Note: Measurements can be found through this link.

It’s not often that I ask questions of a manufacturer about their product and don’t get detailed answers, and it’s downright rare that questions about technical details are met with the equivalent of, “I’m not going to answer that.” I understand that the high end is a competitive space full of companies big and small, all trying to appeal to a fairly small pool of buyers. But asking someone to part with several thousand of their hard-earned dollars for an audio component while refusing to tell him or her what’s inside it is a bit nervy. If Elon Musk debuted a new Tesla automobile but refused to give any details about its motor or batteries, I can’t imagine that consumers -- let alone Tesla’s shareholders -- would respond warmly.

Exogal Ion

But that’s what the folks at Minnesota-based Exogal did when I inquired into the guts of their new Ion PowerDAC ($6850 USD, $7350 as reviewed). Following on the heels of the Comet DAC, which Jeff Fritz reviewed in mid-2015 on SoundStage! Ultra, the Ion is only Exogal’s second product -- ever. Nor is my comparison with Elon Musk terribly far off: Exogal’s founders include Jim Kinne and Larry Jacoby, the founders of Wadia Digital, one of the early pioneers in digital audio. Promising.

The Ion

Exogal’s Ion is a power amplifier ($3850) that can be used only with Exogal’s Comet digital-to-analog converter ($3000). The Ion will not work with any other company’s electronics. Connected via Exonet, Exogal’s proprietary digital connection, the Ion and Comet together comprise the Ion PowerDAC ($6850). Exogal also offers for the Comet a power supply upgrade; this costs $600 if purchased separately, or $500 when bundled with the Comet DAC in a package called the Comet Plus. For this review, Exogal sent me a Comet Plus and an Ion, total retail price $7350. It should be noted that existing Comet owners can add an Ion to his or her system without any fuss simply by bringing the Comet’s firmware up to date.

The Ion’s and Comet’s cases have identical dimensions of 11.5”W x 1.9”H x 7.5”D and nearly identical appearances. The Ion weighs 9 pounds, the Comet 9.2 pounds. (The power supply upgrade measures 6"W x 2.25"H x 6.5"D and weighs 2 pounds.) The brushed-aluminum finishes of the Ion and Comet look quite nice, and wrap around the front and each side of both models. The top of the Ion also gets the aluminum treatment, while the Comet receives a robust finish of hard acrylic with a contrasting black underlay. The aluminum top panel of the Ion power amp features Exogal’s logo, which looks like planets orbiting a star or electrons spinning around the nucleus of an atom, like an ion. The only detail on the Ion’s front panel is a single, centrally mounted LED that indicates the unit’s status, as explained anon. The Comet, meanwhile, has only a small, monochromatic display that’s terrifically difficult to read from more than a couple feet away, and even then, only the volume level is legible. I found myself having to stand almost directly in front of the Comet in order to see which other settings I’d selected. With no buttons of any kind on either case, the Ion PowerDAC is small and minimalist.

Exogal Comet

I strongly recommend reading Jeff Fritz’s review for more information about the Comet DAC -- it’s a clever and flexible product. As for the Ion, here’s what Jeff Haagenstad, CEO of Exogal, told me -- and didn’t tell me -- about its innards:

We actually won’t discuss the details of our design because it’s literally been simmering in Jim [Kinne’s] head for 25 years and honestly it’s our “secret sauce.” The technology to make it work has only become available in the last few years and it was so difficult to develop that we were 18 months late to market after we announced it. Controlling analog power in the digital domain is really difficult. You cannot underestimate how badly Electromotive Force (EMF) wants a rising voltage to continue rising and a falling voltage to continue falling. It took us those 18 months to work out how to control that EMF and during that time we fried a lot of Ion prototypes, and a lot of speakers and dummy loads. I will tell you that the technology is not based on [pulse-width modulation] in any way. PWM is just not capable of giving you the lightning-fast transient response that gives the Ion its level of performance.

