Stereophile Guide to Home Theater

Amplifier Technologies, Inc. AT1505 Amplifier

Multichannel Power Amplifier
by Fred Manteghian

My boss’s church holds a yard sale every October in picturesque we-like-‘em-Rich-field, Connecticut, where they take in enough money to send an underprivileged family of eight on a two-week, all-expenses-paid trip to Europe while the roof is being re-slated. Aware of my affection for vinyl LPs, the boss usually invites me over for a private showing so I can cherry-pick that year’s offerings. It’s despicable, I know, but rest assured that I’ve never struck pay dirt. In fact, judging from the quality and condition of the other items I’ve seen awaiting sale, I’d say any true bargains were few and far between. But if I’d spotted one Amplifier Technologies AT1505 5-channel amplifier among the bric-a-brac, I’d have instantly reversed my position.

The $1,695 AT1505 is a large, solid, serious amp that is entirely over-engineered for its low price and respectable (but hardly remarkable) 150 Watt per channel rating. As if to punctuate its no-nonsense attitude, the owner’s manual includes the following admonition in bold, capital letters, more ominously prophetic than storm clouds before a sea battle: "WARNING: DO NOT, UNDER ANY CIRCUMSTANCES, LIFT THE GROUND FROM THE PLUG USED WITH THE AT1505 - SEVERE SHOCK MAY RESULT."

Never have I taken that ubiquitous warning so seriously as with this amplifier. From the front panel’s expanse of black metal and the red laser-guided pilot light embedded in the power switch, to the imposingly utilitarian rear deck that would be as easily at home on a Craftsman battery charger, the AT1505 is not an amplifier to be taken lightly. And at 73 pounds, it certainly won’t. I might add my own warning: DO NOT, UNDER ANY CIRCUMSTANCES, DROP THE DAMN THING ON YOUR FOOT!

Each channel is protected by two 8A fuses and dual pilot lights that let you know when a channel has gone south. Of course, since the business end of the amp usually faces a wall, hearing acuity is still your first line of defense. Inputs include a DB25 connector and individual, gold-plated, single-ended RCA jacks. Each pair of speaker terminals is encased in a clear plastic flange with slits that give bare wire and smaller spades access to the conductive posts within; dual or single bananas can be inserted into the exposed plastic endcaps.

Unfortunately, the amp can be remotely powered up only from the surround processor via the DB25 connector. Call me old-fashioned, but - knowing my flavor-of-the-month preference for individual interconnects - even if my processor had a matching DB25 output, I doubt I’d use it. In custom installations where reaching for the amp’s power switch might ruin the mood, you could always rig up something using both the DB25 and individual interconnects, as long as your processor offers some kind of 12 VDC control signal for the former.

Finally, there are no rack-mount handles on this amp, and for good reason. After telling you an optional rack-mount panel is available, the manual immediately states that the rack-mount panel cannot support the weight of the amp. I love a sense of humor.

Soundstage champ
I don’t know what I was expecting from a multichannel amp with a plain face, an ugly butt, and a standing invitation to Jenny Craig, but it wasn’t a soundstaging amp. But no matter what I threw at it, the AT1505 slew me with its soundstage. Old favorites like Supertramp and Traffic came to life in ways I’d characterize coyly as altered states. Instruments way off in the wings were way off in the wings. The decay of artificial reverb didn’t sound all that artificial anymore.

In Supertramp’s "Dreamer" (Crime of the Century, A&M CD-3647), voices waft in and out throughout a quiet interlude until the reverb dials are finally cranked down, and pow -they’re in your face with no mistakes. The long, slow fade-in on the title track of Traffic’s Low Spark of High Heeled Boys (Island 7 90026-2) started so far behind the speakers that I’m sure border guards in Texas must have chalked it up as a false alarm.

The sense of depth and holistic presence the AT1505 imparts to music is in no small part due to its nearly incomparable degree of resolution. Depending on the source, the resolution varied from very good for standard fare to breathtakingly inspired on the finest material.

Heading up the latter camp is Unmarked Roads, Doug MacLeod’s latest outing (AudioQuest Music AQ-CD1046), specifically "Lost Like the Wind at Night." From MacLeod’s opening finger taps on his acoustic guitar to his painfully emotional lyrics about other Vietnam vets who, unlike himself, saw what we euphemistically call "action", the amp leaves nothing out. The AT1505 dishes up resolution with the same fervor as the Martin-Logan Request electrostatic speakers that have captured my head and heart.

