SPL Phonitor X Headphone Amplifier

Power Galore

Equipment report
Solid-state preamplifiers,
SPL Phonitor X
SPL Phonitor X Headphone Amplifier

My first and last impression of the Phonitor X was one of unfettered power and control. Whether coupled to the new, lightning-fast Focal Utopia headphones or the venerable Grado RS-1 on-ears, the Phonitor X exerted a level of finesse that put it on par with the top echelon of headphone amplifiers, tube or solid-state, designed to handle difficult-to-drive headphones.

In the past I have not been impressed by the vast majority of headphone amplifiers’ implementations of “crossfeed.” This is usually a setting or collection of settings that adds some amount of right-channel information to the left, and left-channel information to the right. Even SPL’s Phonitor II, which had even more matrix and crossfeed setting options than the Phonitor X, did not generate a “better” soundstage implementation for me. But with the Phonitor X, I did find that with some material the matrix and crossfeed offered a wider, deeper, and more spatially precise soundstage. But the sonic changes were not all universally benign. The matrix and crossfeed circuits also introduced some shifts in the harmonic balance of all the headphones I used with them. With the crossfeed and matrix settings engaged, the lower midrange lost a bit of harmonic complexity and richness, while the upper midrange gained a bit of additional lucidity. But with some headphones that tend to be slightly warm-sounding with an overly rich lower midrange, such as the AudioQuest NightHawk or Audio Technica ATH-W3000ANV, I felt the harmonic changes were generally beneficial. Unlike other headphone amps where matrix and crossfeed stayed off after an initial audition, with the Phonitor X, I found that I often preferred listening with those settings engaged.

The Phonitor X has very little that could be called a prevailing or unique sonic character. Its overall harmonic balance is very much like what I hear from other high-quality solid-state headphone amplifiers such as the Audeze Deckard, except that, unlike headphone amplifiers with a 30-volt maximum output, the Phonitor X delivered unrestricted dynamic contrasts that pushed whatever headphones were attached to it to greater sonic heights. These greater dynamic swings were most obvious on my own live concert recordings. On quite a few I found that the Phonitor X expanded their dynamic range to the point where I needed to turn down my usual level settings to prevent the loudest passages from getting oppressively loud. Also unlike many headphone amplifiers whose sonic character changes during the such passages, the Phonitor X’s overall balance and control never shifted regardless of how near the VU meters approached 0dB. When I heard changes or additional hardness during dynamic peaks, it was coming from someplace other than the Phonitor X.

Bass extension and control through the Phonitor X were exemplary. Coupled to the new Focal Utopia headphones, “Dracula” by Bea Miller had more low-bass “oomph” than through other headphone amplifiers, such as the Moon Audio Inspire Dragon HPA-1, which demonstrated slightly less control of the bottom octaves. Listening to DJ Snake’s “Too Damn Low,” I was impressed by this combo’s ability to turn sub-bass into something melodious. For bouncy bass try Bastille’s “Good Grief” where the Carol Kaye-ish bass line came through loud and clear even during the thickly layered choruses.

When used as a preamplifier the Phonitor X proved quiet and capable of driving longer line-level connections with ease. I used the Phonitor X with a variety of amplifiers including the First Watt F7, the Bel Canto REF600M, and the NuPrime ST-10. In every case the Phonitor had an abundance of additional gain—I rarely turned the volume control past ¼ turn. Also the Phonitor X was dead quiet with all the amplifiers I connected it to. Its sonic character was clean, clear, and dynamic. While not quite as transparent and dimensional as using the Mytek Brooklyn connected directly to the power amplifiers, the Phonitor X used as a preamplifier added only the slightest amount of additional electronic haze to the aural picture.

With a $2800 budget you have a plethora of headphone amplifier/preamplifier options. Of course, I have not heard them all, but among those I have heard the Phonitor X offers a unique set of features coupled with outstanding performance. I still consider the Audeze Deckard headphone/preamplifier ($699) a superb value, but if you need a balanced line and headphone connection it isn’t going to work for you. When I compared the Deckard’s single-ended headphone output with the Phonitor X’s using the Focal Utopia headphones with their stock, single-ended cable, I was impressed by how similar the two headphone amps sounded, both in tonal balance and in soundstaging. But when I compared the Deckard’s single-ended output with the Phonitor X’s balanced output (using a balanced Moon Audio Silver Dragon cable), the balanced connection bettered the single-ended one with a slightly larger soundstage and better micro-dynamics.

The Moon Audio Inspire Dragon IHA-1 single-ended headphone/preamplifier ($1599) proved to be the Phonitor X’s sonic equal, but it has a different set of ergonomic strengths. Sonically the Moon has a more three-dimensional presentation and a larger soundstage, but it doesn’t have the Phonitor X’s rhythmic drive or low-bass control. And while the Moon has a balanced output for headphones, it lacks balanced input or output line-level connections, both of which the Phonitor X does have. Last point of difference—the Moon has only one single-ended output while the Phonitor X has two, one balanced and one unbalanced.

I returned the review sample of the NuPrime DAC 10-H DAC/preamplifier ($1795) before the Phonitor X arrived, so I did not have an opportunity to compare the two directly. I did find the DAC 10-H much harder to use via its front-panel controls. In fact, I relied heavily on its remote for all functions. Conversely, the Phonitor X front panel is easy to navigate by feel only. Also the NuPrime DAC 10-H’s deeply inset balanced XLR connection was not as easy to use as the flush-mounted connection on the Phonitor X. Lastly the Phonitor X has mechanical VU meters, which are, as we all know, really, really cool.

As I mentioned earlier, I can’t imagine a situation where the Phonitor X could run out of power and not be capable of optimally driving any pair of headphones. Sonically the Phonitor X offers a suave delivery with extremely good bass control and extension. When you add its well-laid-out controls and options, you have a product whose ergonomics are as good as its technical abilities. If you’re in the market for a headphone amplifier and preamplifier that can serve as a reference in either a dedicated headphone or nearfield audio system, the Phonitor X should be among your options. It is solid and well designed, and you can get it in red. What’s not to like?

Specs & Pricing

Type: Solid-state analog headphone amplifier with optional DAC card
Outputs: One pair balanced XLR, one pair unbalanced RCA
Output power: 2 x 3.7W (into 120 ohms)
Dynamic range: 135.5dB (HP), 136.3dB (Line)
Dimensions: 10.95" x 3.94" x 11.19"
Weight: 9.5 lbs.
Price: $2799

Audio Plus Services (U.S. Distributor)
156 Lawrence Paquette Industrial Drive
Champlain, NY 12919
(800) 663-9352

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