In direct comparisons with Parasound's Halo A 31 three-channel amp, the AT543nc seemed to offer more lower midrange, less treble, marginally more richness, and a slight tilt in balance. The ATI seemed to present a bit less air and space, but I can't say whether the Parasound is any more accurate in this regard. However, all that was noted only briefly upon switching from one amp to the other. The ATI and Parasound both had smoother, more enjoyable sound with Focal's Sopra No3 speakers than did the Classé Sigma Monos, which unsympathetically revealed some upper-midrange glare in some recordings.

I also tried the AT543nc's unbalanced inputs, using Cardas Cross 10m cables. The overall level was down about 6dB, as expected, but the sound quality was unchanged.

Conclusion: I am completely taken with ATI's AT543nc. It seemed to do everything right, and didn't get in the way while communicating the elements and the spirit of the music. I wish I'd had on hand its older cousin, the Theta Dreadnaught D, for direct comparisons, but given the Theta's higher price ($7099.95) and weight (90 lbs), any outcome could not possibly blemish the $3295, 57.5-lb ATI AT543nc.

Monoprice Monolith 3 three-channel power amplifier

Monoprice.com is a popular websitea place where those in the market for cables, connectors, switching devices, or associated tools know they can find what they're looking for, and at reasonable prices (footnote 2). Monoprice's inventory is encyclopedic, and they offer great how-to aids for noviceswhen I rewired my cable TV system, I relied on them for the cable, connectors, tools, and guidance. Given their success, it's not surprising that they've branched out into more sophisticated offerings, such as their well-priced, high-speed, active HDMI cables and A/V products. Their Monolith line of power amps is, for them, a big step into a new market.

The Monoliths are 200Wpc class-A/B amplifiers offered in versions for two, three, five, and seven channels. All models come in identical cases measuring 17" wide by 7" high by 13.3" deep; the only distinguishing features are the model number on the front panel, the number of connectors on the rear panel, and the weights, which range from 48 to 94 lbs. The prices range from $999.99 (two channels) to $1499 (seven channels). Like Goldilocks, I chose an in-between model, the three-channel Monolith 3, at 57 lbs and $1099.90.

Description: The Monolith 3's appearance impresses as cleanly designed and executed. The main housing is rigid, with a central, illuminated On/Standby switch on the faceted faceplate. On the right of the sturdy rear panel, from bottom to top, are an IEC power inlet, the main power switch, a ground terminal, and a 12V trigger input. The rest of the rear panel is occupied by an unbalanced input jack (RCA) and a pair of multiway speaker posts for each of the three channels. The speaker terminals are finger-friendly, but I plugged my cables' bananas right in. The gold-plated RCA jacks are firmly mounted on the rear panel, not on internal PC boards, from which they might be loosened by normal use. My only cavil is that the sheet metal of the case seemed a bit thin compared to the rest of the hardware. It didn't rattle or buzz in use, but it might benefit from the internal application of some damping material.

The Monolith 3's specifications are impressive. Its FTC full-bandwidth power output is 200Wpc into 8 ohms or 300Wpc into 4 ohms. Total harmonic distortion and intermodulation distortion are each less than 0.03%, and the A-weighted signal/noise ratio is greater than 120dB, all referred to full output power. (In addition to listing the specs on their website, Monoprice supports them with an eight-page document of test results.) The Monolith 3 weighs 57 lbs, most of that weight due to its single 1025VA toroidal power transformer. Unfortunately, the toroid is at the front left corner of the case; the uneven distribution of weight makes it a bit harder to heft the Monolith 3 than other amps of the same weight.

Since the Monolith 3 lacks balanced (XLR) inputs, I dragged from the back of my closet some 10m-long Cardas Cross cables terminated with RCA plugs and used them to link the Monoprice to my Parasound Halo P 7 7.1-channel preamplifier.

Stop a moment and reflect on all I've just described. The Monolith 3 is a well-constructed power amp with excellent specs and all the power that any normal listener with a trio of normal speakers to power can use. If it sounds good (it did) and doesn't blow up (it didn't), it's a bargain at only $1099.90. And at this point, many of you might just stop reading and buy one.

For the rest of you, I press on . . .

Listening: The music flowed. Despite the length of the unbalanced connection, I heard no problems with noise. The sound was right and full, with an emphasis on the lower end of the audioband. Remember, unless I'm reviewing a loudspeaker, I use the default target curve of Dirac's Live room-correction software for all of my auditioning and listening. So when I say that I hear a change in balance with any new component other than a speaker, that's based on what I hear relative to the component that the review sample has replaced, and not on any absolute reference. That said, the Monolith 3 sounded a bit warmer than any of the other amps I have on hand, and while this will be a positive for many, I am not among them.

Despite that, the Monolith 3's reproduction of tonalities was more than acceptable, and its soundstages, in stereo or in multichannel, were ample, wide, and deep, with voices and instruments stably positioned on them. The Monoprice's bass extension and power were formidable, and its midrange and treble seemed smoothly extended. I played all my standard test tracks, ranging from solo voices and instruments to raging massive forces. Through the Monolith 3 they sounded clean, unstrained, and richalmost beyond criticism. Overall, the Monolith 3 was conducive to relaxed, extended enjoyment of musicuntil I put on my critic's cap and looked for trouble.

The troubles I had with the Monolith 3 were its lacks of air and space, and of the crisp delineation of individual voices and instruments. Given the amp's power capability, this did not correlate with volume levelthe Monoprice sounded much the same at all levels. Rather, it seemed to correlate with instrumental complexity, and became more noticeable as the size of the ensemble increased. Some of this, undoubtedly, had to do with the amp's spectral balanceto be sure, the Monolith did not suffer from any excess brightness that might have emphasized space and detail. Well-recorded solo guitar and violin seemed a bit warmer than I am used to hearing from my system.

When I played that spectacular recording of Matheson's String Quartet, each of the four instruments sounded clear, but there was less differentiation of them when they all played together, as in the opening chord. And take almost any of the Channel Classics recordings by Iván Fischer and the Budapest Festival Orchestraeg, Tchaikovsky's Symphony 6 (SACD/CD, CCS SA 37016)which are notable for their realistic documentation of the sound of an orchestra in a sympathetic acoustic: Through the Monolith 3, the orchestral chords sound compacted and homogenous, and less like an ensemble of players.

Conclusions: Perhaps I'm being unreasonable in judging this powerful, inexpensive, more-than-capable three-channel power amplifier by absolute standards. The Monoprice Monolith 3 was really easy to listen to, and, at the risk of insulting home-theater enthusiasts, it did a great job with the Blu-ray of Star Trek: Beyond. It might be more suitable with brighter speakers, or in rooms with insufficiently sound-absorbing furnishings. But the Monolith 3 is hard to recommend to critical music listeners who've been scrupulous about their systems.

Coming Around in the Round

As I write, the 2017 Consumer Electronics Show is just around the corner, and it seems that lots of interesting things are on their way: new multichannel server/players from Baetis and Fidelizer, exaSound's new e38 DAC, and three-DAC stacks for multichannel from Playback Designs and Mytek. And a surprise.

Footnote 2: Monoprice, 11701 Sixth Street, Rancho Cucamonga, CA 91730. Tel: (877) 271-2592. Fax: (909) 989-0078 Web: www.monoprice.com