After my review of the Aric Audio Transcend Series KT 120 SET (single-ended triode) amplifier, numerous readers asked me if there were any push-pull tube based amplifiers that could still provide the SET "magic"--the purity of timbres/tonality--and still provide enough power (at least 20 watts per channel) to drive their less efficient speakers. There are many fine sounding push-pull tube amps on the market today. However, they tend to have a slightly drier tonality than SET designs, along with not presenting as much "meat on the bone" imaging. I shared this with the CEO/Designer of Aric Audio, Aric Kimball, who informed me that he had just designed his new Transcend push-pull amplifier, which retails for $3,500, to be able to drive the great majority of speakers that listeners own and still provide much of the magic of the pure beauty of timbres of a SET amplifier.
I asked Kimball to provide an explanation of how he was able to achieve this design goal. "What typically separates push-pull from single-ended is that the design goals are seen as different," he told me. "In a single-ended, the goal is to shoot for as much transparency as possible with an ultra-simple and high-quality signal path, and as a bonus, that enjoyable second order harmonic magic that everyone loves shines through. Whereas with push-pull, most designers shoot for getting as much power as they can and focus on obtaining perfect balance from the phase splitter (the traffic cop directing in-phase and anti-phase signals to each of the push/pull power tubes).
"While on paper, playing this numbers game would seem to get you the best performing and sounding amp--much of the magic is lost. The tubes are pushed towards their cutoff point where they sound dry and lifeless (albeit with lots of power and bass). This is what many associate with sounding like solid state. In my Transcend and Special series push-pulls, I deliberately do not shoot for maximum power, or push the tubes to where they sound hard or strained. Instead I allow them room to breathe for a more organic and natural flow. As everything is playing closer to its sweet spot--the amp has a more graceful overload characteristic when driven hard (much like a SET). Maintaining the same simple yet high quality signal path that most designers would reserve for a SET gives these amps a single-ended sound signature (easy, natural transients with a robust midrange), but with more bass control, slam, and power than a single-ended can deliver."
The Transcend push-pull amplifier runs in Class-A operation and uses three 6SN7 tubes and two pairs of EL-34, KT-88, or KT-120 power tubes. The amplifier's auto-bias feature means you never to have manually adjust the power tubes. The Transcend can be run either in Triode or Ultra-Linear Mode. I strongly preferred the amplifier in the triode mode where the power ratings were: EL-34=20 watts/KT-88=25/KT-120=40 watts. If you set it into ultra-linear the amplifier roughly doubles the above-mentioned power into both channels.
Another feature is adjustable negative feedback to fine tune the sound to your personal taste. My favorite setting was using EL-34 power tubes with no negative feedback. Finally, there is a volume control that allows you to directly run the amplifier from your source if you want to by-pass using a preamplifier.
The amp measures 8 inches high, 18.5 inches wide, 13.5 inches deep, and it weighs 39 pounds. It is set up in the classic style of tube amplifiers, in that that the three massive Hammond transformers are on the back of the top plate of the chassis with the driver and power tubes situated in front. The toggle switches to change from triode to ultra-linear mode are located between the power tubes. On the front plate you'll find the on/off power switch, an engraved Aric Audio name plate, the volume control, and the negative feedback control dial. Around back you find one pair of RCA inputs, two sets of 4/8 ohm speaker wire outputs, and the IEC port. The craftsmanship of this handmade amplifier is easy to see in its stellar appearance and the quality of parts that are used.
Aric Audio ships their gear in very stout packaging with internal bracing and soft fillers, so the amplifier arrived in perfect condition. For the duration of this review, I mated the Transcend with the Micro-ZOTL preamplifier. The rest of the upstream equipment was comprised of a CEC-3 CD transport, Lab-12 reference DAC, Running Springs Dmitri power conditioner, MG Cable reference silver and copper wiring, Audio Archon power cords, all placed on the Tomo rack/footers by Krolo Design. For speakers I relied on the Tekton Ulfberht and Double Impact monitor.
