Let’s just cut to the chase and sum up the Emotiva Stealth PA-1 Balanced Class-D Monoblock Power Amplifier in one word. That word is “FIRST.”
  • The Emotiva PA-1 is the FIRST Class-D amplifier I’ve heard that I could even remotely call “audiophile quality.”
  • The PA-1 amp is the FIRST Class-D amplifier ever offered by Emotiva.
  • The PA-1 amp is the FIRST Emotiva product that has NO active Emotiva circuitry in it at all.
  • And the amp is the FIRST Emotiva monoblock amplifier to be offered at such an enticing price.

The Emotiva Stealth PA-1 Balanced Class-D Monoblock Power Amplifier is an exceptionally great amp, regardless of price, regardless of weight, and regardless of circuit configuration. Emotiva shoots themselves in the foot by even mentioning “studio” use in conjunction with this amplifier, although it is undeniably suitable for use in a studio. If anyone doubts that Class-D amplifiers are ready for audiophile prime-time, one listen to this amp should put them on the straight and narrow. This amplifier has it where it counts!

Emotiva PA-1 Balanced Class-D Power Amplifier

Highlights

Emotiva PA-1 Balanced Class-D Monoblock Power Amplifier

  • The midrange transparency and dimensionality of the Emotiva Stealth PA-1 Balanced Class-D Monoblock Power Amplifier puts high-end audio into the price range of the “average” audiophile
  • The treble of the Emotiva PA-1 is clear, clean, and extended
  • The bass of the Emotiva PA-1 amplifier, although not the very best of the best, greatly improves once the amp is fully warmed up
  • The diminutive size and weight of the Emotiva PA-1 make it easy to integrate into most any setup
  • The cool operating temperature makes the amp easy to run
  • The amp’s high efficiency in converting electrical power to music make it inexpensive to operate
Introduction

I’ve owned Class-D amps before, but they weren’t like the Emotiva Stealth PA-1 Balanced Class-D Monoblock Power Amplifiers.

EMOTIVA POWER AMPLIFIER REVIEW SPECIFICATIONS
CONFIGURATION:

Bang & Olufsen ICEpower ASC300 module

CHANNELS:

One

OUTPUT POWER:

140 watts / 8Ω / @ 1kHz / @ 1% THD
135 watts / 8Ω / @ 0.1% THD
300 watts / 4Ω / @ 1kHz / @ 1% THD
270 watts / 4Ω / @ 0.1% THD
450 watts / 2.7Ω / @ 1kHz / @ 1% THD

INPUT IMPEDANCE:

47kΩ (balanced)

VOLTAGE GAIN:

28dB

BANDWIDTH:

20-20kHz (full power)

THD+NOISE:

0.005% @ 1kHz @ 1 watt @ 4Ω

SIGNAL/NOISE RATIO:

91dB @ 1 watt (A-weighted)
112dB @ full output (A-weighted)

FREQUENCY RESP.:

+/- 1dB (20-20kHz / worst-case @ 4Ω)

DAMPING FACTOR:

>500

RATED LOAD:

2.5-8Ω

INPUTS:

Balanced (accepts XLR, balanced ¼”, unbalanced ¼”)

OUTPUTS:

One pair / 5-way binding posts

TRIGGER:

Optional turn-on when an audio signal is detected

AC-INPUT:

From 100-264 VAC @ 50 / 60 Hz (automatically detected)

IDLE POWER:

~ 0.275 watts

POWER CONVERSION:

~ 80%

FRONT PANEL:

Blue LED when the PA-1 is on

REAR PANEL:

AC Rocker switch
IEC Power Cord socket
On / Auto Switch (On = AC via the rocker switch –
Auto = power on when audio is detected)

PROTECTIONS:

Excessive temperature, short circuits, DC offset at output, & input fault conditions. (The protection circuitry is totally transparent in normal operation. When any fault is detected, the output mutes. As soon as fault is removed, auto-reset returns amp to normal operation.