Haagenstad’s comments about pulse-width modulation resulted from my pressing him about the nature of the Ion’s circuit. The amp is fully sealed, with no venting whatsoever, so I assumed that it was a high-efficiency class-D design. While that still seems likely, the only things we know for sure about what the Ion is what it’s not, and for now that seems limited to: It’s not based on PWM. Information about the power supply was equally unforthcoming. “Nope. Secret sauce,” was Haagenstad’s reply. Alrighty then.

Exogal Ion

All I know about the Ion is what Exogal specifies in its ads and on its website: It generates 100Wpc into 8 ohms or roughly 150Wpc into 4 ohms, and remains stable down to 2 ohms. Its output current peaks at 10 amps. Other specs include a frequency range of 5Hz-22kHz, total harmonic distortion of 0.03% at 1W at “all frequencies into 4 ohms” (presumably within the amp’s previously mentioned frequency response), a signal/noise ratio of greater than 105dB A-weighted, and a damping factor of more than 100 into 4 ohms.

Exogal’s target market for the Ion is those who appreciate high-fidelity sound and are willing to pay for it, and who want a consolidated, progressive musical experience. Exogal has no interest in making products with tailored, euphonic sound; all they want to do is reproduce recordings to sound as they were originally mastered. “We don’t think it’s our place to impose our biases on a listener’s experience,” Haagenstad explained.

Exogal heartily believes that affordable and profitable audio components can be manufactured domestically; it’s a source of pride to them that all of their products are made in the USA.

Connections, setup, and use

Unpacking and setting up the Comet and Ion was painless. When, per Exogal’s directions, I placed the Ion directly atop the Comet, I discovered that they are perfectly symmetrical with each other, and took note of the various inputs and outputs on display. The Comet features a miniplug, wall-wart-style power connector; if the Comet is used without its power supply upgrade, aftermarket power cords are out of the question. I was using the upgrade, however, which has an IEC inlet to permit the use of any power cord you’d like, and a captive cord to power the Comet. This DC umbilical is also upgradeable, according to Exogal.

The Comet’s inputs are: unbalanced analog (RCA), AES/EBU, optical, asynchronous USB, and S/PDIF. Exogal includes both unbalanced (RCA) and balanced (XLR) outputs, as well as a 1/4” headphone jack, this last on the right side panel. PCM signals up to 24-bit/192kHz are accepted at all inputs except the TosLink, which is limited to 96kHz. The USB input can handle up to 32/384 PCM, as well as DSD64 and DSD128. There are also a trigger connection, a serial port, a Bluetooth antenna port, a 2.1A USB charging port, and Exogal’s Exonet input and output, for connection to the Ion.

The Ion’s rear panel has the same high-quality, five-way binding posts I’ve found on many other top-shelf amplifiers, as well as a serial port, a USB control port, an Exonet input, and a four-pin XLR plug for power. The USB port makes it possible to integrate the Ion into automation systems; the serial ports on the Ion and Comet are intended for use in firmware updates.

Exogal Ion

I wired the Comet and Ion together with the included Exonet cable, plugged the Comet into its power supply upgrade, and the Ion into its own brick-sized external power supply (included). My source component was my trusty MacBook Pro laptop running Roon, which I connected to the Comet via the latter’s USB input using a DH Labs Silversonic USB link. I primarily used the Ion with my Monitor Audio Silver 10 speakers, but also pressed into service Dynaudio’s Emit M10 bookshelf speakers, also reviewed this month, to hear how the PowerDAC would cope with a less efficient load.

Using the Ion PowerDAC I found to be not as intuitive as your run-of-the-mill DAC-integrated, or as the similarly priced Devialet 130 Pro. This was due in large part to the fact that the Ion has computer circuitry that needs to boot up when first configuring the PowerDAC. The LED on the Ion’s front panel flashes in various colors, depending on the Ion’s status: red on initial setup, yellow for Standby, and green when it’s ready to play music. To get to green, I needed to use Exogal’s cheap but fully functional plastic remote control (included) to select the Comet’s input and output (headphone out, analog out, or Exonet). I selected USB and Exonet, respectively. Two quirks of the unit are that it’s always muted on turn-on -- this is nondefeatable -- and that the Mute function has two levels. Pressing the remote’s Mute button once results in reduced mute (-20dB), in which mode the sound level drops to a whisper; press Mute twice for the silence of full mute.

