Audio Research Reference 6 line preamplifier Page 2

That may offend the sensibilities of those purists who demand absolute accuracy, but in audio, there's really no such thing. Nonetheless, at the very least, a preamplifier should be wideband, linear, and produce low amounts of distortion and noise.

But can everything be measured? The months I spent enjoying the Audio Research Reference 6 told me that what William Z. Johnson said in 1994 holds true today. As I write this, I have no idea how the Reference 6 has performed on John Atkinson's test bench, though its published specifications indicate: an exceptionally wide frequency response of 0.4Hz–200kHz, +0/–3dB, in balanced mode at rated output into 200k ohms; distortion of <0.01% at 2V RMS, balanced output; and crosstalk measuring –88dB or better at 1 and 10kHz.


What I do know is that after I'd installed the Reference 6, late on a hot August evening, that first night of listening produced intense surprises that I'm sure can't be measured. Record after record, I found that the Reference 6 greatly increased my understanding of very familiar recordings, seeming to enhance the intentions of the musicians, even when their sounds were generated electronically.

I'd begun my listening thinking I'd be evaluating the differences between my reference preamplifier, the darTZeel NHB-18NS, and the Reference 6 in terms of the usual frequency response, soundstaging, tonality, and so on. But those took a back seat to the ARC's ability to let me lock on to and follow rhythmic and instrumental paths that had previously been blocked or lost in the sonic shuffle, as well as hear fleshed-out strings from recordings that had previously sounded somewhat thin. Far from fulfilling the tube-gear clichés of "glorious midrange, no bottom-end grunt," the Reference 6 packed a surprisingly solid bottom-end wallop, topped off by grab-and-hold grip. Not what I'd expected.

The first album I played was Eno's Another Green World (UK LP, Polydor Deluxe 2302 069), one of my favorites for sticky, late-summer nights. Eno plays all the instruments in "In Dark Trees," including synth percussion that sounds like claves. Although the performance is generated entirely electronically, I'd never before heard it sound so round and woody, nor had the attacks ever been so delicately and perfectly expressed—nor had the decays ever evaporated so convincingly after each synthesized stroke. What's more, the way the notes floated in three-dimensional space, moving slightly forward and back with changes in the intensity of the strokes, caught me by surprise—after 41 years of playing this record!

But mostly what I realized, after the record had finished and I was able to put what I'd heard into perspective, was the "correctness" of the entire presentation, especially the grippiness of the bass lines, midbass resolution that uncovered some heretofore hidden details, and the convincing roundness of Eno's voice set at the center of a bubble in three-dimensional space.

At the same time, it was obvious that while the Reference 6 was definitely less dynamic, less detailed, less transparent, less fully extended or resolving in the upper octaves than the darTZeel—which costs more than twice as much—the ARC was an exceptionally skilled and unerringly convincing teller of sound stories that revealed, with every record I played, musically significant information not found in the usual checklist of sonic attributes.

Just as 10 people will describe the same event 10 different ways, some more accurately than others, different audio components will present different descriptions of the same musical event, some more accurately and more cogently than others—and a special few can polish the sound free of objectionable musical seams, even if they buff out some of the details.


Some components omit too much, and so make everything sound at first beautiful—and then, pretty soon, boring. (Some cartridges with overly burnished sound do this, for sure). Others resolve all of the detail, and produce gobs of air and crystalline highs that at first mesmerize, then grate and cause fatigue, producing a disjointed effect overall. There are records like that as well, particularly some of the older, over-equalized reissues from Mobile Fidelity Sound Lab. I've just compared MoFi's vinyl remastering of Pink Floyd's Atom Heart Mother (LP, MFSL 1-202) with the new one from the band's own label (LP, Pink Floyd/Parlophone PFRLP5), on which a sticker proclaims "REMASTERED FROM THE ORIGINAL ANALOGUE TAPES BY JAMES GUTHRIE, JOEL PLANTE AND BERNIE GRUNDMAN." While some of the other releases from Pink Floyd Records sound dull, this one is tonally ideal and coherent; the MoFi sounds disjointed and bright.

The Reference 6 managed an exceptional combination of overall perfection of timing, in which everything arrived at the right time, and lingered just long enough before gracefully evaporating. It also managed to reproduce unerringly convincing harmonic structures that produced lush, true colors and solid, three-dimensional images. If you like a meaty sound, the Reference 6 is perfect for carnivores. Its sound was decidedly lush in the mids, but without smothering the upper mids and lower trebles. Instead, the latter pushed their way forward just far enough to produce sweet, clean, believable, exciting sound.

