I write this review of the SW1X DAC IV Special while on a train gliding through the German countryside, listening to what I can only describe as guilty pleasure songs through a pair of second generation Apple AirPod Pro in-ear headphones. The experience I am having can only be described as meditative—there is little in the way of distraction from my writing—I appreciate the passing views and listening to music. Is there anything more mesmerizing than staring out a train window and letting the imagination run wild?

Some experiences in life just hit more than others. This is often due to their simplicity rather than in spite of it—and so, with simple music and the gentle rains of Hanover, I find all sorts of internal background noise has gone quiet. This is an experience that is almost impossible to have in hi-fi.

Words and Photography by Grover Neville

I suspect the reason for it to be so difficult is not so much the fault of any of the hi-fi equipment, but the focus and trappings of the setting. A room full of hi-fi components, that even resplendent in fanciful chassis, really is no substitute for the enormity of ‘out there.’ As humans, we are always and forever searching for whatever lies in ‘out there.’

I believe that the very best expressions of almost any pursuit connect us with a sense of the enormity of the world. A drive in a spectacular car on an amazing road or track, a meal cooked not just well, but perfectly, a painting that captures an emotion through a scene without being beholden to literal reality, or perhaps even a song playing through a hi-fi system rather than a hi-fi system playing a song. And the more we know, the more fleeting those senses of wonder and curiosity become. When we start asking ‘why does that happen?‘ the joy begins to bleed a little. Analysis is turpentine to the colors of awe.


SW1X DAC IV Special

Here I am, navel-gazing a little, and analyzing, well…a DAC (a digital-to-analog converter). Not quite so sexy sounding is it? I hope the presence shows off one thing however: nothing will ever quite be the same after you listen to any of the SW1X DAC models. The company, run by lead designer Slawa Roschkow and based in the UK, is one of the few makers of tube DACs that is doing things a little differently.

Rather than simply throwing tubes in the output stage of a typical modern DAC design, SW1X instead opts for a more interesting I/U stage. The exact implementation depends on model, for the DAC under review, the active voltage to current conversion uses a specially selected and very high quality transistor. The rest of the DAC is either tubes or transformers, with nary a shade of silicone in sight. And there is a serious amount of iron and tubes in this thing, including the signal output transformer de-coupled 6V6 output stage.

My review unit had no less than 7 tubes: one for rectification, two more tubes inside the DAC on the digital side—their function is oscillation or pace-making of the digital side of the DAC. Then two each for gain and voltage output, one of which was a 6V6 type power tube. When’s the last time you’ve seen something so beefy in a line-level component? Speaking of which, the balanced output of this review unit was listed at ~6V on the balanced outputs, and 3V RMS @-3dB for the single ended outputs. This certainly presented no problem for my pure tube linestage and integrated amplifiers. In any case, with all of the tube gear I used downward in the system chain the ~6V balanced output presented zero issues.

The Connections: SW1X DAC IV Special

In terms of functionality, the unit I reviewed did not have a USB input of any kind, supplying only AES/EBU and S/PDIF over Coax as inputs, though a VSB or valve-based USB module is available from SW1X, separately or integrated into certain models. Other than this input omission in the DAC IV Special, functionality of the review unit was straightforward—turn it on and turn the volume up. Simple as can be.


The Sound: SW1X DAC IV Special

It would be somewhat incorrect to say that the SW1X DAC IV Special just converts a digital signal to music—rather the experience of listening to the DAC IV Special is more that you are experiencing music through the source that is the DAC IV Special. There is a notable focus and density to the midrange that casually dismisses with audiophile notions or dispositions. This special DAC is made for a music listening experience that feels like Technicolor 5K UHD looks.