Exogal’s Android/iOS app worked perfectly. After I’d plugged the little Bluetooth antenna (included) into the Comet’s rear panel, the iOS app on my iPhone quickly found the Ion PowerDAC, which proved super-responsive to commands for On/Off, Volume, and Source. It’s not the most elegant or feature-filled app, but it worked well throughout my time with the Ion PowerDAC.


Most solid-state amplifiers I’ve heard in the past few years have been tonally neutral. In fact, I’d go so far as to say that most well-designed solid-state amplifiers sold in the past ten years can boast a frequency response that is stupidly flat. You might expect that these amps would all sound alike, but I’ve found it easy enough to hear differences among them. Every circuit architecture has its pros and cons, and an amplifier’s interaction with a given loudspeaker can be a bit of a crapshoot. The Exogal proved a harder nut than most for me to crack.

Exogal Comet

I’m big on first impressions. It’s a bit unnerving for me when I can’t pin something or someone down quickly; it’s about the only thing in life at which I’m half decent. The Ion PowerDAC took me quite a while to get a read on. It was highly revealing, but not in the stereotypical solid-state way of “Listen to how immaculate and crystal-clear I sound!” It was also musical, without tainting recordings with tonal colorations. Another word I associate with the Ion PowerDAC’s sound is smooth, but it would be unfair to describe the Ion’s overall sonic character in that way.

Take “Ophelia,” the radio-friendly hit from the Lumineers’ Cleopatra (16/44.1 FLAC, Dine Alone) that I can’t get out of my head. Lead singer Wesley Schultz’s folksy delivery was smooth and full-bodied, much of that owed to the recording itself, which lends the tune a homey, unfiltered feel. With the Ion pulling the strings, the Lumineers felt right at home in my system. The band’s performance was warm and intimate, with Schultz’s voice, the accompanying piano, and the percussion all taking on a slightly rounded, analog character. I might even call it tube-like euphony, minus any of that phrase’s negative connotations. The sense of upper-midrange zip and treble urgency that I’d expect to hear from a top-flight class-AB amp were conspicuously abbreviated here, though it would be presumptuous to label the Exogal’s reproduction of the Lumineers’ latest and greatest somehow deficient. It’s simply that dynamic contrast was not the Ion’s calling card.

Exogal Ion

To test the Exogal’s athleticism, I turned to a genre that any fellow millennial would be proud to play: dubstep. The elusive, London-based Burial burst on the scene in 2006 with his eponymous debut album, which combines several strains of electronic music into a dark, brooding, thoughtful whole. His second album, Untrue (16/44.1 ALAC, Hyperdub), released the following year, is more focused and polished, and earned considerable critical acclaim. It’s a hypnotizing menagerie of contorted vocal samples, atmospheric effects, and ambient noise that coalesces into something highly stylized yet oddly familiar -- if ever there was music to get lost in on a cold, dark, rainy day, this is it. Burial’s pitch-shifted voice in “Archangel” was rendered cleanly and clearly by the Ion PowerDAC, with a strong central image and an abundance of color and texture. The song’s powerful bass line was extended, if a touch soft. The soundstage was deep, though I couldn’t hear through it straight to the back of the aural tapestry with the ease I’d hoped for. The timbral balance of the Exogal’s reproduction of this track was exceptional, but it couldn’t replicate the spatial illusion quite as well as I wanted.

Wanting to push some boundaries, I cued up the punishing “No Time for Caution,” from the orchestral score for the film Interstellar (24/44.1 ALAC, WaterTower/HDtracks), composed by my namesake, Hans Zimmer, who makes liberal use of the Harrison & Harrison organ of Temple Church, London. In this track he does his best Philip Glass impression, beginning slowly but quickly increasing in tempo and power. However, what’s first heard, in the distance, is the quietly urgent singing of a women’s chorus that swiftly makes way for cautionary drums and the organ, which push “No Time for Caution” over the edge into progressively more violent sound. The Ion PowerDAC accurately conveyed the scale, flow, and majesty of this standout effort by Zimmer, delicately jockeying between the finesse needed to capture the simple piano melody teetering at the left rear of the orchestra, and the force needed to re-create the massive bass swells that conclude the piece. The treble extension in the reverberations of the organ’s sound in the historic church was smooth, if a touch polite.

