In the immortal words of Notting Hill's Rhys Ifans, only "a daft prick" would expect a high-powered push/pull amplifier to sound like a micro-powered SET. On occasion however, a leading man daft prick -- like Hugh Grant in the same movie -- does conquer the odds in the end to walk away with the coveted prize. In the real world of High-End audio, I got to wear Hugh's role for size. Little did I know that I'd enjoy equally smashing results (minus the movie star salary of course - writers live word to mouth).


With a familiar track from his k.d Lang album, Michael Elliott took the pulse of the resident system around my 6wpc Art Audio PX-25. He then listened to it via the Aria amp and repeated the process once more for aural verification. He acknowledged that by comparison, the second rendition did obscure some inner detail, subdued the ebb and flow of microdynamic agility and consequently didn't quite offer the same immediacy.


Michael's first action would demonstrate the effects of swapping the two expensive coupling capacitors for two which his specialty vendor had just released. They precisely duplicate the electrical values of the originals and thus measure identically. With the help of senior tech and soldering ace Dai, the new caps were installed (see red cap floating on unclipped leads between tube and upright black cap).

The differences were not subtle. The new cap (since standard issue in all XL production models) was clearly more refined and smoother yet also offered more detail. This was my isolated brush against the dance of parts substitution which electronics designers undergo in their exhaustive voicing process of products. Now the real demonstration of the variable tuning could begin, centered around the predriver's idle current and output stage bias .


The team unbolted the front grate and one of the sides and popped the cover and rear panel. Elliott then played math whiz on his calculator. He had decided to shift the tonal center of his amp subtly downwards. He would decrease the operating values of his eight emitter resistors in the Class A predriver stage to raise its quiescent current. He approximated a 20% offset to be a good starting point. He calculated the corresponding values for the piggybacked parallel resistors Dai would fish from the well-stocked traveling tool box to install momentarily.

With the nonchalant precision of a Black belt solder surgeon, Daii operated in what seemed rather crammed quarters of the tightly populated circuit board. He worked in record time and without missteps or "overdubs" on my kitchen's butcher block cart.
Michael then confirmed his handiwork under a magnifying glass. The patient was alive and kicking and close to ready for round II.

Before we could resume listening, a matching reduction to the bias current in the output stage had to be made. Out came the voltmeters and a Variac. After the requisite settling period of the heatsink temperature, the corrected value was affirmed and locked in via trim pots. The eagerly anticipated follow-up listening session could commence. I had no idea what to expect but remembered Rhys Ifans' scene-stealing character.

At this juncture, it seems important to stress that these two adjustments were complementary to retain the circuit's innate balance. Elliott increased the idle current of the predriver stage and reduced the bias of the output stage. Apparently none of these changes result in any measurable frequency response variations. Audible changes would live in the realm of "you might hear it but you won't be able to prove it on paper".


Hot damn & vanilla ice-cream with tart cherries! The minor thickness and oversaturation had now evaporated. The aural landscape was recognizably the same, but the lighting had shifted. I could now clearly see between and around the performers to experience the space they were performing in. The subtle grit that hovered like dust motes between the artists and somewhat interfered with their outlines was gone. Put differently, the textural weave had expanded for more spaciousness. This released the concomitant aroma of musical relaxation coupled to keener resolution.


Simultaneously, the sense of presence was strongly heightened. The drama of immediacy had been enhanced to accentuate what I call communicativeness - when the music reaches out across space to come to you. Though Elliott had indicated a small timbral downshift, I clearly heard added lucidity in the piano's decay trails even in the upper registers. What was going on?

Only after listening to the phenomenal French double bassist Renaud Garcia-Fons was I certain that Elliott had indeed shifted the timbral balance downwards - the Jacob's ladder of upper harmonics inside the blossoming bass notes didn't extend quite as high. Perplexingly though, rather than sounding darker, the amp clearly exhibited more openness.

While there probably was slightly reduced perceived HF energy, this apparent reduction acted as though a certain hash or high-frequency dither had been removed to deepen the blackness between and around the notes. Michael and I compared observations. Though we used different terminology to describe what we heard, it was clear that we not only both perceived the same phenomena but, in this particular system context, clearly preferred the post-op results.


Had I been a paying client -- or belligerent reviewer unawares of the travel fatigue both gents were exhibiting by now -- I would have pressed for additional adjustments.

Would a further movement in the same direction by, say another 10%, have elicited ongoing improvements? Or would it have worked backwards? And what, for curiosity's sake, would moving in the opposite direction past the starting point accomplish?

But I had heard enough: Michael Elliott's claim -- of knowing how to adjust the amp's voicing in concert with its prospective owner's room, system and listener preferences -- was a simple yet astounding and fascinating matter-of-fact statement. Scary how far I had already walked down the road to perdition (all is well in hell). Allowing perfectly valid observations -- about the initial amplifier's "sound" or "sonic signature" -- to fossilize into fixed conclusions about push/pull flavor, I had nearly performed character assassination - the reviewer as audio hit man.


Granted, the amp still didn't sound exactly like a low-power SET. But how daft of a prick did I really have to be? In one single exploratory shift, Michael Elliott had transformed the Aria's gestalt into the intrinsic flavor of my micro-power triode reference.


The Aria's bass, expectedly, was still more weighty. It still exhibited more across-the-board textural meatiness versus what by comparison could also be called a minor leanness of the PX-25. But, fundamentally, both amps now illuminated the aural landscape from the same time of day, separated by degrees only, perhaps within the span of less than an hour.