Compared to every other DAC I’ve had on hand during the review period, all of which were some kind of solid state—whether R2R ladder, chip-based, with op-amp or discrete output stages—there was a focus and immediacy of dynamics in the SW1X DAC IV Special, especially to the midrange that was simply unparalleled. I’ve also had a recent discussion with the chief designer of a very well known (and famous) tube amplifier manufacturer who expressed the opinion that, ‘if the midrange isn’t right, it’s hard for me to care about the rest of it.’ A statement of which I couldn’t agree more to.

In the case of the SW1X DAC IV Special: the midrange is simply the best I’ve ever heard in a DAC, and more closely approximated the sense of pleasing dynamic liveliness as vinyl playback. Now, that is not to say it possesses the characteristic curve, lathe-specific imprints or surface noise of vinyl, but from a dynamic liveliness, midrange focus and textural density standpoint, my level of satisfaction was elevated closer to that analog set of characteristics than I’ve experienced with any but the most exceptional vinyl playback.

The low end and top end are essentially invisible—in the sense that rather than having a characteristic tightness, looseness or a particular characteristic that would draw one’s attention, they simply sound correct. Or at least like whatever acoustic principal is correct based on your chosen loudspeakers. The top end is smooth and the low end is present and provides a substantial foundation, with perhaps an overall hint of warmth to the ears of those accustomed to inexpensive modern chip-based dacs. To my ears it could only be described as right.

Our INDULGR Audiophile playlist includes 600+ tracks perfect for auditioning high-end audio gear, and was curated by our team of editors.

Besides drawing the ear specifically to the midrange, the overall effect of this style of presentation was one of exceeding naturalness and deep detail. Typically, a forward or boosted treble presentation is misinterpreted as being too forward, but here I was able to easily pick out layers and experience details of presentation at a deeper level than with lesser DACs.

Though, I was also drawn to experience this information in a musically relevant way, and I found myself much more likely to notice subtleties which contributed to the artistic whole, rather than those fun but often creatively boorish ‘background chair squeak’ noises most audiophiles fuss over. None of that audiophile squabble matters in the end—a clock radio can convey the basic musical message of most popular music. An audiophile hi-fi system which draws one’s attention only to details without exposing the whole picture has failed no matter the level of perceived resolution.


The Conclusion: SW1X DAC IV Special

This then is the conceit of the SW1X DAC IV Special—if you are looking to escape the form of acquisition and analysis that accompanies so much of the mainstream audiophile experience, here is an answer. While this will not suit the audiophile who prizes the dry, bright or hard sounding digital, or is chasing some fantasy of ‘accuracy’ the sonic perspective the DAC IV Special offers had me listening to my system every day without a miss. This has not happened for several years, and I feel as though I’m experiencing the wonder and joy of the novice once again. Not from the perspective of an audiophile, but merely from the position of a professional musician with a hi-fi system.

This SW1X DAC IV Special takes me places typically reserved for train windows, rainy days, and the mornings after a birthday party. If emotional engagement is the metric, the SW1X DAC IV Special is quite simply the best digital converter for hi-fi I have ever heard, and I will be purchasing an SW1X DAC in the near future.


UPDATE: As of Monday, August 21, 2023 a few minor changes were made above to correct the model designation and specific build details.
Our sincerest apologies, and thank you to early readers.

About the Author

Wanderer, Wonderer, Musician, Actor

Grover Neville resides in sunny Los Angeles, California, and is a graduate of the Oberlin Conservatory of Music where he studied music and creative writing. After graduating he pursued a freelance career in audio, and professional research in the fields of Auditory Cognition, Psychoacoustics, and Experimental Hydrophone Design. He is a native of Chicago, Illinois and previously did work there as a mixing and mastering engineer, working in music genres such as Avant-garde Classical and Jazz.

As a transplant to Los Angeles, Grover still works in the music industry, but now adds the video game and film industries to his calling. He is actively pursuing a career as an independent musician, composer, and producer. He previously contributed to Innerfidelity, Audiostream, and Part-Time Audiophile—before becoming an editor and co-founder of INDULGR magazine.


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