The primary devices being tested:

  • Linear Solution switch
  • SOtM modified switch
  • SOtM tX-USBultra
  • SOtM sMS-200
  • SOtM sCLK-OCX10
  • Intel NUC

Over the past few months, I used the SR4 (and SR7) to power various parts of my audio chain. During that time, I’ve written over 100 pages of notes and have consolidated my findings. There were a few themes I discovered during my listening sessions. Holistically, everything the SR4 powered was instantly elevated in a multitude of ways. It imparted a sense of purity and cohesion that I think most try to find in their DACs, amplifiers, and other equipment. The sonic gains were not subtle across all tested components and were particularly high with the SOtM tX-USBultra.

Even prior to break-in, the SR4 exhibited finesse, fine levels of gradations (especially of low-level cues), and exquisite dimensionality. In its fresh state, it outperformed every power supply I had on hand – by a sizeable margin. The differences were immediate and profound. This only improved over time, especially after the first 150 hours. While most high-end power supplies have a “character” to them, the SR4 skips this step and goes straight for truth.

In ways, it almost sounds “impossible.” I’ll explain.

I usually use recordings as reference points but after sorting out the notes, I felt it made more sense to provide holistic impressions.

The first thing you’ll notice is how realistic the soundstage is presented. Aside from width and incredible depth reproduction, the pieces of the music are layered, outlined, and arranged with pinpoint precision. To me, it redefined what “holographic” means. To put it bluntly, the other supplies, which are fantastic, sound flat and slightly congested in comparison. The SR4 displays a “layered shape” with the lifelike cohesion of vocalists, stringed instruments, percussions, and woodwinds. It never sounds messy and or loses composure no matter how busy the recordings get.

Secondly, you’ll notice how smooth the tonal transitions and progressions are as musical pieces unfold. There aren’t any “holes” or “bumps” in the delivery of lips movements, instrumental aggression, or room reflections. All the information is there with perfect phase alignment and a perceptibly weighted contrast. In order words, tonal perspective is presented effortlessly. Lyrics are more intelligible and wholesome while cymbal brushes are feathery, glare-free, and accompanied by a healthy scoop of gravitas. It’s easy to say it’s “smooth” but I’m more inclined to say it’s more “spectrally uninhibited.” Dynamic swings are also satisfyingly coated – giving a very tangible sense of weight, speed, and intention.

Lastly, the noise floor on the SR4 is extremely low – everything fades in from black – but in a nonartificial way. Low-level details are brought forth in a naturalistic, full, and contoured manner. From the delicacy of breathy intakes to the fibrous strokes of a bow across strings, it never sounds contrived. As far as bass response, it’s naturally taut and encompassed. It’s not presented in the “typical” insistent, “spotlight” manner but in a form of solidity, authority, and coherence. Music is also carried further into the room with realistic decay and refinement. This low noise floor affords not only the freedom of immersion but also helps materialize the performance in front of you. It’s quite remarkable.

The SR4 preserves the rhymic quality of the recording and does so with poise and tenacity. The only way to really describe it is – lifelike. There’s stability in how the music moves in and out, with just the right shift in pressure – from the lowest of grunts to the gradual decay of venue reflections. Many of these qualities have tradeoffs, but they don’t seem to exist with the SR4.

You could have it all – vividness, smoothness, authority, and proper timbre. This is what I meant by “impossible.”