Audio Research REF 110 Power Amplifier

Published On: October 26, 2008
Last Updated on: October 31, 2020
We May Earn From Purchases Via Links

Audio Research REF 110 Power Amplifier

Audio Research, by name, suggests reference-level audio performance but even the Minnesota-based company "guilds the lily" as Mario Batali says with their top of the line products. With the sweetest tube sound money can buy - ARC offers a musicality that many say just can't be had from solid state electronics. Learn more about the ARC REF 110 amps here.

Audio Research REF 110 Power Amplifier

  • The staff at is comprised of experts who are dedicated to helping you make better informed buying decisions.


If any series of products has served up with impeccable consistency the sort of behavior that leaves you awestruck, it's the Reference family from Audio Research. It possesses the kind of track record you associate with Porsche, Leica and precious few other dynasties: five-star performance again and again and again.

Additional Resources
• Read more amplifier reviews from
• Find a receiver to pair with the REF 110 from Audio Research.

Having completed the lineup last year with a CD player and phono stage, ARC decided to add a tang of populism by issuing a single-chassis, stereo power amplifier worthy of inclusion in this particular clan. So now the range is accessible to a few more with merely deep pockets, as opposed to those who own football clubs and Maybachs.

Admittedly, £8490 is still a heady price tag, but you must put it into context: it's less than half the price of the REF 210 monoblocks. Given the way the 110 drove the hungry Sonus faber Guarneris, you'd be hard-pressed to justify the extra power of the bigger REF offerings in rooms under five by eight meters. Well, unless your name is Lemmy, or you run stupidly inefficient speakers.

ARC's corporate missive is quite clear as to why the REF110 exists: "It is perfect for anyone who does not require the high power provided by our larger monoblock Reference amplifiers." It's that simple. While the REF110 is never going to be described as "compact," a stereo unit with measurements of "only" 19 by 8.75 by 19.5 inches (WxHxD) will cause far less consternation than a brace of similarly-dimensioned chasses. It is precisely the same size as a single REF210.

Blessedly, you're spared the grotesque vacuum-fluorescent display of the REF210. Lord knows that the information it provides is truly useful, and - keeping my prejudice in check - if I were ARC's product manager, I would be pushing for a REF110D with the info panel, for an extra grand, for those who crave a display. But who on Earth chose that noxious green horror? With all the cool LCD panels out there, ARC could have specified something far less bilious. But I digress: the REF110 is as pure an amp as you will ever find.

Look at it: an unadorned box, yet unmistakably a product of Audio Research. The thick front panel bears only an on/off rocker switch and a tiny green LED. The back? Nothing more than robust custom-made speaker terminals for 4/8/16-ohm operation, XLR-type balanced signal inputs, a mains fuse and a socket for a 20-amp detachable IEC AC cable adorn the back. Additionally, since this is the era of the custom installation, the REF110 also has two 12-volt triggers (input and output) to allow remote turn-on. That's it - all you need. Perfect. Just what an amplifier should be.

It's inside where you find the fascinating grubby bits that justify the "Ref" tag. Its internal layout resembles that of the REF210, with right and left channel boards mounted horizontally, on either side of the trio of transformers that ARC has mounted on a raised central channel bisecting the unit: the mains transformer is just behind the front panel, with the output transformers lined up behind it.

Those boards are filled with such niceties as a small LCD display indicating tube life in hours, mounted on the front of the right channel board and visible through the top. There are two small 12-volt DC fans on the rear panel, the heat exiting through apertures at the back. Listeners ultra-sensitive to their whisper-quiet operation will love this bit: a small internal switch allows users to set their speed to low, medium or high.

Like the model number suggests, this amplifier delivers 110 watts per channel, courtesy of a push-pull, fully-balanced circuit containing two matched pairs of 6550C output tubes per channel. The hybrid input stage employs direct-coupled JFETs with a 6H30 gain stage and 6H30 cathode follower. Biasing is not automatic, so here's a use for your digital volt meter. The procedure is explained in detail in the manual, and it is accomplished using insulated test points on the main boards. The output section is a combination of classic ultra-linear topology and Audio Research's "partially cathode-coupled" topology, which the company argues as capable of "yielding better sound than conventional pentode or triode operation."

As mentioned before, this unit adheres to Reference practice in providing only balanced inputs - 300K ohm impedance and via XLRs. It's non-inverting, too, but I trust that all seasoned audiophiles set polarity by ear. Better still, they use preamps with an inversion switch.

After manhandling this 67.4 pound beast into position, I connected it between the McIntosh C2200 preamplifier and my trusty Sonus faber Guarneris. I soon found out that the speakers prefer the eight-ohm taps, the bass tightening up considerably and the dynamic swings seeming more fluid and greater in spread from low levels to high. The dynamic range was, it turned out, one of the REF110's most seductive qualities, along with the most liquid and natural bass I've heard since the days of the original Class-A Krells.

Read more about the REF 110 on Page 2.

Audio_Research_REF_110_amp_review_inside.gifSo let's get one thing out of the way: if you're one of those who
buys into that bullshit about the system rather than the recording
possessing pace, rhythm, ad nauseam, this will have you snapping your
fingers and pretending that you're a 1950s beatnik prone to uttering
phrases like "Cool, man, cool." For the rest of us, the experience is
far less metaphysical. The REF110 simply handles the lower octaves with
such ease that you'd swear someone sneaked in a theoretically perfect

But that's just one small, though fundamental, part
of the package. What's so deliciously enticing about the REF110, what
makes me want to cash in my son's university fund or next year's tax
payment, is a natural, sibilance-free, warm and cuddly mid-band that's
going to antagonize anyone ever suckered by the 300B single-ended
triode merchants. This has all the alleged humanity of that overrated
valve, but with none of the near-psychedelic colorations, nor the fat
bottom that would cause mass resignations of the board of directors at
Weight Watchers.