DIMENSIONS:

8.5” W x 1-7/8” high x 9” deep (unboxed, including feet, not including connectors)
8.5” wide x 1.75” high x 9” deep (unboxed, without feet)

WEIGHT:

3 pounds (unboxed) / 6 pounds (boxed)

PRICE:

$299 (each) USD

Company:

Emotiva

SECRETS Tags:

monoblock, power amplifier, Emotiva, class-d, audiophile, lightweight, balanced, budget, review, 2018, Power Amplifier Reviews 2018

LINKS TO OTHER MATERIAL ON THE SECRETS SITE:

On the advice of another audio reviewer (who shall remain nameless to protect the guilty), I once purchased several “pro” Class-D power amplifiers in succession from a major company in the pro-audio field. Although the amps were just adequate for home theater use, they failed miserably at providing the quality needed for critical home stereo listening. The Emotiva PA-1 amplifiers change that notion completely.

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The Emotiva PA-1 needs to be heard without the prejudices of previous Class-D experience. This is NOT your rock bandmate’s Class-D! The Emotiva PA-1 amplifier, in many ways, rivals some of the better audiophile power amplifiers on the market, and at a fraction of their prices. This statement is bound to stir up harsh criticisms (mostly from those who have never even heard this amplifier) but read on before you dismiss my claims.

And let’s also get the specifications issues out of the way – Many will read the specs and dismiss this PA-1 amplifier outright because it doesn’t measure as well as a Bryston or a Cary. I contend that this would be a mistake. Although I believe Emotiva’s specifications, I also strongly believe that the PA-1 amplifiers surpass (and by a wide, wide margin) the performance that one might expect when simply reading the amplifier’s specifications. And so forward into the breach:

Emotiva PA-1 Balanced Class-D Power Amplifier Circuitry

Design

The Emotiva Stealth PA-1 Balanced Class-D Monoblock Power Amplifier is an Emotiva in name only. The circuitry consists of a Bang & Olufsen ICEpower ASC300 module in an Emotiva case. There is no active Emotiva circuitry inside. That said, the Emotiva PA-1 Balanced Class-D Monoblock Power Amplifier is the least-expensive amplifier that you can buy that uses this particular B&O amplifier module.

 Emotiva PA-1 Balanced Class-D Power Amplifier Interior

I had the opportunity to interview Mr. Dan Laufman, co-owner of Emotiva, about the design of the PA-1 amplifiers. Dan indicated that the raisons d’être for the PA-1 amplifiers included:

First, Dan thinks that the Danish Bang & Olufsen ICEpower ASC300 module is the very first affordable class-D amplifier that’s good enough for audiophile use. Until now, class-D amplifiers, with their switching power supplies, have been predominantly used for public-address and sound-reinforcement. The few units designed for audiophile use were and still are very expensive.

Commercial-grade class-D amps are popular for their light weight, ruggedness, and cool operating temperatures. But their sound quality is unsuitable for home audio when compared to conventional class A and A-B amplifiers. The new B&O ASC300 module has finally crossed the threshold to significantly better sound quality, and Laufman considers it a true breakthrough product at its modest price.

Second, Dan thinks that Class-D amplification is the future of home audio amplification. Dan mentioned that multi-channel AV-gear (where many of the channels are used only for effects) could be a prime opportunity to use smaller and lighter class-D amplifier modules.

Third, Dan mentioned that having an established business relationship with B&O may allow Emotiva to partner with them on the design of some specific future class-D amplification modules. Dan hopes to offer these future custom Emotiva/B&O modules in a variety of Emotiva products.

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These tiny Emotiva PA-1 amplifiers weigh only three pounds each (that’s THREE POUNDS, I said…) and are approximately the size of a mid-sized paperback novel. This is about one tenth or less the weight of an amplifier of equivalent wattage with a traditional power supply. No more having to worry about the maximum weight limit of your equipment rack! There’s also no more worries about back sprains when having to move the amplifiers.

And because they run so cool, they can be either stacked, or installed in closed equipment cabinets without fear of significant heat buildup. This reduces the copious ventilation requirements that, for example, a class-A amplifier requires to avoid overheating. The cooler-running PA-1 offers yet another benefit – with less air passing through the amplifier to keep it cool, far less dust will be deposited on its heat sinks and circuit boards resulting in (theoretically) a far longer service life.

