Art Audio Gill Signature Amplifier
Mighty powerful single-ended amplification!
Review By Todd Warnke
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  Most single-ended amps start the game with two strikes. First, the nature of the circuit as well as the tubes most commonly employed therein result in low single digit power, and that means that the average audio-adventurer has to significantly reconfigure their system before sampling SET sound. And second, even if you end up liking what you hear, re-tubing with those esoteric NOS tubes, or even with many of the current production tube types such as the 300B, is a real budget-breaker. The fact that the Art Audio Gill Signature amp squarely addresses those two issues is the first thing that caught my attention when Joe Fratus of Art Audio talked to me about his new amp. With 15 watts of power, and as long as you have fairly sensible speakers placed in a fairly sensible room, the Gill Signature has enough pop to get you SET sound without having to throw your current speakers away. And second, by using EL34 output tubes, re-tubing the entire amp costs less than the price of a single Western Electric 300B. 'Course, we all know that the significance of an amp is not in the design spec nor the rated output but in the listening. So when Joe offered to send the Gill Signature out to the wilds of Colorado, I eagerly accepted.

History Class
Art Audio, while fairly young has built quite an enviable reputation, based primarily on their single-ended designs such as the Jota and the PX-25, although the company has always had push-pull and EL34 based designs as well. As such, the integration of single-ended and the EL34 was inevitable.

At $3,800, the Gill Signature is the most affordable amp in the Art Audio stable, but like the others is still built to a superb level and fit and finish. The casework is finished in a luxurious black paint. The transformers, which run in a row across the back of the amp, are covered with a single case, which is topped off with a chrome plate. The front fascia also sports a chrome plate with a subtle blue power light. Round back are a pair of high-quality input jacks, one situated on each corner of the unit allowing for your choice of interconnects, and 2 pair of Cardas binding posts, also separated so that you can use any speaker cables I know of without getting too bunched up.

The insides are built to equal standards, with extensive use of Hovland and Axon capacitors and Roderstein resistors, separate polypropylene filter capacitors for each tube section and ceramic tube sockets and silver Teflon wiring. The tubes stand out for all to see, which I like. The input/driver tube is an NOS 6SL7 while rectification is courtesy of a 5V4. Power is supplied by a pair of Valve Art EL34B tubes per channel. Lastly, for an additional $200 the factory can add a front panel, passive volume control, something that Art Audio offers across their line. I know a good many folks who have tried the passive volume control in other amps and feel that as long as you have enough gain in your system that you would need to budget of at least $3000 for an active pre-amp to beat the quality of the passive Art Audio design.

The Sound Of An EL34 Pushing And Not Pulling
The Gill Signature occupies a rarely inhabited land between push-pull pentode and single-ended triode design. Using the pentode EL34 but placing it triode operation will certainly offend many of those in the SET old guard. But wiring the EL34 up in a single-ended configuration and thus reducing the power output of a pair of tubes from somewhere around 40 watts to 15 will equally offend push-pull stalwarts. Of course this simply means that each camp is listening with preconceptions and not with their ears. We, being of sterner stuff will cast aside preconceptions and just listen. And, fortunately, the Gill Signature makes listening very pleasurable.

The first part of that pleasure comes from the way the new Art Audio amp handles harmonic information. As opposed to my brother-in-law, who is annoyingly dense, the Gill Signature was gloriously dense, at least in the harmonic sense. With this amp it's not merely the breadth of harmonics from saxes, vocals and pianos that is captivating, but it is also the weight of each step in the harmonic envelope that is portrayed with superb fidelity.

I'm a really horrible amateur piano player, but I have the opportunity to play a wonderful instrument. My piano teacher has a dedicated studio with a lovely baby grand that I abuse with regularity. Still, in spite of my ham-handed, off beat frightening of that instrument it establishes a reference point that is simply beyond the reach of every system I have tried at home. Sure, some get closer to the ideal than others, but I have yet to hear a system that truly captures the harmonic density along with the separation of individual notes and the awesome dynamics of the piano. The Gill Signature didn't get their either, but to its credit, as well as my gratitude, the Art Audio amp, with both the Soliloquy 6.2 and Merlin VSM-SE speakers, got the first two parts, harmonics and separation, right in a way I have never heard before. With a recording such as the Jacques Loussier Trio playing Satie [Telarc CD-83431], I could relate to the sonority of the piano as more than something captured on tape, and yet each note was distinct. With the Gill Signature and by virtue of its amazing harmonic structure this recording stopped being a recording and became a living thing that occupied real space and was played by real people.