Exogal Comet

That album’s closing track, “Do Not Go Gentle into That Good Night,” is a haunting spoken-word collaboration among key performers in the film: John Lithgow, Ellen Burstyn, Casey Affleck, Jessica Chastain, Matthew McConaughey, and Mackenzie Foy. The Exogal was unmoved, and the various approaches of these actors were fascinating to listen to. Lithgow’s and Burstyn’s decades of experience and deep, weathered interpretations lent an authenticity to Dylan Thomas’s famous villanelle that contrasted with Affleck’s boyishness, Chastain’s jocular cadences, and McConaughey’s velvety Texan flow; and Foy’s higher-pitched, adolescent voice gives this coda to the film a feeling of unfiltered authenticity. The Exogal was excellent at relaying midrange nuances in all these voices in an uninhibited, totally neutral fashion.


I’ve found Hegel Music Systems’ H360 ($5700) to be a high-water mark for power, performance, and utility -- which is why, for the past year, it’s been my reference DAC-integrated amp. The H360 is also distinctly old-school in approach, generating 250Wpc into 8 ohms via a class-AB circuit, a traditional preamp stage, and an excellent built-in DAC. It lacks the Exogal’s headphone output and dedicated software application, but makes up for it with a much nicer remote control and about twice the power output. Despite both the H360 and the Ion being highly neutral, their sonic profiles differed in fairly dramatic ways. The Hegel exhibited greater dynamic contrast, with an extended top end that made its sound more spacious, allied with tighter, more visceral bass slam. The Exogal projected a soundstage with a tad less depth but more florid bass output, and lacked the Hegel’s pomp and circumstance.

Track after track, the H360 seemed to offer more jump factor, its midrange seeming to emphasize the upper vocal registers; the Ion remained demure and dignified in its interpretation of my music, always sounding ruler-flat. Imaging-wise, I heard greater definition and precision from the Hegel, whose more open and exacting sound I preferred -- but I know many audiophiles who will favor the Exogal’s more intimate, perhaps more honest reproduction of the midrange. The Exogal’s smoothness was alluring, even if it made for slightly less distinct imaging of the various voices in “Do Not Go Gentle into That Good Night.” In appearance, however, the Ion is the more attractive and well built of the two, its clean aluminum lines and smaller size making it more fetching than the H360’s folded-metal housing and bright blue LED display.


Exogal’s Ion PowerDAC is a novel, forward-thinking concept. It partners a high-performance DAC with a multitude of inputs, including traditional analog inputs and a dedicated headphone output, with a proprietary amplifier in a well-tailored all-in-one package. While its remote control and small monochromatic screen leave a bit to be desired, its mobile app worked perfectly. Considered in tandem with its strong sound quality -- its terrific tonal neutrality makes it something of an aural chameleon -- Exogal’s Ion PowerDAC should be strongly considered by anyone who’s in the market for a comprehensive stereo-electronics solution.

. . . Hans Wetzel

Associated Equipment

  • Speakers -- Dynaudio Emit M10, KEF LS50, Monitor Audio Silver 10
  • Earphones and headphones -- NAD Viso HP50, Pryma 01, PSB M4U 4
  • Integrated amplifiers -- Devialet Expert 130 Pro, Hegel Music Systems H360
  • DAC-headphone amplifier -- Oppo Digital HA-2SE
  • Source -- Apple MacBook Pro running Roon
  • Speaker cables -- DH Labs Q-10 Signature, Dynamique Audio Caparo
  • Analog interconnects -- Dynamique Audio Shadow RCA, Nordost Blue Heaven LS XLR
  • USB cable -- DH Labs Silversonic
  • Power conditioner -- Emotiva CMX-2

Exogal Ion PowerDAC
Price: $6850 USD; power supply upgrade, $600 USD; $7380 USD if purchased together.
Warranty: Five years parts and labor.

4657 Aspen Ridge Circle
Eagan, MN 55122
Phone: (651) 964-0698