I now felt convinced that, within the reasonable restraints of the circuit's core signature, this amp truly could be expertly tuned just like a musical instrument. It makes it somewhat trying to concoct a neat and unambiguous concluding statement - save to say that the WT100 can sound very much like an excellent high-power push-pull tube amplifier, but also like a zero feedback SET with massive cojones. That is to say (and no matter which), distinctly tube, not transistor. Uniquely, it also offers the significant and very real advantages of bass control, raw drive and load invariance of the latter.

Hugh Grant, disheveled, out of time and prepared to utterly humiliate himself in front of Britain's most distinguished press, finally utters the self-directed condemnation of his roommate-from-hell in public. Julia Roberts leans to her producer who asks one of the journalists to repeat his prior question.


Is the premium LX version of the Aria WT100 worth the not insubstantial surcharge over the base version? (You didn't know Julia was an audiophile?)


Are you the kind of listener who appreciates the severity of synergy with its myriad effects on a system? Are you shopping in the price range of this amplifier or above and recognize that once a core circuit has been established, taking it from good to truly great does take that disproportionate effort of superior but costly parts?


Are you convinced that tubes handle certain musically vital affairs in ways solid state cannot? Do you -- or intend to -- own speakers that aren't simpatico with traditional tube amps? Do you further abhor even the off-chance notion of arcing power tubes? Do you consider such an amplifier purchase a long-term investment that should adapt to future changes of location and ancillary components?


If so, what other options can you think of? (And remember, the "same" amp can be had for $8,800 pre-voiced. If you trust your ability to predict the amp's interaction with your components. If you can successfully express your sonic preferences such that Michael Elliott understands them exactly as you mean them - potentially more challenging than apparent.)


To be frank, I currently know of only one other amp that offers this unique combination of virtues and adaptability, costs the same but outputs less power - the AUDIOPAX 88 monoblocks.


Add Aria's designer-backed on-site service and lifetime warranty. Does that answer our journalist friend's question to your satisfaction?


I look back at the Aria WT 100LS XL amplifier as a notion-bustin', mind-expanding, rewrite-the-rules encounter. Were I not already SET for state-of-the-art amplification, I would give this piece very serious personal consideration indeed!

Both Aria and AUDIOPAX amplifiers accomplish their tunable voicing by altering their bias current. The former requires parts swapping by the designer, the latter is deliberately user-adjustable. Both designers confirm that these sonic changes do not affect measurable frequency response but operate in the timbral domain of harmonics. I recall a review of Herron Audio's solid state amplifiers who had been mistakenly delivered with miscalibrated bias current. Once rectified, the reviewer was shocked at the extent of the sonic improvements. Owners of tube amps with user-adjustable bias already know about these effects.


This seems to indicate that an amplifier's bias current acts as the fulcrum or balance point of its final timbre. The traditional solution is to set it permanently. But if Michael Elliott's and Eduardo de Lima's precedents are any indication, we should be seeing future designs that take into account the variability of the amp/speaker interface and listener bias. I predict they'll offer -- within preset parameters -- provisions to shift the amp's harmonic distortion envelope along this fulcrum of quiescent predriver charge or output stage bias. Based on my personal experience, this would certainly appear to be the next logical step of optimizing in-room amplifier performance and long-term listener satisfaction.


Kudos to Michael Elliott for leading the charge with a (semi) transistorized amplifier!

Our deepest thanks to Srajan for taking the time to review the Aria WT100LSXL power amplifier. Ever since these amplifiers were introduced, we've received overwhelming response. Partially due to the excellent sound that listeners have enjoyed. Partially due to the great value that these amps represent. Partially due to the lifetime warranty . . . and I can't help but think that it is also somewhat due to the fact that the customer can deal directly with the designer (me). Each WT XL amplifier is built individually to the customer's requirements. As is illustrated by Srajan's experience where we were able to re-voice the amplifier to provide the SET sound he prefer, it is voiced to meet the sonic preferences of the listener.


I have come to appreciate that most customers who have learned to trust their ears recognize that there is no such thing as absolute accuracy. They realize that electrically-reproduced music does not sound like the real thing. These customers have developed a sense of what works for them sonically. And not everyone agrees. Some like a quick, detailed, fast sound with lots of "sparkle". Others respond to a warm, round, sweet sound. The extraordinary flexibility of the WT amplifiers -- not only in terms of the ease whereby they drive the most difficult speakers, but also in how the sound can be tailored to meet the needs of the customer -- shows that it is possible to get any sound quality desired without sacrificing power or reliability.

(Well, I better qualify that last statement: it's possible to get just about any sound quality you like as long as you like what tubes do. It's no more possible to get a WT amp to sound like a transistor amp than it is to get a transistor amp to sound like a tube amp. That said, within the palette achievable by a good tube amp, you can get what you want with the WT amps.)


What we did at Srajan's in one evening is something we generally try to allow a full day for. We gave Srajan the "reviewer quickie tour," designed to demonstrate the amplifier's capabilities. We normally set aside three days for a client voicing: two days for travel and one for voicing. But voicing is not reserved for customers who purchase the premium XL versions alone: the introductory non-XL amplifiers can be voiced at the factory before shipping if the client wishes to have non-baseline voicing pre-installed. WT amps can be revoiced at a later date at the factory for $280 (plus shipping); and onsite voicings can be arranged.


The development of these amplifiers would not have been possible without the encouragment and support of all the people who have contacted me for upgrades on their Counterpoint equipment, and have offered advice and feedback on the upgrades for the SA series of power amplifiers. It was during these upgrades that the WT technology was refined to the present state: A hybrid power amp that does not sound like the worst of both worlds (the soft treble and bass of tubes combined with the grain and edge of transistors) but the best of both worlds - providing the magic sonics of tubes along with the bass drive and speed of transistors.


Michael Elliott
President, Aria Ltd.