Audio Research Reference 600 Power Amps Reviewed

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What's unusual about the Reference 1 is a ruse employed to prevent technofear. ARC rightly presupposes that its customers are used to rotary controls and may even prefer them, in the way that car manufacturers still haven't succeeded in convincing drivers who actually use their gauges that digital read-outs are better than analogue ones. So the '1 wears knobs, only they don't rotate. They're spring-loaded, self-centring intermittent types, like the ones on the Copland CD player and the Acurus ACT1 processor/pre-amp. They have small arcs of activity, and you jerk 'em left or right to raise or lower the volume, alter the balance or select sources. Hold them and they pan through the entire arc which surrounds them in the form of green LEDs. Invariably, you'll spend more time using the remote control, which provides every single function bar the choice between balanced and unbalanced input selection. And I must say that, as the remote arrived only the day before I had to surrender the system, you do get used to these intermittent controls very quickly.

Across the front, the '1 wears its gain, balance, record out and source selectors as the aforementioned faux-rotaries. In a channel below are press-press toggles with the same feel as the knobs. They always self-centre, so you push them up or down to choose on/off, balanced or single-ended input, normal or inverted polarity and mute/operate. Green LEDs all over the place tell you what mode you've chosen.

Is there a more jam-packed rear panel than the one on the Reference 1? Across the top are the right-hand phono and XLR inputs; across the bottom, the left-hand channel's inputs. In addition to these eight sets are three pairs of outputs, one for record and two for main, also in XLR and phono form. Lastly, there are easily accessible fuses, and ARC still uses captive mains leads. (Note that these products were the first I've used in '96 with the CE marks.)

Inquisitive readers might wonder how a pre-amp can weigh 30lb. Like the '600, this wears a 3/8in thick aluminium front panel. Inside are the eight Sovtek 6922 dual triodes, chosen for their reliability, while tube regulation is solid-state for maximum silence, via a combination of MOSFETs and JFETs. Part of the weight is also due to the inclusion of three separate toroidal power supplies, one each for DC regulation, high voltages and the digital section. Discrete components are used throughout, the Ref 1 being an IC-Free Zone.

Although only 21 LEDs surround the volume control, there are plenty of steps inbetween...in excess of 156 according to Bill, at 0.3dB per step. You'll soon develop the right flick of the wrist for turning the switch just enough to activate a single step. And you hold it for continuous adjustment. Simple. The balance control operates in an identical manner. Switch-on is accompanied by a 45 second delay, and Audio Research recommends lowering the volume even when you're using mute when changing sources.

Spec-wise, you're going to think I accidentally misplaced the sheet and picked up one from a tranny pre-amp. The frequency response is +/-0.5dB from 1Hz to 200kHz, with -3dB points at 0.3Hz and better than 400kHz. Distortion? Less than 0.01 percent at 2V RMS output. Gain is 12.3dB balanced, 6.3dB unbalanced, tape output is 0dB, and the input impedances are 220k ohm balanced and 110k ohms unbalanced. The output impedance is 400 ohms balanced, 200 ohms unbalanced, and maximum output is 7.0V RMS, or 3.5V RMS single-ended.

As the amplifier arrived long before the pre-amp, I had a chance to use it with a number of respected control units, but I shan't embarrass them: more than once I was told that I wouldn't know what these amplifiers could do until I heard them with the Reference 1 pre-amp, and these harbingers of bliss were right. And while I also tried the Reference 1 with other power amplifiers, I have every reason to believe that these items will sell in tandem; they're just so perfectly matched, as you'd expect of components designed to work together from the outset.

With products so close to perfect, so commanding, so coherent and so blatantly superior to anything else on the planet, it seems daft to break down the performance into those little categories which determine our priorities. So it is with a great sense of inconsistency that I, known as I am to be ambivalent about bass as a priority, must point you to the lower octave brilliance of this system. Consider that I have been using Wilson's System V ever since it was launched, that I know my room pretty well, and that I returned to the usual source material. The CD player of choice was the Marantz CD-12/DA-12 in balanced mode. Wires were courtesy Harmonix for the speaker connections and Mandrake balanced for the rest - all familiar stuff.