If the recording had it, the soundstage was deep, with instruments well layered and organized in space. Some of the recent reissues on vinyl from Pure Pleasure have sounded suspiciously digital—not tonally, but spatially. This is clear when I play them through my reference darTZeel preamp, and I wanted to hear if the Reference 6 could be similarly revealing. I had that chance with Pure Pleasure's reissue of Paul Desmond's (with Strings) lush and lovely Desmond Blue, featuring guitarist Jim Hall, recorded in 1962 by Ray Hall (no relation) (LP, RCA Living Stereo/Pure Pleasure LSP-2438). On the original LP, the airy space of New York's Webster Hall is apparent behind the strings, which are clearly spread across the stage, Desmond and Hall well focused in front. On the reissue, there's no sense of space. It's a flat picture, strings and soloists mushed up against a plane. (It sounds like phase incoherence.) The Reference 6 revealed all of this, as well as the mess that is Pure Pleasure's mono reissue of Nina Simone's very first album, from 1957: Little Girl Blue (LP, Bethlehem/Pure Pleasure BCP 6028). This is a great album—so get Analogue Productions' stereo reissue (AAPJ 083), cut from the original analog tape.

Playing the Clash's very familiar London Calling, whether original LP (CLASH3) or CD, made it clear that the Reference 6 attenuated the very top to some degree. This album's usually ringing, shimmering cymbals sounded somewhat muted, and the snare, while meaty, lacked some of its crack. But this was more than compensated for by the verisimilitude of the voices—I'd never heard Joe Strummer sound so Strummery, or Mick Jones's harmonies so Jonesy—and the way the ARC put everything in order in terms of timing and space, plus its robust bottom end and overall forward thrust. The Reference 6 could definitely do rock'n'roll, despite its somewhat polite top—which ended up being very kind to grating digits.


The Reference 6 was also decidedly ready for classical. The latest reissue from the Electric Recording Company is the Brahms Violin Concerto, with violinist Leonid Kogan and Kyril Kondrashin conducting the Philharmonia Orchestra (EMI SAX 2307/Electric Recording Company ERC027). This recording was first issued in 1960; an original pressing recently sold on eBay for $889, and a few years ago a copy went for $1236 on Collector's Frenzy—the 300 copies pressed by ERC each sell for £450 (ca $585 at time of writing). The Reference 6 lost some of the air, but the harmonic structure and tonality of the violin and the overall orchestral sound were stunning enough to make me forget about gear.

Early on, Audio Research built its reputation on its tubed preamplifiers (footnote 3). From reviews I've read over the years of ARC products I couldn't afford and never got to hear, they've had their ups and downs. Friends who own the Reference 5 SE, which I've not heard, say that the Reference 6 is a major improvement in terms of both sound and ergonomics. I believe them. The Reference 6 was an absolute pleasure to have in my system. I installed it and immediately fell in love with it, so strong were its positive attributes, so ultimately unimportant its minor shortcomings.

The Reference 6 made music. I have no doubt its sound has been sculpted and contoured in a particular way, just as was the sound of the Reference 2, which I reviewed in the September 2000 issue, and which then cost $9995. Adjusted for inflation, that would be $13,979 today—just $21 less than the Reference 6. When I reread my review of the Reference 2, I saw that it hit similar sonic points. The Ref 2 is long gone from my system, but I'm confident that the Ref 6 is far superior in every way—and particularly in its top-to-bottom seamlessness and resolution of detail. And ergonomically, the Reference 6 is the product of a different and far better world.

In rereading that review, I also noticed that the Reference 2 hadn't seemed able to even suggest, let alone match, the Reference 6's ability to communicate—something you have to hear for yourself. Leaving aside the usual sonic checklist, on which the Reference 6 did a very good job of ticking boxes, its most appealing sonic qualities surely won't show up in the measurements. Bill Johnson was right.

