January 2010

Axiom Audio A1400-2 Stereo Amplifier

Anyone familiar with Ian Colquhoun, president and chief designer of Axiom Audio, knows he likes to do things in a big way. When he set about designing his big XLF (Extended Low Frequency) DSP subwoofers, he knew the amp needed to be powerful, and decided he wanted a switch-mode design. But unlike some manufacturers, who license switch-mode technology from other companies, he came up with something entirely his own design. Colquhoun then felt that the new amp was just too good to be limited to use in his subs, and set about designing a standalone power amp based on it. His first product based on the new design, the Axiom Audio A1400-8 power amplifier, is claimed to deliver up to 1400W into any combination of its eight channels while remaining virtually unclippable.

The latest iteration of Axiom’s switch-mode amp is a two-channel version, the A1400-2 ($2620 USD). From the outside, the A1400-2 is a relatively small, unassuming-looking box -- but packed inside is a highly efficient, high-powered stereo power amplifier.

Description

The two-channel A1400-2 looks virtually identical to the eight-channel A1400-8, which I reviewed for Home Theater & Sound. Visible through the A1400-2’s top vents are a single two-channel amplifier board, and one set each of inputs and outputs on the rear panel. The same power supply as in the A1400-8 is said to be used in the A1400-2; it has an enormous toroidal transformer, and four very large capacitors with a total of 140,000µF of capacitance. Axiom rates the A1400-2’s output at 350W into 8 ohms, 700W into 4 ohms, or 1200W into 2 ohms, with one channel driven.

Axiom’s switch-mode amplifier uses extremely robust custom ICs and MOSFETs designed to handle all the power this supply can provide, and drive even difficult speaker loads without clipping. Switch-mode designs are supposed to be extremely efficient; sure enough, the A1400-2 ran extremely cool, never becoming more than barely warm to the touch.

The case is of heavy diecast aluminum, the slightly concave faceplate 1/2" thick. Overall, the A1400-2’s construction is tremendously solid and brick-like: It measures a mere 18"W x 4"H x 17.5"D, but weighs a substantial 46 pounds. Although I was very impressed by the A1400-2’s solidity and build quality, I was less than enthused about the placement of the IEC power inlet: it’s on the bottom panel. This requires that the buyer use a power cord with the correct 90-degree angle, such as the one supplied. This relatively minor issue will affect those who want to use the A1400-2 with an aftermarket AC cord.

On the rear panel, the A1400-2’s single set of inputs can accommodate balanced XLR connectors, professional-style phone plugs, or RCA connectors with the supplied adapters. There is a set of standard high-quality speaker binding posts, a power switch, and a jack for a 12V trigger input. A toggle on the bottom plate, near the power inlet, switches the input voltage between 220V and 110V.

The front panel has only a Power pushbutton; a blue ring illuminates to indicate when the A1400-2 has been turned on. The amplifier is available in black, silver, or champagne finishes.

Setup

The Axiom Audio A1400-2 replaced Bel Canto’s e.One REF1000 monoblock amplifiers in my reference system. D-to-A conversion and preamplifier duties were handled by an Anthem Statement D2 A/V processor. Digital sources were either a Trends Audio UD-10.1 USB digital audio converter fed by my laptop computer, or an Oppo BDP-83 universal Blu-ray player. Speakers were Paradigm Reference Signature S8s. Connecting everything were Analysis Plus Solo Crystal and Copper Oval-In Micro interconnects, Analysis Plus Black Oval 9 speaker cables, and Essential Sound Products AVP-16 AC cords. Surges were suppressed and power conditioned by the combination of a Zero Surge 1MOD15WI and a Blue Circle Audio Peed Al Sea Thingee.

Sound

The sleek A1400-2 may look like a mid-priced, mid-powered amplifier, but it had all the brawn and control you’d expect from its 350W rated output. It also had very little, if any, sound of its own -- also as you’d expect from a high-quality, solid-state amp. Its combination of high power output and very neutral sound was magnificent.

Rebecca Pidgeon’s The Raven: The Bob Katz 15th Anniversary Remaster (Chesky, 24-bit/88.2kHz FLAC files) sounded extraordinary. The A1400-2 made it easy to appreciate every last bit of detail squeezed from the original master tapes by the newly remastered, high-resolution version of this relatively simple acoustic album. There was an organic flow to "Grandmother," as Pidgeon switches from a conversational tone to spectacularly lyrical singing. I was able to follow the interplay of her voice and guitar, which provided a great sense of pace. The clarity of her voice was even more spectacular in the title track, with a very slight but natural sibilance and plenty of air. The A1400-2 placed Pidgeon against a background of total darkness (i.e., absolute silence) that further accentuated the purity of her voice.

The Axiom reproduced the acoustic instruments in Pidgeon’s cover of "Spanish Harlem" as exceptionally well as it did her voice. The gentle rise and fall of alternate notes on the bass were gracefully rendered, and the fidelity of the shaker was astounding. Other acoustic instruments, too, were able to convey a great sense of power, as in "It Doesn’t Matter," from Alison Krauss’s So Long So Wrong (CD, Rounder 011661036529) -- the double bass in this track was absolutely thunderous. The guitar and mandolin, too, were wonderfully and richly textured, but it was the A1400-2’s reproduction of the bass that really caught my attention: deep and extended, yet controlled in a way that connected me to the music on a visceral level. The instrument completely filled the soundstage without overloading it.