Part and parcel of the harmonic beauty of the Gill Signature is the way it handles details. Rather than thrusting sonic information at me in a aural-pornographic bump and grind, the Art Audio laid down details with the delicate touch of a lover. For example, on the Loussier recording, unlike many amps that project certain frequencies into the room and away from their source, each note of the piano emanated from the same plane but with distinct detail and presence. This trait, combined with the harmonic richness of the amp, gave the Gill a laid-back but inviting character, drawing me forward into the musical moment rather than forcing the performers off the stage and into a lap dance.

Further still, details were in complete harmony with the level of clarity of the amp so that music heard through it seemed complete and organic. Put another way, when listening with the Gill Signature I never felt that what I was listening to was but a part of the recording - nor that the amp was obscuring details that would occasionally peek through the veil. This is not to call the amp perfect in terms of clarity as I have certainly heard amps that peer slightly deeper into recordings, rather it is to say that the scaling between detail, clarity and presentation was in complete harmony. An example - the level of clarity and detail richly rewarded tube rolling. I started with the stock Valve Art power tubes but also tried Sovtek, Svetlana and EH EL34 tubes, and was easily able to hear the differences in each, but the amp also allowed me to enjoy the strengths of each power tube. So the better bass of the Valve Art, which came with a loss of midrange richness as compared to the Svetlana, was a change of pace without ever becoming a penalty. 

Dropping back into more standard audiogeek descriptions, the Gill Signature has a broad and fairly accurate tonal response. As with most EL34 amps, you give up some of the bottom octave (although the standard Valve Art E34L tubes surprised me with how deep they went, as in this area they easily out pointed the EH, Svetlana and Sovteks) but you also get that wonderful EL34 mid and upper bass. A note to prospective owners, the amp can use either the 5V4 or a 274B as a rectifier. Joe Fratus shipped me the amp with a 5V4 but later sent along a Valve Art 274B for comparison. With the 274B bass extended a bit deeper had tighter articulation. Not that the 5V4 was bad, as it wasn't, with a speaker that had nice extension on its own but was slightly bass heavy, it would be a perfect match. Still, with most audiophile speakers I imagine that the 274B would be the better choice. Of course, one of the joys of tubes is that you get to roll it your own way.

Going up top, the treble range was very even and extended but not at all bright. One of my all-time favorite ambient disks is the live, 1996 Biosphere/Higher Intelligence Agency album, Polar Sequences [Beyond Records RBADCD17], recorded at the annual Tromso Norway Music Festival. It opens with the sounds of festival attendees riding the gondola from the town center up the mountain to see the show. The mechanized sound of the lift is used to create a very long and slow rhythm but the track also includes high frequency clanks and creaks. A great many amps over-emphasize these high frequency sounds and so create the sensation of a gondola on the verge of falling apart. The Art Audio didn't, instead it got it perfect. How do I know? While I've never been to the Tromso festival (something I hope to rectify soon), I am a long-time Colorado resident with years of familiarity with the gondolas at Vail, Keystone and Winter Park. And this amp nails it. When listening to this track, except for the wafting scent of unwashed 'Boarders, I was in a gondola.

As for the mids, they were, in a word, glorious. I have previously documented my not so secret and not so pure infatuation with Joni Mitchell. Part of that lust comes from the sound of her voice, child-like but knowing when young, and traveled but still hopeful when older. With the Gill Signature I found several new details to luxuriate in. Another, and altogether different female voice I love is Me'Shell Ndegeocello's. With the Art Audio in the system the depth of her voice was readily apparent. On Ecclesiastes: Free My Heart from the Peace Beyond Passion album [Maverick 46033-2] when she sings "Free my heart so my soul can fly, free my mind of my worldly wants and desires … take my hand, come and take my hand", I had chills running down my spine, and was eager to take her up on the offer.