Footnote 3: I still have the ARC SP-10 I bought in 1984 after reviewing it for Hi-Fi News & Record Review magazine.—John Atkinson
Audio Research Corporation
3900 Annapolis Lane N.
Plymouth, MN 55447-5447
(763) 577-9700

A. Hourst's picture

“That may offend the sensibilities of those purists who demand absolute accuracy, but in audio, there's really no such thing”

I don’t know what’s most funny: Michael Fremer who thinks he can “offend the sensibilities” of some objectivists, or the fact that he thinks this will happen from such an empty, predictable commonplace as the “immeasurability” of good sound.
There’s really no such thing, you say, as absolute accuracy in audio. Never mind the fact that the usual tenants of a “good enough” accuracy only ask it to be better than the human ear sensitivity, which is rather easily achieved with modern electronics, Mr Fremer don’t even recognize “absolute accuracy” as an existing horizon in audio. Absolute accuracy conceptually exists in audio as much as it exists in photography or in watchmaking. However, if someone is trying to push a 14 000$ piece of electronic whose performance can be bought for less than 1/10th the price, rising up the confusion by saying things like “in audio, there’s really no such thing as absolute accuracy” can be good practice.
One thing will never happen: a blind ABX comparison of this ARC preamp with a 1000$ similarly measuring one, to put to the test this idea that dollars can get you what measurements and science can’t.

ChrisS's picture

And has never happened, because a blind test in this situation is not practical nor very useful.

ChrisS's picture that you acknowledge that you are the only one who keeps asking for something that will never be done!

Are you the only one who needs to have your idea tested?

Johnnyjajohnny's picture

I believe a lot of people would actually like to see a blind test like A. Hourst suggests, so he's not the only one.
I, and probably many others would find it very interesting, and I'm not convinced it would necessarily turn out one way or the other. So, it would be nice to find out if there really are audible differences between two amps that measure the same :-).

Maybe you have already noticed that the blind test advocates usually ONLY ask Fremer (or anybody else) to do blind tests with certain things.
As far as I know, nobody has ever asked him to do a blind test comparing ANY of the speakers he has ever owned to a pair of 200 dollar computer speakers or even to 1000 dollar KEF speakers. Nor do I see any requests for a blind test between a Lyra cartridge and a 50 dollar Audio Technica cartridge.
And why?
Because the objectivists already know that there are readily audible differences between most speakers and also many cartridges. As for cartridges, I've compared my own cart to 35 others, and the blind tests I have done, only with the ones that were the most similar, I passed. I even passed blind tests on some adjustments (overhang, stylus pressure, etc.) that I didn't expect to pass.
Even some of the very first ABX tests done in the late 70s and early 80s showed that speakers and volume levels were by far the easiest categories to hear a difference. On that note, recently I successfully ABX'ed 0.2 dB volume difference on actual music with 15 out of 16 correct (the test I'm the most proud of).
So, the objectivists are usually (not always, as some objectivists really are obnoxious and OCD) asking for blind tests of more controversial topics.
Personally, I think that blind tests will/should reveal differences between certain amps, but some objectivists disagree, and amps seem to be the category that splits the crowd a lot. But even hardcore objectivist Arny Krueger said in "The great debate" in 2005 that he has successfully heard differences between power amps in blind tests.
Then there are categories where it's simply highly unlikely that people can hear a difference, because nobody else has done that so far in a properly conducted blind test. This category includes hi-res vs. the same material down-sampled to CD quality, analog tape vs. a properly digitized copy, and cables. However, some cables are not transparent in the sense that they can be faulty or have certain properties (impedance, etc.) that will alter the sound. Someone at Hydrogen Audio did successfully ABX speaker cables, and a measurement showed quite a different frequency response for the two pairs. Also, Audio Critic showed in the early 90s that certain cables rolled off prematurely or had a spike in the treble, and some of this is audible, and some people buy these cables for exactly those audible properties.
And lastly there's the category of products that simply cannot produce any audible difference based on the currently known laws of physics. This includes expensive power cords and tiny acoustic products by Synergistic Research. Although some people report differences, so far no properly conducted blind tests have shown any difference – quite the opposite.
It's also worth noting that Synergistic Research, Nordost and Audioquest have been shown to do fraudulent demos, where they changed the volume level and used other tricks to "show" an obvious difference that everybody could hear. Obviously, they do this as their products simply don't produce a difference.
This is why we need blind tests. Blind tests are the kryptonite for the golden eared, but also their bragging rights if they pass (I've passed many and failed many) :-).

ChrisS's picture

See John Atkinson's many, many words that he (and others) has written about blind testing and you'll understand why blind testing will not be done by Stereophile any time soon.

