beautiful. Now the tubes were fully burned in! I don't recall ever hearing such a dramatic development in the space of a second prior to that moment.
Next came a set of ultra low-noise 12AU7 variants, RCA 5814s of similar vintage. The latter tubes were already well seasoned, and I quickly perceived even more inner detail and sheer tonal beauty. Near the end of the Mahler, as the chorus swelled dramatically, I suddenly felt
goosebumps as I distinctly discerned the voices of the soprano and mezzo-soprano soloists, singing in unison with but clearly audible in front of the massive chorus. Great stuff!
To a greater extent than previously, with the PR-T1 in play the system remained completely open and unstrained at much higher than usual playback levels (and
chez Donnelly, "usual" is pretty robust, especially with Mahler).
Well, not quite — at least for this listener. Since acquiring my
VTL 7.5 preamplifier, I have gotten used to comprehensive remote control capability
— volume, polarity, balance, mute, source selection — and I prefer not to have to get up and cross my pitch-black listening room, thereby risking the yowl of a stepped-on cat to adjust the volume a click or two up or down. This may be of no concern to other listeners, and of course I recognize that manual volume adjustment is completely consistent with the minimalist philosophy that underlies the PR-T1. And too, there's that sexy-feeling volume
More significant to me is the absence of a switch for electrical polarity (phase) correction. Given the lamentable inconsistency of polarity on recordings, sometimes even from track to track on a CD, polarity switching from the listening seat is one of the best ways to hear one's system consistently at its best. Of course after years of hearing out-of-phase music over home audio systems and in demo rooms at trade shows, I realize that many (most?) listeners either can't hear or don't care about incorrect polarity. It also seems characteristic of Asian high-end designers to ignore polarity correction. (I recall my bemusement [especially given the brand name involved] a few years ago that the highly trumpeted $28,000 Accuphase two-box SACD player offered only a virtually inaccessible back-panel manual switch for phase reversal.) I suspect that for WAVAC the absence of polarity switching on the PR-T1 is partly a reflection of the company's 'less is more' design approach. I must admit that through this wondrous-sounding preamplifier even a reverse polarity recording sounds gorgeous. But on the few occasions that I compensated for incorrect polarity by reversing my speaker cables at the loudspeaker, the sound was even more beautiful with proper polarity. Call me crazy, but it matters to me.
Longtime readers may recall that I have placed two preamplifiers
— the $18,000 solid-state John Curl/CTC Builders Blowtorch and the $12,500 tube/solid-state hybrid VTL 7.5 - in my personal pantheon. The PR-T1 definitely belongs with those champions, and perhaps ranks a smidgen higher.
For most of us, the $30,000 PR-T1 is the stuff that dreams are made of. I can't even begin to make a reasoned analysis of its value for the dollar. As the old saying goes, if you have to ask how much, you can't afford it. Regrettably, I have to ask. But if you are in the fortunate position of being a perfectionist audiophile with abundant discretionary funds, I say go for it! Based on the tube-rolling experiences described above, I feel comfortable saying that the audio circuit of the PR-T1 is so pure that in effect it has no sound of its own; it will sound like the tubes you put in it. A masterpiece, visually as well as musically.
Type: vacuum tube stereo preamplifier
Frequency Response: 20Hz to 100kHz (-0dB)
Inputs: three single ended (RCA) and two balanced (XLR) or
four single ended (RCA) and one balanced (XLR)
Other custom combinations available
Outputs: single ended (RCA) and balanced (XLR)
Other custom combinations available
Main Chassis: carved from 70mm solid block of aircraft aluminum
Power Supply & Power Transformer: constructed using thick 10mm plates for rigidity and sonics
Dimension: 380 x 390 x 86 (WxDxH in mm) main unit only
Weight: 69 lbs (all 3 chassis)
Warranty: one year parts-labor; six months on tubes
WAVAC Audio Lab - Sigma Co. Ltd.
1404-26 Nakada-Machi Yonezawa-Shi
North America Distributor
PO Box 751681
Dayton, OH 45475-1681
Voice: (937) 439-2667
Fax: (928) 441-7418