Paul Hynes SR4T

Price: $675

Product link: Discontinued.

Update 9/11/2023: Paul Hynes has gone under a lot of scrutiny for misappropriating funds and customer deposits. Many have lost their deposits, including myself. There’s recent speculation and some confirmed accounts of Paul stealing deposits from unsuspecting customers for potential power supply builds. I’m just keeping this here for posterity, but please do not attempt to purchase a power supply from Paul Hynes.


Unfortunately, PHD Ltd is now closed because of insolvency. I figured I’ll keep their power supplies in this comparison if you’re looking for it in the used market – or if you’re simply curious like I am.

The “T” designation has been nicknamed Turbo as it provides a performance boost over the standard SR4.

Build & Specification

  • The SR4 configuration uses two rectified and smoothed supply rails prior to the regulator circuitry, one for the output stage and one for the error amplifier and output stage driver stage. Both of these pre-regulator rails are configured in balanced rectification mode.
  • The SR4T adds an additional low power voltage regulator powering the error amplifier/output stage driver resulting in better overall regulation, better transient response/settling time and lower dynamic and static noise.
  • The SR4T is not the same as the DR configuration used in Paul’s SR5 and SR7 custom-build designs, as the DR configuration uses two high power voltage regulators in series. However, the SR4T version moves the performance closer to the performance of the standard SR5 and SR7 PHD Ltd products.
  • The SR4T has the same power rating as the standard SR4 and is also in the same chassis. For those looking for higher performance without a large cost penalty the SR4T is an excellent solution for power ratings up to 2.5A continuous (SR4T-12) or 2A continuous (SR4T-19).

The Sound

I was actually pretty surprised at how different the SR4T sounded in comparison to the original SR4. First, for such a small package, the SR4T has a similar ability to realistically 3D mold the music like the Sean Jacobs DC4 and SR7. But it’s not as expressive or faithful. But still impressive for the price. For what it’s worth, these are the only three power supplies that have a convincing corporeal body – and they all have a very similar neutral tone.

The SR4T has good intent, decent texture, and air. Treble is tuneful and has adequate shine. The midrange has plenty of clarity and resolution. It’s dense, but a little glossy. Bass has decent volume and momentum but is more even even-keeled than forceful. Where it shines is in representing textural cues and opening up the soundstage. Imaging is spot on and everything flows with variability in density.

Overall, each part of a recording has body and weight. Even the tiniest of details. It’s pure analog, no gaps, no grain. It’s a heavier grey sound rather than a stringy one. In other words, it’s more heavy-handed and tangible but still embraces a good level of detail and nuances.


I’m not a huge fan of the tone. It’s a greyish neutral. But everything does sound truer to life in an analog way. However, it’s more condensed than it is open sounding. It also doesn’t have authoritative, wham-bam lower octaves or highly energetic top end.

Who Should Buy the Paul Hynes SR4T?

I think you’ll have to be a huge fan of a dense and neutral tone. You’ll get a taste of what the higher-end power supplies can do at the cost of color. Otherwise, the SR4T embraces vocal realism, is dynamically expressive, and connects music with lifelike timing. It has a high-end sound without the exorbitant price.



  • Top-tier corporeality

  • Lifelike timing

  • Midrange detail and clarity

  • Fantastic pacing and presence

  • Tone is very neutral, not a soulful brown

  • Not the punchiest sound

  • Brilliance is a little subdued


vs. Uptone Audio JS-2

  • JS-2 has more brilliant shine
  • JS-2 has better tonality
  • SR4Tis chunkier and meatier
  • SR4T has more analog realism

vs. Paul Hynes SR4-12

  • Has more shine and vibrance over the SR4-12.
  • The SR4T is more colorless in comparison.
  • SR4T has far better bass and sub-bass
  • SR4T is smoother.
  • SR4T is quieter, more focused, and more articulate.
  • SR4t has more variance in density.
  • SR4T is more dynamic and crunchy
  • The SR4T does everything better aside from tone.
  • The SR4-12 just has more essence and soul.

vs. Sean Jacobs DC4

  • The SR4T actually reminds of the DC4 in some ways. They both have a similar tone and approach to shaping out the music. The DC4 does this at another level, but gradients and curves gives the impression of “They’re there.”

vs. JCAT Initio 3

  • SR4T has more shape.
  • Initio 3 has a much darker tone

vs. Plixir Elite BDC

  • The SR4T is more forward, denser, and more molded. The music has more weight.
  • The SR4T has a chill more shaped sound.
  • The Elite BDC has a lot more edge and shine.
  • The Elite BDC has much better outlining.
  • The SR4T is neutrally toned in comparison.
  • Elite BDC isn’t as meaty, especially in the midrange.

vs. HDPLex 300W

  • The HDPlex has much better tone (more golden).
  • The SR4T has more shape and tangibility.
  • The HDPlex is more “musical” but is dimensionally flatter.
  • The SR4T has realistic molding and is smoother.

vs. Paul Hynes SR7

  • The SR7 is better in every way. Although they’re both neutral, the SR7 is still more organic sounding.