And still I never knew just how much low-end information there was from the piano behind Lou Rawls on At Last, how much more bottom octave activity could be wrested from Willy DeVille's 'Assassin of Love'. More impressive still was the weight added to otherwise bass-free sessions like the a cappella of Bobby McFerrin or the Persuasions. Remember: I'm simply cannot be bothered with gut-churning, plaster-cracking macho-bullshit bass. I find it neither pleasing nor necessary. And yet here was a system which, while not changing my allegiance to the importance of the midband over all else, showed me what sins a component can commit in the sub-60Hz sector. So, no, I didn't spend too much time with my cherished LS3/5As in tandem with the Audio Research package. But I did rediscover a whole lot of material which I thought the Wilsons were being fed intact.

It's not dry, mechanical bass, as is the fruit of much lesser solid-state equipment. Rather, the Reference 600/Reference 1 combination emulates with ease the kind of bottom octave action many presume to be the sole preserve of the better solid-state amplifiers. It's bass without restrictions. Extension, quantity, speed, palpability, 'tunefulness' (gawd, I hate that word...) - pick a trait and I guarantee you that this system excels with it. More delightful still, and part of their overall supremacy as a purveyor of 3D images, is the way the Reference components prove that low frequency information is directional. Elder jazz recordings with unplugged bass were revealed to be so rich with localised bass sounds that I cannot imagine even the most venal of centre subwoofer vendors continuing to argue that bass is non-directional at best.

But the midband... How on earth do you juggle such clarity with so much warmth? A natural acoustic with almost heightened precision? When Editor Harris arrived for a brief listen (coward that I am, I refused to write the review until he confirmed my findings), I condensed the session by playing vocals of a highly textured nature. And SH knows the sound of Rawls, as well as the brilliant counterpoint of Dianne Reeves. Think of a juxtaposition that's better: Rawls' voice so lived-in that it makes Joe Cocker sound like McCauley Culkin, Reeves' voice so sweet, clear and pure that you worry about the absence of texture. And yet their duet on 'At Last' showed how two utterly disparate sounds can blend yet remain distinct, how a truly transparent, coherent system can handle both simultaneously, even when there's a minimum of ancillary instrumentation to cover up any minor cracks.

For vocal range, I played some Howard Tate, the remastered sessions released by Polydor in the USA as Get It While You Can. And SH finally understood why I rate Howard Tate as the only vocalist fit to follow Jackie Wilson. Better still, the sessions were mid-to-late Sixties East Coast recordings, where the studio musicians knew that rhythm was the antithesis of birth control. Sexy? You ain't never heard deep soul until you hear the way that the References plumb those depths. Emotional depths, way down past gut level, right to the core. I haven't been so moved by the sheer presence of music in my home since the first time I heard that Tate album, when the music had to transcend the system on which it was played.

At the risk of annoying my family and neighbours, I did rock out on occasion. I sampled Led Zeppelin in all its glory, got dusty with ZZ Top, trashed my imaginary Les Paul to Jeff Beck. I felt like a kid all over again, discovering hi-fi for the first time, even digging out the recordings which, back in '68, christened my first-ever system. And tried not to think about how much 9,900 and 32,000 equal...

Bill Johnson should retire. He has nothing left to prove because the Reference 1 pre-amp and Reference 600 power amps are, as far as I'm concerned, the finest audio amplification devices ever produced. Read my lips: the very best sound I've ever heard from a hi-fi system in my entire 43 years on the planet.

Now it's up to everyone else to take it from here.

Additional Resources
• Read more stereo amplifier reviews on HomeTheaterReview.com.
• Find an AV receiver to pair with this amplifier.

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HTR Product Rating for Audio Research Reference 600 Power Amps

Criteria Rating

Performance

5

Value

4.5

Overall

5

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