All right, if you got this far you're thinking, "great as far it goes, but just another SET tone machine", and that's my fault as I have so far burned a few kilowatts on the tonal and harmonic characteristics of the Gill Signature. But there is more here.

Dynamics have nice, if not bone-crushing weight. Ndegeocello's remake of the Bill Withers' tune, Who is He and What is He to You, is a real bass workout, both in terms of extension and dynamics. The Art Audio amp, while not in the category of the Atma-Sphere MP-3 mk. II which sets the tube amp reference for dynamics around here, did far better with this track than I expected as the impact of the lower octaves was tuneful, powerful and certainly danceable.

With large scale classical pieces like Bruckner's 8th symphony (for reasons not even a therapist could divine I occasionally sit down and play my 3 favorite version of this piece back to back - Karajan with the VPO, the Tintner recording on Naxos, and Celibidache with the Munich Philharmonic) I was impressed by sense of size and power the Art Audio conjured. An amp like the admittedly far more powerful Rowland Model 112 that passed through here a while ago was better able to convey the very bottom of the orchestra, but gave up quite a bit to the Art Audio through the mids and treble, enough so that I preferred the Gill Signature as a late romantic classical music amp to the pricier Rowland.

Finally, this amp stages superbly. Width, breadth and height (when the recording has it) is never oversized, but also never shorted.

All right, time for the debit side of the ledger. As I've alluded to several times, the bass, while full of wonderful tone and mid-bass kick, would still not be the first choice to power your next rave. And while the amp carefully and beautifully balances clarity, detail and harmonics, other amps I've heard extract more detail from recordings. Finally, 15 watts, even watts this good, will not work in every situation. Short list, but then the Art Audio really is that good.

The Obligatory Comparo
$3,800 will buy you a lot of amps, and I happen to own of them, my long-term reference, the hybrid, solid-state output device, single-ended Blue Circle BC6 which retails for $3,750. With 25 watts a channel it is a natural choice to place up against the Gill Signature. Comparing the two, the Art Audio has the edge in harmonic richness while the Blue Circle has greater clarity and slightly better dynamics. Both give music a natural breath with the Art Audio emphasizing textures and the Blue Circle rhythms. Each stages very well, although the Gill Signature give players a tad more body and the BC6 a bit more specificity. Finally, the Art Audio is slightly laid-back and the Blue Circle ever so slightly forward. Overall, both amps work well in similar situations - mid sized rooms, and with speakers of mid and higher efficiency - with the Blue Circle able to drive slightly more difficult loads and the Art Audio offering a greater variety of options to tailor the amp to your particular tastes.

The Long Goodbye
I am extremely impressed by the Gill Signature as Art Audio has done a canny job of addressing the issues most audiophiles will have in coming to single-ended triodes for the first time, or the last time for that matter. With a broad variety and endless supply of affordable power tubes to play with, you can roll tubes to your heart's content. Nor do you have to save the amp for the annual playing of the 6-eye pressing of Kind of Blue, as you can use it all day, everyday. Secondly, the Gill Signature has enough power to use in real listening rooms driving real speakers. Best of all, neither of these virtues come with a concomitant loss detail, harmonic power, refinement or musical enjoyment. If you opt for the optional passive volume control, $4000 gets you a single input integrated with amazing sound for next to nothing in audiogeek dollars. So, an SET for everyone then. And one I feel everyone needs to hear.

Specifications

Type: Single-ended triode amplifier

Tubes: Four Valve Art EL34B output tubes 
          NOS 6SL7 for input/driver duties
          5V4 for rectification

Power Output:15 watts per channel, to channels

Input Impedance: 200K ohm.

Sensitivity: 1.25 volts for full output 

High quality binding posts and input jacks

Standard 8 ohm tap with optional 4 ohm selectable

Parts: Hovland and Axon capacitors
         Roderstein resistors.

Tube and solid state rectified high voltage supply w/ Hexfred Diodes. Separate Polypropylene filter capacitors for each tube section. Ceramic tube sockets and silver wiring

Optional front panel volume control ($200)

Price: $3,800

Company Information
Art Audio
34 Briarwood Road
Cranston, Rhode Island 02920

Voice: (401) 826-8286
E-mail: vze572mh@verizon.net 
Website: www.artaudio.com