The amps offer fully-balanced circuitry with XLR input jacks or conventional unbalanced RCA connections via adapters (included in the amplifier box). Most of the time, I ran my amplifiers via the balanced inputs, but also used the unbalanced RCA connectors. I found no sound quality difference between the two.

 Emotiva PA-1 Balanced Class-D Power Amplifier RCA Adapter

When using the unbalanced RCA connectors, I discovered that my cable-box could be a source of hum, and Mr. Lonnie Vaughn of Emotiva was kind enough to inform me that a two-to-three prong plug adapter (available for 79 cents at Lowes or Home Depot) would immediately and very thoroughly solve the problem. Actually, Lonnie recommended just using pliers to cut the grounding plugs off the supplied power cords – the ground plugs on the PA-1 amplifiers are not required for safety grounding. With the grounds interrupted, the amplifiers were completely quiet. Even with my ears directly against the speaker drivers, I could hear no hiss, hum, or noise.

Emotiva PA-1 Balanced Class-D Power Amplifier Grounding Adapter

Note that if you’re using the PA-1’s balanced (XLR) input connectors, the amplifiers are dead silent despite the hum-inducing cable-box connection both with and without their power cables grounded.

Emotiva PA-1 Balanced Class-D Power Amplifier XLR Cables

I used the Emotiva PA-1 Balanced Class-D Monoblock Power Amplifiers in both “short interconnect / long speaker wire” and “long interconnect / short speaker wire” configurations. I heard no audible differences between the two. But since I had some short speaker stands in the closet doing nothing, I spent most of my review time with the PA-1s on stands immediately adjacent to the speakers with very short speaker wires (I liked the look).

Emotiva PA-1 Balanced Class-D Power Amplifier Amp Stands

Some attention needs to be paid to the Emotiva PA-1 amplifiers’ specifications. The total harmonic distortion (THD) seems high for a quality audio amplifier, but note that the distortion figures apply only at or near maximum output power. The average home listener uses less than one watt for “normal” listening and no more than about 10 watts for “really loud” listening, so the posted full-power THD figures for this amplifier are truly academic for home use.

The load rating also bears discussing. This is not the amplifier for driving ultra-low impedance loads (meaning less than 2.7Ω) to high volumes. Not only will distortion rise significantly, but the protection circuitry of the amplifier may trigger. This is not a worry for you unless your speakers meet any one of these three criteria:

  • Extreme low impedance (typical of many electrostatic speakers)
  • Extreme crossover complexity (larger and older Thiel loudspeakers are one example of speakers with complicated, multi-component crossovers)
  • Extreme low sensitivity (some older speakers have sensitivities in the mid-eighty-decibel range for one watt at one meter) – but this is an issue ONLY if you have both inefficient speakers and want to play at very high volumes for long periods of time.

Almost all (certainly more than 99%) of speakers currently on the market in 2018 are free of all these impediments and will work absolutely perfectly with the Emotiva PA-1 amplifiers.

Most conventional audiophile class-A and A-B amplifiers are what I call “arc-welders.” They will play happily into any load including near-short-circuits. The PA-1s can play into any reasonable load, but they’ll sound their best with loads between 4 and 8Ω despite remaining stable into loads as low as 2.7Ω.

Note that I’ve used both my Thiel 1.6 loudspeakers (nominally 4Ω but with some brief dips below that impedance) and the Sonus-Faber Sonetto VIII loudspeakers (also rated as nominally 4Ω) in this review. Both sounded amazing with the Emotiva PA-1 balanced Class-D monoblock power amplifiers. And when I say amazing…

Emotiva PA-1 Balanced Class-D Power Amplifier Thiel 1.6

Emotiva PA-1 Balanced Class-D Power Amplifier Sonus Faber

I listened to the Emotiva PA-1 Balanced Class-D Monoblock Power Amplifiers with a variety of music. In every case, the sound had a speed, depth, and dimensionality that is noticeably lacking with most amplifiers.