The A1400-2 was able to re-create live performances with an amazing sense of realism. Neil Young’s Live At Massey Hall 1971 (CD, Reprise 093624332725) is one of my favorite concert recordings, but I’ve recently discovered an even more involving version of his "Heart of Gold," from the album North Country, included in the Neil Young Archives, Vol.1: 1963-1972 (CD, Reprise 0093624996057). Excellent transients from the guitar deftly communicated the sense of energy in that live performance, and Young’s harmonica had just enough bite to sound genuine without annoying. Young’s rambling opening remarks were disarmingly lifelike, as was a cough from someone in the audience in the right channel. The sound of this recording was a touch warmer and richer than that of, say, "Helpless" from Live At Massey Hall 1971, which gave the former a heightened sense of intimacy. Young just sounded more there on North Country; the A1400-2 made this wonderful recording sound incredibly lifelike.

With the A1400-2’s seemingly endless reserves of power, I never wanted for more. "Salomé (Zooromancer Mix)," from U2’s The Best of 1990-2000 & B-Sides (CD, Island 04400634380), is one of my favorite tracks for assessing a system’s dynamics and power handling. The Paradigm Reference Signature S8s are relatively efficient for large speakers, but still require a fair amount of power to really get going. I could play this track at ear-splittingly loud levels and the A1400-2 still seemed to have plenty in reserve. The pounding bass was certainly impressive at these volumes, but it was the way the entire soundstage maintained its coherence that was even more astounding. Not only was there no evidence of clipping or distortion, but the imaging remained razor-sharp, and the sound was smooth and devoid of harshness. Bono’s crisp vocals were placed squarely between the speakers and slightly forward, while percussion, background vocals, and various synthesizer effects were spread widely across and farther back in the soundstage.

The A1400-2 definitely had the guts to deliver dynamically demanding recordings, but what kept me coming back to listen to my favorite discs over and over again were its finesse and neutrality. Cassandra Wilson’s voice can be difficult to reproduce. Her deep, richly textured tones are so dense that they can sometimes sound slurred or syrupy on less capable systems. No such result with the A1400-2 -- her languid voice on "Time After Time," from her recent compilation of covers, Closer to You: The Pop Side (CD, Blue Note 5099969608728), created a beautiful sonic picture. The varying intonation of each somberly sung syllable was perfectly reproduced, resulting in an intensely emotional listening experience for me. There was also a fantastic sense of the acoustic bass: each note deep and rich but not boomy, the woody slap of the instrument well demarcated from its sustained resonance.

Comparison

My usual amplification in this system is a pair of Bel Canto e.One REF1000 monoblocks ($3990/pair when available). Although the Axiom A1400-2 costs significantly less, when I substituted it for the Bel Cantos there was no dropoff in the system’s performance or in my enjoyment of it. In fact, I heard a slight increase in transparency and neutrality with the Axiom. Cassandra Wilson’s voice in "Time After Time" was a little less expressive through the Bel Cantos, which glossed over some of her subtlest inflections. However, her voice had a luxury and a richness through the e.Ones that was intimate and appealing. The bass still had a wonderful sense of "woodiness," but also seemed just a touch looser.

The bass of U2’s "Salomé (Zooromancer Mix)" was a little less taut with the Bel Cantos, but not significantly so. It was only through repeated and tedious comparisons that I was able to conclude that the Axiom A1400-2 was, in fact, more capable in the lowest frequencies. The Bel Cantos threw up a huge soundstage, but the image outlines within that soundstage were a little less precise. The placement of the percussion, for example, was not as razor-sharp as I experienced with the Axiom. Both amps could play incredibly loud. The Axiom is rated at only 350Wpc into 8 ohms vs. the Bel Canto’s 500Wpc, but both could play as loud as I could stand with no perceptible distortion.

The Bel Cantos evinced a touch more warmth than the Axiom. Although this wasn’t enough to color the sound, it did add a touch of smoothness to closely miked vocals. The dynamics of Livingston Taylor’s voice on the 24-bit/96kHz recording of Ink (DVD-V, Chesky 090368017925) are astounding on tracks such as "Isn’t She Lovely." It wasn’t that the Axiom sounded harsh, but that the Bel Cantos sounded a tad smoother and less forced. The whistling at the beginning and end of the track wasn’t quite as piercing through the Bel Cantos, but still sounded very realistic.

While there were some minor differences between the sound of the Axiom Audio A1400-2 and the Bel Canto e.One REF1000s, these amps actually sounded very similar -- so similar that I’d happily use either as my reference amplification. The fact that the stereo Axiom costs nearly $1400 less than the pair of Bel Cantos makes it, comparatively, an excellent value.

Conclusion

Other than the somewhat inconvenient placement of the power inlet on the bottom plate, I found nothing to fault in the Axiom Audio A1400-2. Its combination of excellent, neutral sound and high power output were unexpected in a stereo amplifier costing a relatively inexpensive $2620. Due to its unexpectedly high level of performance, I wouldn’t hesitate to pair it with large, relatively expensive speakers such as the Paradigm Reference Signature S8 ($6000/pair when available) -- as I did in my reference system.

Because Axiom Audio is primarily known for making loudspeakers of high value and offering them at reasonable prices, many audiophiles might never consider purchasing an amplifier from them, especially one for a high-end, two-channel, audio-only system. That would be a mistake. There’s a reason we made Axiom’s eight-channel A1400-8 amp a Reviewers’ Choice.

The A1400-2 is equally deserving of this accolade. If you’re searching for a powerful, great-sounding stereo amplifier at a price much lower than you might expect to pay for its level of performance, don’t overlook it.

. . . Roger Kanno
roger@soundstage.com