Tone it down, will ya?
Sorry, no can do! The top end of this amp is not recessed in the slightest. But don’t run to the medicine cabinet to dig out the cotton balls (they’re next to that stained bottle of wart remover) just yet. The midrange magic whose glories often lull audiophiles into accepting compromises at the frequency extremes is not a factor with the AT1505. The midrange is magical enough - not with the "palpable presence" of an overly ripe lower midrange, but in spite of it. If anything, the lowest portions of the midrange are somewhat reticent; certain vocalists, such as Marc Cohn, come off with the slightest bit of their foundation eroded.

However, it is the top octaves that stand out as some of the most airy and spacious I’ve heard. With material that is inarguably top-heavy, a degree of grain is evident, but it does not impinge nearly enough to make me accept a reduced top-end extension. Whatever treble hardness exists in a recording isn’t glossed over - bright is still bright - but the AT1505 merely gets it out of the way and lets you move on.

Running through the bass, the AT1505 is certainly competent, though perhaps less forceful than my memory of the bass-loving Marantz MA-700 monoblocks reviewed in the January 1998 issue. The Marantz tends to sustain bass notes with a bit more passion. On the other hand, the AT1505 has a more finely creased leading edge and much better resolution, particularly with heavily layered material.

Though the tonal palette on Masters of Reality’s "100 Years" (from Sunrise on the Sufferbus, Chrysalis 101197) gets quite thick and bottom-heavy, Googe’s bass playing is fluid and easily discernible in the morass. Considering that a 5-channel amp is intended for a home-theater setup with its de rigueur self-powered subwoofer, the strength of the lowest octaves isn’t the liability one might imagine.

Tonally, the AT1505 will never be mistaken for a mellow tube amp. I wouldn’t call it "bright", and for the most part its open treble is a relief from the many closed-in, life-less solid-state amps that seem to be proliferating these days (perhaps, ironically, to counter complaints about "transistor" sound). Amplifier bucks the trend and, with one exception, succeeds. The AT1505 exhibits a mild degree of sibilance that is detectable with music on both the Alón Point V speakers in my music room and the Martin-Logan Request speakers in my home theater, but I can’t say I ever noticed it with dialog. Unlike typically "hot" amps, this sibilance doesn’t impose itself across the board by turning crash cymbals into stir-fry sizzlers. Sibilants depart as quickly as they appear, but if it’s in the recording, the AT1505 doesn’t hide it.

No matter what I threw at it, the AT1505 slew me
with its soundstage.

Matching rhythm and pace with some better amps around is not an easy task, and perhaps this is where a sub-$2,000 arc welder might meet its match, but once again I was pleasantly surprised. The aforementioned title track from Traffic’s Low Spark of High Heeled Boys can sound ponderously slow on the wrong equipment, but the combination of the AT1505 and the Alón Point Vs proved up to the task.

The transient precision that worked to such good effect in the bass perseveres further up the frequency chain as well. If I said cymbal crashes were crisp, guitar strings ring, and piano attacks leave you licking your wounds, you might assume the amp is aggressive to a fault. In fact, I would guess it is the very precise attention paid to tracking the notes that gives this amp its startlingly addictive resolution and magnified, coherent insight into the recording venue.

Slouching toward obsession
Eventually I was able to abandon the hedonistic pleasures in the music room and lure the beast into the home-theater room, where, alas, it belongs. Upon entering the room, I’d swear the amp leered at the quintet of massive Martin-Logan speakers. Comfortable that I’d nailed the sonic signature of the AT1505 on the head in my two-channel room, all that was left was to sit back and enjoy.

And enjoy I did. Direct via satellite, I sat mesmerized by the soundtrack from The Accidental Tourist, a film I’ve slept through on several occasions. Without zeroing in on anything specific, I found myself simply involved in the film to a nearly unnatural degree. Well, unnatural for me - two hours of dialog among three characters (even when one of them is Gena Davis) shouldn’t be enough to hold my attention, but something was definitely at work here. With a Theta Casablanca and five of Martin-Logan’s finest, I’m not saying that the amp alone was responsible, but neither was it the weak link.

