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Positive Feedback ISSUE 35
january/february 2008


audio space

6M-2A3PP monoblock amplifiers

as reviewed by John Zurek





Von Schwiekert VR4 jr, Optimus (Linaeum) Pro LX4 Minimonitors.

Cary SLP-88 preamplifier with Electro–Harmonix tubes, PS Audio HCA-2 amplifier, and a Aqvox Phono 2ci phono stage.

VPI Scoutmaster/JMW9 Tonearm /Shelter 501 Mk II, Cary 303/200 CD player, Sony DVP-NS755 SACD, and a Marantz CDR 630.

RS Duet Palladium, Phoenix Gold, Dunlavy Reference, Acoustic Zen MC2 PS Audio Xtreme interconnects, PS Audio Xtreme and Acoustic Zen Satori speaker cables, PS Audio Xtreme power cables.

Standesign and Boltz racks, Argent Room Lenses, VPI HW-16.5 Record Cleaner, Monster HTS 200 power conditioner, Vibrapods, Sonex panels, and AudioPrism Quiet Line filters, Auric Illuminator, Pandafeet, Herbies Grungebuster CD mat, Superior Carpet Spikes, and Iso-cups, Lionel train trestles as speaker cable elevators.

Sennheiser HD 600 headphones, Headroom Supreme headphone amplifier, iriver 450 CD player, Cowon iAudio MP3 player.


Bryan Gladstone, PFO’s national sales manager, is one discriminating audiophile. Fortunately, he has a great ear to back up his opinions. After we concluded PFO business at the ‘07 Rocky Mountain Audio Festival, Brian and I went from room to room listening for fun, shopping a little, conducting our own personal critiques. Now, I'm the first one to testify that the show conditions can be brutal—a hotel room not being the optimal venue to show off a system. But truly, some rooms were so skeevy they had us literally running away with pain. Some actually laughable, others unremarkable; like the middle of a bell curve. A few were outstanding. Bryan has the uncanny ability to listen to the system for a minute or two and determine whether it's happening or not. I’ve learned to trust him on this. He’s usually right. And although our tastes differ, we typically agree if a system is doing what it's supposed to.

Going to audio shows as a reviewer is an experience. I don't expect to be treated like royalty, but conversely I don't expect to be treated like dirt, which happens more than you might guess. Funny, some of the manufacturers/exhibitors just don't know how to talk to people, no matter who those people are. Although PFO is all about due diligence where reviews are concerned, we are also about having fun. We try not to take ourselves too damn seriously. This hobby should be enjoyable. Some of the exhibitors don't seem to pick up on that. Some act like their gear has descended down from heaven, blessings bestowed from above. A special dispensation for the pope must be signed in triplicate to get a review sample. Others ignore you totally. Some, like Gini System’s Alfie Lew, know what it’s all about. Fun.

When we arrived at the Gini Systems room Bryan said “check this room out, I think you’ll like it”. Bryan was obviously familiar with these amps. A variety of Audio Space amplifiers were making great music with a large pair of Dynaudio Contours, although I don't remember exactly which amp was performing when we were there. The presentation was huge, pleasing, and tonally correct; easily one of the better rooms in the show. After we listened to a variety of music, I spoke to Alfie about getting an Audio Space amplifier for a PFO review. “Which one do you want?” he asked.

We settled on the Audio Space 2A3 class-A push-pull monoblock vacuum tube mono block amplifier featuring point-to-point wiring and hand-wound transformers and (of course) 2A3 output tubes.

Specs are as follows:

  • Output Power: 2.5 W/ch

  • Output Impedance: 4 ohm, 8 ohm

  • Frequency Range: 20Hz-20kHz +/-1dB

  • T.H.D: <1% (20Hz-20kHz)

  • Input Sensitivity: 50-100mV LINE IN, .6-1 mV DIRECT IN

  • Input Impedance: 68Kohm

  • S/N: 89dB (Hum Noise <1mV)

  • Tube Complement: (2A3X2, 6N9P, 6N8P)/Channel

Removable tube cages are included to protect the precious thermionics. On the front panel you’ll find power and volume pots, a selector, and an NF ADJ switch. After I looked closely at the front faceplate I found a label that proclaimed “integrated/power amp” hmm—didn’t know these mono blocks double as an integrated amp. Indeed a plus.

Each mono block’s tube complement consists of a pair 2A3s labeled Audio Space for HI - END Audio, and a pair of 26N9Ps surrounded by a star with no other label. Between the tube rows are terminals for bias adjustment. At the rear end there are two large transformers labeled Audio Space AS 908 Family T114 - Z Q1.

On the back of each mono block you'll find two line-in connectors and two direct-in connectors in addition to an IEC power cord connector. Speaker outputs are 4 or 8 ohm. Also included is a black polishing cloth and a nifty pair of white cotton gloves to handle the prized glass.

The build quality is quite nice, although the only real cosmetics to speak of are concentrated on the front panel, a combination of chrome with black and gold accents. Not bothering with the stock power cords, I used a PS Audio Extreme Statement on each, both Statements fed into a PS Audio Duet that was connected via more PS Audio Extreme Statement to a Hubble 20 amp outlet in the wall.

Since the amps were already broken I hooked them up as soon as they arrived. They were very nice with the Acoustic Zen Adagios, although power was lacking. At 89dB efficiency, the Zens were just a little hard to drive with 12.5-watts, but this combination did have its moments—the Audio Space 2A3 had the uncanny ability to articulate high frequencies in a most delicate and lifelike manner that was truly startling.

Switching to the Daedalus Ulysses (more to come on this superb surprise soon) at 97dB efficiency was an entirely different story. The Ulysses proved an excellent match for the 2A3's, and was able to take full advantage of their 12.5-watts. I enjoyed a deep, wide soundstage. The low-end was a big surprise. Full, taut, and surprisingly punchy, the Audio Space did not disappoint in the nether regions. The gorgeous midrange I was expecting showed up in spades. Voices and instruments were lush, rich, a joy to listen to. The dynamics were excellent, macro in particular. The sound was very well balanced across the frequency extremes, with accurate instrumental and vocal timbres.

The Audio Space amps were able to drive the Ulysses to very loud levels in my room, and were friendly to all types of music. I listened to large-scale orchestral, string quartets, solo piano, acoustic and electric jazz, rock 'n roll, and a variety of other selections. The 2A3's did not favor any one genre. I really expected chamber music, acoustic instruments, and well-recorded vocals to shine, and did they! Once again though, the surprise was the punch these amps provided for string, electric, and even synth bass. No low end disappointment here.

The 2A3's sound is versatile, and although the midrange was great as you’d expect, I was very pleasantly surprised by the eloquent and succinct presentation of all types of music, not just the norm you’d expect from low power tubes. More so than any other amp I've heard in my room, the Audio Space highlighted the presentation on the outside and back of the speakers, not just the space in between. The result was a huge, detailed, layered soundstage that was splendid. The Audio Space amps pumped spirit through the speakers. They feel like I'm listening to music instead of a damn good facsimile, rhythm and timing suitably conveyed.

Well, Bryan was right. Again, I did enjoy the Audio Space amps, they make very pleasurable music and are easy to recommend, especially at a hair over $3k for the pair. For me this 2A3 monoblock really lit the fun lamp. Find yourself the right speaker, get a pair of these from Alfie or your dealer, sit back, and enjoy! John Zurek

Retail: $3190

Audio Space
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