I had briefly loaned my review pair of PA-1 amps to my audio amigo, “Garbulky,” who tried them in lieu of his Emotiva XPA-1, Gen2 monoblocks. The XPA-1s are conventional Class-A/A-B amplifiers with huge power reserves. But despite the (much) better technical specifications of the XPA-1 amplifiers, the class-D PA-1 amps held their own on sound quality. Yes, there were some differences, but it would be hard to say that the XPA-1 (Emotiva’s previous flagship amplifier) was actually better.

Emotiva PA-1 Balanced Class-D Power Amplifier XPA-1

Garbulky’s speakers are Axiom Audio M80 models, also rated for 4Ω. He is currently considering replacing his Emotiva XPA-1 amplifiers with a set of four Emotiva PA-1s used in a bi-amplified array. I consider that a ringing endorsement of the audio quality of these tiny amps.

Emotiva PA-1 Balanced Class-D Power Amplifier Axiom M80

I also note that the 47kΩ input impedance of the PA-1 amplifiers is a blessing to those of us who want to use vacuum tube preamplifiers. An unbuffered tube-preamp output is typically of high impedance and not a good match for a solid-state power amplifier’s low input impedance (often as low as 10kΩ). However, that 47kΩ impedance is specific to the balanced inputs of the PA-1 amplifiers. The unbalanced input impedance is not specified.

There is one other observation that applies to these PA-1 amplifiers – their sound changes some when they’re warmed up. When cold, the amplifiers can exhibit a very slight touch of “class-D midrange emphasis,” but leave them on (their idling current of less than one third of a watt is trivial) and listen after they achieve thermal stability! The dynamics become slightly less prominent, but in exchange, you get a more three-dimensional soundstage and a more delicate treble.

Emotiva also sells rack mounts for their PA-1 amplifiers, in either one or two amps per plate configurations.

Emotiva PA-1 Balanced Class-D Power Amplifier Rack Mount 1

Emotiva PA-1 Balanced Class-D Power Amplifier Rack Mount 2

ASSOCIATED EQUIPMENT USED IN THIS REVIEW:
  • Mac Mini with jRiver Media Center 24 software
  • Emotiva Stealth DC-1 DAC/Preamplifier (in both balanced and unbalanced modes)
  • Mytek Liberty DAC (in both balanced and unbalanced modes)
  • Schiit Freya hybrid, balanced preamplifier (in both solid-state and tube modes)
  • Emotiva BasX A-300 power amplifier
  • ILP power amplifier (60 wpc / made in England)
  • Arcam AVR5500 AV receiver
  • Road Hog XLR cables
  • Audioquest RCA cables
  • Monster Cable in-wall speaker cable (2’ set only, unterminated)
  • Thiel 1.6 loudspeakers (6.5” two-way)
  • Sonus-Faber Sonetta VIII tower speakers
  • ATC Acoustics room treatments
Listening

Emotiva PA-1 Balanced Class-D Power Amplifier Morgan James

Morgan James “Sledgehammer” Peter Gabriel Cover

One of my guilty pleasures, lately has been the Morgan James YouTube cover of the Peter Gabriel song “Sledgehammer.” I never considered this song even remotely sexy until I stumbled across this cover. I am not normally a Morgan James fan. Yes, she has quite a vocal range, and her covers of popular songs

are suitably quirky and different, but “different” alone doesn’t always mean “better.” But THIS performance hits on all cylinders. The accompaniment stays out of the way and the background singers contribute to the impact of the song without becoming dominant or intrusive, while Morgan James’ facial expressions, body movements, and hand gestures emphasize the smoky feel of the song. In short, this is a masterful performance.

Through the Emotiva PA-1 amplifiers and the Sonus-Faber Sonetto speakers, her performance has delicacy, a clear sense of the boundaries of the recording venue, and clean power without distortion when the vocals demand it. In short, this just sounds REAL, despite YouTube offering significantly less than CD-quality audio.

Emotiva PA-1 Balanced Class-D Power Amplifier Jesse Cook

Jesse Cook “Matisse the Cat”

“Matisse the Cat” by Jesse Cook is one of those “demonstration cuts” that you’ll be playing for your friends to showcase the speed and slam of the Emotiva PA-1 amplifiers. When the percussion moves in, you get a startling sense of realism. The bongos (? – I’m not a drum expert) sound as though they’re in the room with you, and you get a sense of not only the drum heads but also the resonance of the open-bottom drum cavities.

