Valve Amplification Company Signature IIa Preamplifier

The phono also performed with wonderful tonal weight, detail, and timing via its mm inputs with my Ortofon GM Mono Mk II SPU cartridge (3.0mV). Dave Brubeck’s “Blue Rondo à la Turk” from the immortal Time Out LP [Columbia] spun with speedy, sparkling highs from Brubeck’s piano. There was a propulsive momentum with drums, bass, and piano tripling in unison on the famous theme. Paul Desmond’s alto sounded cool and sweet with small dynamic explosions. When Joe Morello hit the fan of his ride cymbal repeatedly, punctuating the rhythm, the sound shimmered out in time with the beat. But when he hit the cap, the cymbal rang like a damped cowbell. The Signature IIa with the Herron monoblocks created a sound that had real living presence to it.

Finally, I paired the Signature IIa with my VAC PA-100/100 stereo amp (based on the 1947 Williamson circuit). This sound was always rich and resolving, particularly suited to voices and strings. Returning to digital playback, I selected a piece of Baroque sacred music that never fails to move me. Its 13th century text is a sorrowful hymn to Mary set by Giovanni Battista Pergolesi in 1736. I’ve numerous recordings of it, but I chose Stabat Mater: A Tribute to Pergolesi [DG], a recent CD I ripped to Apple Lossless on my iMac’s hard drive running Leopard 10.6.8 and played back via iTunes (10.5.3) and a JoLida Glass Tube DAC. With Anna Netrebko (soprano) and Marianna Pizzolato (contralto) singing with the Orchestra dell’Accademia Nazionale di Santa Cecilio directed by Antonio Pappano, the title tracks opened with a beautiful duet, Stabat Mater delorosa, interweaving vocal parts but offering distinct timbres between singers. Pizzolato’s contralto was at first smoother, more liquid, sometimes with a slight stylistic thickness in her throat. She sang with rapid tremolos and brilliantly suspended topnotes that spun out over a conjunct bassline. Netrebko’s soprano sounded thinner, but much more agile, and, partly because of the close-miking, partly due to the Signature IIa’s resolving abilities, I heard very subtle shadings of grief and passion in her voice as she addressed herself directly to Mary mourning the death of Jesus. I found this level of detail extremely touching and appropriate to the somber dignity of the music. And the Baroque violins, played without modern vibrato to sweeten the sound of the bow crossing the strings, nonetheless sounded rich, lush, and detailed.

Through the rest of the eleven movements, both singers had numerous shifts of vocal intensity—moderate volumes rising to full-out song, then whispering, and full-out again with passionate topnotes held a good long while, attesting to the system’s power. And when they sang together, there wasn’t just a layering of their voices, but a thrilling intensity too, as they reached dramatically, with precisely differing timbres and vocal registers, for volume and harmony together. The system with the Signature IIa preamp sang along, never ragged or harsh in the difficult sustained topnotes and dynamic peaks, always producing a clear and emotionally compelling sound sensitive to all the glorious subtleties of this superb vocal performance.

Kevin Hayes has really outdone himself with the VAC Signature IIa preamp. A statement piece at a luxury price, it plays music with extraordinary finesse and drive, accurate timbres, spaciousness in the soundstage, swift attacks and aching decays, and an even spectral balance. Of all the preamps that have been in my system, it is the one that most wisely balances the ofttimes contradictory qualities of superior drive and great finesse. Completely versatile, it can be voiced by rolling tubes to suit just about any ear, has numerous inputs for a multitude of sources, can be fitted with an outstanding phonostage, and be run balanced or single-ended. It performed splendidly with three of my power amplifiers, both tubed and solid-state. Besides all this, it looks flat fantastic, a fancy piece of audio bling perched atop its own power pedestal.

If you’re in the market for a reference-level preamp, I heartily endorse auditioning the Signature IIa from VAC. It will take you a long time to exhaust its possibilities—it did me—and you may never find the end of them. That is, not until Kevin Hayes next cleans his astrolabe or peels an orange.

 

SPECS & PRICING

Number and type of inputs: Three unbalanced on RC A jacks, two balanced/unbalanced (selectable) on RC A/XLR jacks, one moving-magnet and one moving-coil phono input (with optional phono module); if no phono module, one additional line-input on RC A; one tape monitor, one unbalanced theater-bypass input
Number and type of outputs: Two RC A, two XLR, one RC A tape
Tube complement: Two 12AU7 and two 6DJ8 (linestage); six 12AX7 (phono)
Input impedance: 100k ohms
Output impedance: 96 ohms
Phono gain: 44dB (moving magnet), 64dB (moving coil)
Phono loading options: 470, 300, 250, 200, 150, and 100 ohms (mc); 47k, 30k, 25k, 15k, and 10k ohms (mm)
Audio chassis dimensions: 18" x 5.5" x 14.5" (plus knobs and connectors)
Power supply dimensions: 18" x 3.9" x 14.5" (plus connectors)
Weight: 20 lbs. (audio chassis); 23 lbs. (power supply)
Price: $15,500 as linestage, $19,500 with phono input

Comments

thotdoc -- Sun, 10/07/2012 - 23:43

Unless you are playing with your equipment every day, sticking with the tubes the manufacturer voiced the equipment with is your best option. Why do I believe this? I've used tube equipment since the 60's. Currently using Atmasphere MP1 and MA1s. One can become very lost when rolling tubes. B4 rolling tubes ask yourself, are you disciplined enough to always listen to EVERYTHING that has changed...not just the thing that changed...before making a decision about whether the change is better OVERALL? I can not tell you how often that sweeter sounding tube, or that tube that expanded the sound stage or gave me more details ALSO changed the sound in ways that were not so good....that I sought to fix by rolling more tubes in other places.

Hifimaniac -- Sat, 12/29/2012 - 23:22

I agree with the comment on sticking with stock tubes, especially with this particular preamp. Kevin Hayes designs his equipment around high quality, current production tubes and the sound is excellent. I have made subtle changes in my Signature IIa swapping out the stock 12AX7 tubes for the Psvane 12AX7s in the phono stage. They are manufactured in the same Shuguang factory in China but are manufactured to a higher standard and sound more musical; have a lower noise floor and longer decay than the stock tubes. By the way, this is a killer preamp. I replaced my Audio Research Reference 5 with this preamp and I couldn't be happier. The notes seem to have more body and three dimensiality to them. Bass extension is better and the soundstage superb. In my VAC Phi 200 monos I swapped out the two front input tubes, 6SN7's with Psvanes larger equivalent the CV-181. This subtle changes takes a really great amplifier to another sound level. Check out Psvane tubes as an alternative to NOS equivalents and give them at least 30-40 hours to settle in. You might even have some crackling the first 20 hours but it will go away.

Hifimaniac
Scottsdale, AZ 

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