SPL Phonitor XE Headamp/DAC Review

I mused a while back in my Ether 2 review what it meant for something to be ‘the best,’ at what it does. Moving beyond the, frankly, intellectually lazy idea that ‘it’s all subjective,’ I came to the conclusion that with regards to audio, ‘best’ is something that exists as a topic of conversation between the zeitgeist and manufacturing capabilities of the time.

As with all people however, we learn and change. I’m no longer convinced the equation is quite that simple, or at least I’d like to complicate the idea I put forward in that review by re-examining the criteria or personal taste that I left out of that piece. I realize of course, that the zeitgeist itself is subjective, but how can we define a product that is tightly put together, captures our ears, and yet has not necessarily captured the ears of the collective discourse?

Perhaps in a certain sense, this is all predicated on the idea that personal audio hi-fi is, and will forever be, an exercise in chasing the flavor of the month.

Navel-gazing aside, I’m of the opinion that the headphile realm is transitioning from the ‘thrill of the chase’ phase of our relationship with the hobby, to more of a ‘nesting and looking to the future,’ phase. I consider this review very much in-line with that perspective on things at least, because the product I’m reviewing today is not new or surprising. It never really had its time as flavor-of-the-month, and while I certainly wouldn’t say it’s underrated, I would say it’s a bit of a dark horse in my mind, something that deserves a second look, a little more attention or even just a little love when we make our shortlists of exceptional gear.

SPL’s Phonitor line is unusual in that it is one of only a handful of products that truly positions itself as both a professional tool and a consumer-ready luxury. The front panels of the entire lineup of the Phonitor series display SPL’s studio heritage with the kind of discrete flamboyance you might find in formal side of Andy Warhol’s wardrobe. Defeatable VU meters, loads of knobs and slick silver SPL logos adorn the front panels, which come in your choice of very classy red, silver or the loudest black I’ve ever seen in an electronics product. SPL has long been known for making distinctive looking and sounding gear, even in the pro world where designers generally have a more adventurous sense of design than in hi-fi, and the Phonitor lineup is among the classiest and most refined looking of their designs. For the average headphone audiophile this translates into something tastefully left of center on the design scale. It’s a beautiful piece, but it does draw more attention to itself than the black and silver boxes you may be used to from strictly hi-fi focused companies.

The back panel reveals SPL’s dedication to the Phonitor lineup being a consumer product however. There are a variety of configurations you can get, some with preamp outputs, DAC inputs, balanced and single-ended headphone outputs and more. In this case, I was sent the XE, which has a built in AKM4490-based DAC, and trades the preamp functionality for switchable front and back headphone outputs, both single-ended and four-in balanced. The different configurations carry various price tags, with some, such as the very basic, featureless Phonitor E amp dipping down to $1,499 USD, while some such as the X, with the optional DAC included, can rise as high as $2,799 USD. In the middle is the professionally-oriented Phonitor 2, which skips the DAC for two sets of XLR inputs, one set of XLR outputs, a single set of RCA inputs, and has only a single-ended output on the front, for a tidy $1,699 USD. More on the different versions later.

The optional DAC module in my unit as a $700 USD price tag, and will do up to 32-bit/786kHz PCM as well as DSD up to DSD256, and takes AES, Optical, Coaxial or USB digital inputs. SPL emphasizes that all of their analog stages are built around 120V rails, a technology they’ve dubbed VOLTAiR, the idea being to provide maximum headroom at all points along the analog signal path. Whatever you think of that, it’s a technology that’s found its way into almost all of SPL’s technology and can be considered part of their ‘signature’ when it comes to circuit design. My experience with SPL’s professional gear is that they often have a distinctive openness in the treble and plenty of headroom, and the Phonitor series is no exception.

Before addressing sound though, I would be remiss not to mention the other technology SPL advertises as key to the Phonitor series amplifiers, and in fact is the namesake of the products themselves. The Phonitor matrix is SPL’s take on crossfeed, controlled by two knobs, one of which selects between four different phase degrees ranging from 22 to 55, the other of which has selects between six crossfeed settings. The ‘Angle’ control adjusts the inter-aural time delay, affecting the perceived angle of sound sources, while the ‘Crossfeed’ control increases or decreases the interaural level difference, all of which have been tuned specifically to approximate certain kinds of room reflection and absorption characteristics. Both settings are corrected for what the manual describes as the head reflecting and absorbing sound in a non-linear way.

SPL includes a very helpful chart detailing every possible combination of the two settings and giving specific numbers for the exact inter-aural time and level values as well as the perceived phase angle given for any combination. While the details will be of interest only to audio science nerds and particularly obsessive engineers - like myself - the big takeaway is that the two controls interact fairly significantly. Set the angle high and the crossfeed low and you’ll get a similar but subtly different sound than setting the crossfeed high and the angle low. There’s a huge amount of tweaking that can be done here, but I’ll note that the actual results are very much on the tasteful and conservative side on SPL’s part. It’s really not possible to make the matrix sound bad, and the network, perhaps by virtue of both its simplicity in focusing only on crossfeed, or it’s totally analog nature, sounds quite subtle. There is no artificial phantom image as you might get from contrived 3D audio schemes or head trackers, and while the effect will not drastically change the imaging performance of most headphones, it does add a subtle stereo blend which I found quite pleasing. This was one of the very few times I’ve found a processing setting on a piece of consumer gear and not felt the need to defeat it after long periods of listening. It’s not dramatic enough for me to miss it on other headphones, but I leave it on whenever I listen to the SPL, which is saying a lot when it comes to headphones, which tend to reveal most processing’s artificiality for what it is, relatively quickly.

SPL Audio

Simply Nobody's picture

May be Grover could also review the Chord Hugo2 and the Hugo TT2, and tell us how they work with various headphones/in-ear phones :-) ..........

Grover Neville's picture

I've had good experiences with chord gear, but have, perhaps unfairly, never reviewed it as it's quite expensive. Perhaps I will give it a second look!

Simply Nobody's picture

One more for Grover to review ....... iFi Audio Zen DAC/headphone amp, $130 :-) .........

Grover Neville's picture

Just got sent one of these by iFi so keep your eyes out for the review!

Simply Nobody's picture

Grover could also review the new KLH Ultimate One headphones with Beryllium drivers, under $500 :-) ........

Simply Nobody's picture

As a reference (not as a review), Grover could listen to Focal Arche headphone amp and Focal Utopia Beryllium headphones, when reviewing the KLH Beryllium headphones :-) .......