Bottom line, Double Blind Testing is neither practical, nor particularly meaningful when evaluating audio equipment.

Bottom line #2, no one in the entire audio industry does DBT.

On the other hand, "Single Blind" testing, even when done informally, can be fun and informative, but the results can no way be considered "scientific".

Johnnyjajohnny's picture

Everybody at Stereophile opposes double blind testing because the tests don't give them the results they want. As simple as that.
I will be blunt here and say that saying ABX tests are invalid is downright stupid.
The writings of Atkinson, Fremer et al exemplifies exactly what the problem is with the audio press: The most scientific tool (double blind testing), which is used in every other form of scientific testing of any kind, from testing medicine to people with paranormal abilities, is by the audio press deemed "useless" and "unscientific" simply because it doesn't corroborate the findings that the critics found when they could see the name tag and knew the price.
Richard Dawkins made an excellent two-part programme called "Enemies of reason" (it's on Youtube), and in the first part he speaks to an astrologer, who gives exactly the same reasons as the audiophiles, "I just don't believe in the experiment", when Dawkins suggest they give out horoscopes to random people. He also says "If your intentions are mischief, what you get back is mischief.". Fremer said: "If the test is stupid, what you get back is stupid". Same thing.
As Dawkins remarks: "I thought you would be keen to try it out if you're so sure that your horoscopes are accurate, so that makes me think that in your heart of hearts you don't belive it. I don't think you're prepared to put your reputation on the line."
When Dawkins visits a double blind test of dowsers done by someone else, they have the same excuses when they can't find water.

I've had four phono preamps in my possesion or on loan in the last couple of years. I made level matched recordings of all them, and I succesfully ABX'ed all of them. I can easily post my logs, 'cause unlike the astrologer or the staff at Stereophile I have no problem putting my reputation on the line. I haven't measured the preamps, but I think they simply have slightly different frequency responses. What the explanation is doesn't matter to me - all that matters is that I could tell them apart, usually with 15 out of 16 correct. This just goes to show that ABX tests work. If you have one minute to spend, you can verify it for yourself: Download Foobar and its separate ABX plugin. Load an Iron Maiden song as A, and an AC/DC song as B (or whatever you prefer) and then ABX them. You will have 20 out of 20 correct in less than one minute.

Bottom line, Double Blind Testing is practical, easy and very meaningful when evaluating audio equipment. All you need is a switch (all mine were done in Foobar) and some time to spend, which you would have when evaluating anyway.

Bottom line #2, no one in the entire audio industry does DBT, because then many companies would go out of business. Sure, many would remain in business and rightfully so, while others would go out of business. Some companies really do deserve to close their doors, like the scam companies like Synergistic Research and Nordost (an elaborate blind test was done with power cords from Nordost: An enormous fail) that charge ridiculous amounts of money for placebo effects and then threaten to sue when the thruth is exposed.

As for Audio Research, I know that some people love them, others despise them. I've only listened to it once, which was really just casual listening of speakers, and I have no quarrel with them.

ChrisS's picture

Please actually read the articles by John et al. And take a course on scientific research and how to set up and implement a scientific experiment.

What you express is opinion and what you describe is not science.

Allen Fant's picture

Great review- MF.
until I can demo the new Ref6, I feel the Ref5SE, is still the best tubed pre-amp in the ARC arsenal.'s picture

Absolutely well written. Yes the Reference 6 is all that and more. Even the new Foundation Series LS28 betters the Reference 5 SE now.
Yes Casework and other improvements have trickled down to the Foundation series.

Vade Forrester's picture

This was one of the best reviews I've ever read. Well done, Michael.

Vade Forrester
Reviewer, SoundStage! Network and The Absolute Sound
My words=my thoughts.

WJ ARMSTRONG's picture

I agree with my fellow reviewer Vade Forrester - this was unusually entertaining and successfully conveyed some quite subtle notions with a lovely light-touch clarity. Almost as enjoyable as listening indeed!
Thanks Michael.
Bill Armstrong - 6moons

jsch123's picture

I own it and it's lovely. The best preamp I've ever owned and it's really brought me to a point of finality . I mean, not really because I'll be tinkering for the rest of my life, but it could easily be finality. If that's even a word.

I agree with just about everything MF said. Especially the "a lot of meat on its bones". But you know it remains exceptionally open and transparent and dynamic at the same time. It's just lovely. Gone is ALL the grain. Smokes both my VAC preamps.