Paul Hynes SR4 – The World’s Best Audiophile Power Supply

Sound

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.

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.”

About The Author

Mr. Audio Bacon himself. An open-minded electrical engineer and software developer by trade. I have an obsession with the enjoyment of all things media - specifically in the realm of music and film. So much heart and soul (and money) go into the creation of this artistry. My aim is to find out which products get me closer to what the musicians and directors intended.

15 Comments

Richard on July 13, 2018 at 12:53 pm

In my experience, my SR7 is indeed the finest PSU I have thus far experienced. I have auditioned, owned and still own other supplies from Teddy Pardo, Paul Pang, Kenneth Lau, SBooster, HDPlex, Teradak, Uptone Audio (JS2, LPS-1, LPS-1.2), and SOtM (sPS-500) and they are all fairly decent with the LPS-1.2 being a standout among this group for components that don’t draw more than 1A, however, in my opinion, the mighty SR7 is without peer. Good call on this one, Jay!

It is a very good review. Nevertheless it suffers greatly from the absence of the biggest competitor, the Uptone Audio LPS1.2. There are reports that the SR4 and the LPS1.2 are nearly on par. I would suggest to compare both in a post sriptum to make this review complete. Thanks

Matt, I own both PSUs, and use the LPS-1.2 to power the ISO Regen and the SR4 to power to tx-USBultra. For powering the ISO Regen, SR4 and LPS-1.2 are more or less on par (the SR4 sounding a bit brighter). For powering the tx-USBultra, SR4 sounds slightly better than LPS-1.2, imo. Both are great PSUs, worth their price. While I could live with the stock PSU of ISO Regen, the stock PSU of the tx-USBultra sounds terrible and is worth being replaced.

Hi Jay: Alex from UpTone here. I think the world of Paul Hynes, I am happy to see that he is at last getting more production going of the terrific SR4, and I would not want to detract from your nice review of it.

That said, your readers are correct that the most contemporary comparison would be with our newer generation UltraCap LPS-1.2–now based on paralleled ultra-ultra-low-noise and ultra low output impedance LT3045 regulators, and now offering 5,7,9,12 volt user-selectable output setting.

I just saw your e-mail and we will get a unit down to you this coming week. We’ll likely swap it for one of the four(!) original LPS-1 units that you previously purchased from us.

Actually, both the UltraCap LPS-1 and LPS-1.2 completely block the path of normal low-impedance AC mains leakage. Always have. But we later discovered (and yes Amir measured) that because the original Mean Well SMPS we were supplying with the LPS-1 did not connect AC ground to DC -ve output (“ground”), some high-impedance leakage could get through (because of a few dozen pF total capacitance of the transistors we use to alternate ultracapacitor banks instead of noisy mechanical relays). We discussed all this and published measurements about it here:https://www.computeraudiophile.com/forums/topic/37034-smps-and-grounding/?do=findComment&comment=734822

The solution is extremely simple: Just ground-shunt the “energizing”/charging supply to prevent high-impedance leakage from ever entering our DC>DC UltraCap unit. Many have done this as an easy DIY. And the LT3045-based LPS-1.2 comes with a new UpTone-branded 36W SMPS which is designed with an internal ground-shunt. So no AC leakage of any kind comes from the output. We also offer this new charger separately for $15 for those original LPS-1 owners who would like to address this minor issue but don’t want to run an external ground wire:https://uptoneaudio.com/products/uptone-branded-7-5v-4-8a-36w-smps-with-internal-ground-shunt

My sincere apologies to Paul Hynes for this off-topic post. But I feel it is important to correct mis-information. Thanks, Alex at UpTone Audio LLC

I prefer copper. If you prioritize transparency and detail – go silver. Paul Hyne’s silver is probably the smoothest I’ve ever heard. If you listen to mostly vocals or music that benefits from a more warm, golden sound – go Zenwave 7N copper.

The SOtM is far more revealing. But the TLS is warmer and is more tonally satisfying. I typically would opt for the warmer sound but the SOtM is able to unravel so much of the music, especially in regards to transient reproduction – it’s hard to pass up. For lack of a better word, the SOtM (with clock, evo caps, and 7N upgrade) just sounds more real.