My first selection was jazz tenor saxophonist James Moody's CD Timeless Aura (Vanguard), which allows me to center on the tone of his horn to see how well an amplifier will reproduce the unique timbres accurately captured on this fine recording. The Transcend had the grit, bite, and colors of Moody's saxophone all on very pristine display. It delivered that special tonal quality that SET amplifiers are loved for without any attenuation/distortion when either volume levels where at high DB levels or powerful macro-dynamics appeared on the recording.
The next selection was the CD by vibes player Joe Locke, Lay Down Your Heart Blues & Ballads Vol. 1 (Motema Music). This collection of music was very well recorded in a studio setting, and the clarity of its overall sonics reveals tiny micro-details, particularly on the decay of the notes from both the vibes and the cymbals. These decays and minute aspects of these instruments were easily and clearly heard. The Transcend push-pull recreated the sound of the recording studio space with excellent placement and layering of where each band member was located.
I wanted to test the abilities of the Transcend when it had to drive my system at higher volumes with music filled with rough edges and powerful bass extension. I put my hometown Chicago blues guitarist Buddy Guy's CD Slippin In (Silvertone), raised the volume to live listening levels, and cued the song "Someone Else is Steppin' In (Slippin' Out, Slippin' In)." This cut not only features the searing sound of Guy's guitar, but also the deep powerful notes of Hammond B-3 player Reese Wynans. The gut-pounding organ bass notes and the intense raspy notes coming from Buddy's electric guitar were rendered realistically and dynamically. This amp can kick-ass on blues or pop music when that's the music of choice.
For my last selection, I choose one of my favorite jazz recordings on CD: Lester Young's Lester Young with the Oscar Peterson Trio (Verve Master Edition). I have heard this album of classic swing music on many different systems through the years. If an amplifier gets the very special and different timbres and tonality of Young's tenor saxophone correctly it is a beautiful and emotional music experience. The Transcend amplifier was able to provide this emotional experience in my system. To get this rendering of purity of timbres/tonality you normally have to use a SET amplifier. However, this push-pull design was able to get to this inner beauty of tone while delivering the overall macrodynamics and bass extension usually lacking in a flea-watt SET design.
Like all tube-based amplifiers, you will have to re-tube sometime in the future. However, the tubes that sound great in this amplifier are rather inexpensive current stock tubes that are very easily purchased on today's market.
This amp runs hot with exposed power tubes (no tube cage); therefore, it could be a hazard if small children or pets are part of your household. You simply must have enough room to air this amp out while not placing it anywhere where anyone can easily access the hot bits.
Aric Audio is a limited distribution product compared to other audiophile tube brands.
Competition and Comparison
Two tube-based amplifiers that I have had extensive experience with that, based on price and power ratings, would be competitors with the Aric Audio Transcend would be the PrimaLuna DiaLogue Premium Stereo amplifier, which retails for $3,899, and the McIntosh MC275, which retails for $5,500. Each of these amplifiers has the virtues of extended bass, enough power to drive many different types of speakers, relatively good transparency, and above average soundstaging capabilities.
The Transcend push-pull amplifier matches both amplifiers in terms of bass extension and control, as well as current output. It significantly outperforms them when it comes to timbres/tonality. The PrimaLuna DiaLogue Premium and the McIntosh MC275 both sound noticeably dry and somewhat washed out overall compared to the rich colors of the Aric Audio amplifier. Both the PrimaLuna and McIntosh also lack the effortless liquidity that you experience with the Transcend.
After an extensive evaluation, my conclusion is that Aric was able to live up to his design goals of creating a push-pull design that would have the wonderful virtues of SET amplifiers. These include extremely dense and natural timbres, often referred to as a type of inner glow, along with very three-dimensional imaging, but have enough balls regarding wattage/current to drive many more listener's speakers.
I have historically found many push-pull tube amplifiers to be rather solid state in their presentation. Nothing wrong with that, but if you're going to go that route, why not just go with a great no maintenance solid-state amplifier (Pass Labs)? However, if you want the unique liquidity and beautiful timbres/tonality, along with meat on the bones imaging of a SET design, you still have to turn to tube designs. This is where the Aric Audio Transcend push-pull amplifier comes into play. It offers most of the virtues of a SET flea-watt design with the current to drive much more demanding speakers.