Whether it was playing Dolby Pro Logic, Dolby Digital, or DTS soundtracks, the surgical resolution demonstrated by the AT1505 in the music room was augmented by three more channels in the home theater with wildly positive results. Switching to a more recent Gena Davis project, The Long Kiss Goodnight in DTS (Image ID3738LI), I was impressed with the system’s ability to pursue divergent threads in the soundtrack while bringing deeply buried content up for air. For example, this was the first time I noticed the dog-and-cat choir on the TV singing "Three Blind Mice" while Davis’ alter ego slices and dices in preparation for the film’s concluding cookoff.

Even more significantly, dialog was perhaps the clearest I’ve heard in my room. Every movie has a few lines of dialog that are spoken too quickly, too softly, or just plain mumbled; short of playing them back a few times, they fall by the wayside, never to be heard from again. Such was not the case this time. The AT1505 came through without the slightest edge, its wonderfully extended upper frequencies infusing the human voice with the full palette of harmonics needed to cross the line from "almost there" to "just right".

I said this amp is a soundstaging champ and I meant it. Both depth and width, which are artificially woven into most soundtracks, are present in exactly the right measures to turn your simple living room into a cavernous chamber more akin to the screening room where the movie was first shown. To me, that’s the real trick for any home theater - transporting you from the miserably pathetic existence into someone else’s miserably pathetic existence. Beam me over!

Do not, under any circumstances, drop the damn
thing on your foot!

In the lower frequencies, the AT1505 isn’t the most dynamic amp I’ve heard in this room. The Parasound HCA-2003 three-channel amp had more sheer slam in the Bambi-bashing scene in The Long Kiss Goodnight, literally making one friend jump off the couch. Although the Atlantic Technology subwoofers pick up the brunt of the work in this scene, the upper bass is still the domain of the AT1505, and while it isn’t wimpy, it misses by a small margin. Were my friend there, he might have only shifted slightly in his seat.

Elsewhere, the amp has all the punch anyone might want. The attack of Don Henley’s snare on the Eagles’ Hell Freezes Over laserdisc (Geffen/Image ID3061GF) is cutting. From the midrange up, the AT1505 demonstrates the kind of dynamics most amps reserve for the bass, smashing cymbals with body and real weight. On the negative side, this amount of upper-frequency energy might easily turn acerbic on hot recordings. Though I never consciously characterized the amp as "bright" with movies, the symphony of steel-string guitars occasionally sounded a bit crisp. More problematic, vocalists such as Sting are egged on, becoming brittle by small degrees. Again, if the price for exorcism is a reduction in overall resolution and clarity, it isn’t a tradeoff I’d accept.

Blind date
While the look and solidity of the AT1505 inspire confidence, there’s nothing elaborately aesthetic about its design. To gingerly apply personification, let’s just say this amp has a great personality. Some of its more admirable traits:

First of all, the soundstaging is beguiling on the best material, and more than adequate for anything I’ve run into with video. Add to that a degree of resolution and transparency that is refreshingly addictive and so unlike what you’d expect from an amp in this price range, and even your jaded audiophile friends will take notice. Finally, its open and airy upper frequencies do justice to the occasionally beautiful but often ignored background music on soundtracks from Fargo to First Knight and all letters between.

It’s obvious that I like this amp, and I wouldn’t hesitate recommending it. However, it won’t do anything to cure a system that needs fixing. On the cleanest of systems’ the AT1505 should be a revelation. But if your system sounds etched or bright, or sorely lacking in lower-midrange warmth, you might be happier with the Marantz MA-700 monoblocks. You give up a lot of resolution and airiness that are highlights of the AT1505 by switching to the Marantz, but that little monblock has a few nice surprises going for it as well. The mild degree of sibilance noted from the AT1505 could be more pronounced and objectionable with your system, so, as usual, a home trial is definitely in order.

While I might think of a 5-channel amp priced under $2,000 as a real bargain, I’d have trouble saying that with a straight face to someone at a church picnic whose struggling to spend a quarter of that for a surround receiver. High-end bargain or not, you shouldn’t cut a lot of slack for this kind of jack. Competent performance at this price point should be given, so an amp has to offer more than that to earn a high recommendation. The Amplifier Technologies AT1505 does.