I’ve played this cut through electronics that just sucked the life right out of the percussion, making it sound dull and muffled. But the PA-1 amps (bless their pointy little class-D hearts) take the prize for speed and openness with this clean, fast music.

Emotiva PA-1 Balanced Class-D Power Amplifier Norah Jones

Nora Jones “Lonestar”

My audio amigo, Garbulky, has a favorite cut called “Lonestar” by Norah Jones. The Gar likes to listen for the squeaking detail as the slide guitar’s strings are fretted. There is also some vibrato used in the slide guitar sustains that should be clearly audible. With the Emotiva PA-1 amplifiers, these details are not only clear and plainly audible, but also the amplifiers have enough speed to clearly define the fact that the sounds are actually coming from the slide guitar and not some other instrument in the mix.

Amplifiers with this level of speed and detail are highly unusual. The only other amplifiers that Garbulky and I have heard with these levels of definition are my custom-built 12-watt Heathkit tube monoblocks. Now the idea that a 12-watt tube amp could in any way compare with a state-of-the-art class-D monoblock is startling, but stranger things have happened (for example, once when I was young, Berma Sanchez actually kissed me). Who am I to blow against the wind?

Emotiva PA-1 Balanced Class-D Power Amplifier Lady Gaga

Lady Gaga “Dance in the Dark”

To look for the ultimate test of bass slam, I played Lady Gaga’s “Dance in the Dark.” It’s fully electronic, but when the apocalyptic drums enter the mix, any amplifier lacking in bottom end will have its shortcomings laid bare by this music. With both the Thiel and the Sonus-Faber speakers, the Emotiva PA-1 amplifiers were able to deliver the goods!

Not only did the PA-1s sound beefy, they maintained tonality and poise while doing so. I’ve had some amplifiers that just provided loud mush when asked to play low frequency material at volume. But the Emotiva PA-1s show both speed and slam enough to make program material with low bass enjoyable again and again.

Do the Emotiva PA-1 amplifiers have ANY audible shortcomings? As good as their bass is, I’ve heard better, but seldomly. Now I will admit that my experience with these amplifiers could be the result of fortuitous circumstance, with speakers that particularly like the B&O factory voicing of the amplifiers.

After all, I only tried the amps with two pairs of speakers. But my audio amigo, Garbulky, also tried these amplifiers with his Axiom speakers and formed much the same impressions that I did (and before I’d given him any hint of my opinions on the amps). I guess that “only” 140 watts could be a limitation for those who want “theater-level” sound-pressure-levels for their home theaters, but for stereo listening, these amps are da schizz.

Conclusions

Emotiva PA-1 Balanced Class-D Power Amplifier

The EMOTIVA STEALTH PA-1 BALANCED CLASS-D MONOBLOCK AMPLIFIER breaks the barriers between Class-D technology and “audiophile” sound quality. For their price, buy yours NOW!

Likes
  • Audiophile sound quality for $600 a pair!
  • Small, lightweight, and highly efficient
  • Rack mountable should you desire
  • Form factor matches the Stealth DC-1 DAC/Preamp
  • Fully-balanced circuitry
Would Like To See
  • Silver faceplate option
  • Included two-to-three power cord ungrounding adapters (or two-prong power cord)

I’ll lay it on the line – In my opinion, this is the best-sounding amplifier that Emotiva currently sells. I’ve not heard their fully-differential XPA-1 Gen3 amps (Emotiva’s new flagships), but I like the sound of the PA-1 monoblocks better than the sound of the XPA-2 Gen3 amp or the Emotiva BasX A-300 stereo amp (both of which I owned and was highly familiar with at the time of this review).

Have I ever heard a better-sounding power amplifier than the Emotiva PA-1s? Maybe – I once owned a McIntosh MC352 that I thought was absolutely superb, but not having it here for a side-by-side comparison, I can’t honestly say which would be best.

Emotiva PA-1 Balanced Class-D Power Amplifier McIntosh

Suffice it to say that I think the Emotiva PA-1 amplifiers are better than any others I have in my home and I’m strongly thinking about keeping them. Draw your own conclusions…