Take Julie London, for example. (Magari ...)
One of her final LPs was a weird assembly of lustful covers of
then-current hits, including the title track, "Yummy Yummy Yummy" -
yes, the inane bubblegum epic. Through her pipes, it turns into a
salacious come-on that will have Viagra supplies gathering dust. And
that's even through an MP3 player. Feed it into a system with the
REF110 at its core, and the recording blooms into a smoky, hazy,
come-hither siren song that would find Mary Whitehouse spinning in her

Shift gears to the new Rory Block album, The Lady and
Mrs. Johnson (Ryko RCD10872), and you get sultry blues vocals on top of
the tangiest, twangiest bottleneck Ms. Block has ever delivered. A
sparse recording, it allows you to hear into the performance, thus
uncovering another of the REF110's talents: damn, can this beauty
recreate space. Transients float and vanish before you, decaying notes
drift into the ether ... steady on, Kessler. You're at risk of waxing

But that's what the REF100 does to you. Ordinarily, I'd
rather floss with barbed wire than listen to children singing, but even
the wee tykes on Brats on the Beat: Ramones for Kids (Go-Kart GK129)
were tolerable. Maybe toddlers singing the best of the Ramones' canon
is too much for some of you to take, but trust me, it works. I suppose
the other way you might wish to experience the blending of similar
voices, assessing their meshing, as well as the retention of their
individual properties, would be to subject yourself to Pink Floyd's
"Another Brick In The Wall."

As with all great components, the
REF110 inspires epic listening sessions. What these demonstrate is
whether or not the unit causes listener fatigue. Epic sessions and
listener fatigue are mutually exclusive. If I were allowed to rid this
magazine of its ludicrous points system, I would devise the ultimate
"audio litmus test": How long can you listen to a product without
feeling the need to switch it off? If the only distractions are your
stomach, your bladder, or the need to sleep, then you're onto a winner.
The REF110 isn't a mere winner. It's a champion. It's flippin'
Schumacher, season after season.

It was the sort of session that
was becoming less and less frequent, jaded old whore that I am. It
takes a lot to float my boat these days. But I couldn't tear myself
away from the REF110. For an amplifier to do equal justice to music as
disparate as the Ramones and Dean Martin, to complement both analogue
and digital sources, to sound terrific even before a sensible warm-up
period ... even I couldn't resist "just one more album, one more track."

because it ticks all the boxes. I genuinely couldn't find anything to
criticize, but I can imagine a certain type of listener finding it a
shade too silky, too intimate. Even though it offers the speed and
detail and precision of the finest solid-state designs, those wedded to
transistors might miss that final frisson of ultra-hygiene. I can liken
it only to pornographic preferences: au naturel, or a Brazilian. Call
me a hippie.

Even though my respect for Bill Johnson and the
Audio Research team is right up there with my regard for Nagra, Krell,
Wilson and other consistently front-rank brands, I wasn't expecting
this level of magnificence. The larger Reference power amps impressed
me, but they didn't make me want to rob a bank. Not so the baby of the
brood. The REF110 revives that school of thought which postulated that
the finest-sounding amps of all time have been medium power models,
say, 60 watts to 125 watts. Maybe that's what I'm sensing: finesse over
sheer force. In this respect, the REF110 reminds me of my all-time
faves. I love its sound as much as that of the mono 15-watt Radfords,
Dynaco's Stereo 70, the valve Nagras and the McIntosh MC275.

Yes, my friends: it's in that league.

Gordon Brown's dumb-ass, right-on fiscal attitudes soon to put the
final nail in this country's coffin, I'm not spending any money beyond
basics for the foreseeable future. But if I suddenly strike it rich,
I'm buying this amplifier right after I find a mint 1950s Blancpain
Fifty Fathoms watch. Here we have a product that unreservedly deserves
the appellation "Reference." The only thing more musical is reality.

About Audio Research's Reference Series
over a decade, Audio Research has dubbed its flagship range the
"Reference Series," arguably a show of chutzpah guaranteed to elicit
howls of incredulity amongst the whining hacks of the audio press. But
the Minnesota-based company is too experienced with the ways of the
audio world, and the then-semi-retired Bill Johnson and his team were
not going to allow any scope for accusations of hyperbole. In a way, it
was almost a retro move recalling early days of Audio Research, when
cost-no-object or zero-compromise amplifiers appeared with less
fanfare. Think D-150 or SP-10.

With the original REF1 preamp and
the REF300 mono power amplifier, ARC raised a bar that they have
continued to elevate with every evolutionary step. 300 watts became
600, then the vertical 610T turned up with an all-singing/all-dancing
display. A smaller 210 monoblock followed, leading to the model under
review, the first stereo product in the range. The preamp is now up to
REF3 status, while the REF CD7 CD player and REF PH7 phono stage
provide source components worthy of any of the preamp/power amp

Which begs only one more model for ARC to realize: wouldn't you just love to see an REF Integrated?

Additional Resources
• Read more amplifier reviews from
• Find a receiver to pair with the REF 110 from Audio Research.

Subscribe To Home Theater Review

Get the latest weekly home theater news, sweepstakes and special offers delivered right to your inbox
Email Subscribe
HomeTheaterReview Rating
Overall Rating: 
© JRW Publishing Company, 2023
As an Amazon Associate we may earn from qualifying purchases.

linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram
Share to...