Puritan PSM 156: cleansing and purifying your mains electrical supplies

30th July 2017

Looking to clean up a gamut of noise around his hi-fi via mains conditioning, Paul Rigby reviews Puritan’s new flagship product, the PSM 156

Oxfordshire-based Puritan design and manufacture products that cleanse and purify mains electrical supplies. The company likes to emphasise that it purifies while keeping the power and also the dynamics present in the supply. It tends to develop products that purify the electrical supply in stages rather than in one fell swoop. Hence, Puritan likes to boast that its AC waveforms are clean but, “…also allows the hi-fi chain to maintain its sound quality.”

The last flagship product from Puritan, the PSM 136, arrived with six 8 Amp outputs. This unit wasn’t helped by protection from the 13 Amp plug so the company, at that time, decided to fuse each and every output. This is a consumer box, after all and you’re bound to get someone looking to plug in a living room heater or some such. Not recommended but it has, according to the company, happened.  Tests showed that, in sonic terms, this individual fusing didn’t detract in sonic terms. Many of Puritan’s users begged to disagree, though. Ever the listening company, Puritan decided to act.


What it has done is to produce a new unit that features the same degree of filtration and cleansing but offer six outputs that can handle 15 Amps. This means that they do not require individual fusing and depend on the mains plug instead. The new unit, which sits in the Studio Master range, is the PSM 156.

Designer and Puritan boss, Mike Lester commented, “So the PSM156 aim was to eliminate the need for overcurrent protection in the box with the fuse in the plug of the power lead providing the overall safety (Schuko, Nema, etc. versions have a single internal 15A fuse as these plugs are unfused, this fuse is not present in UK versions). To achieve this each independently filtered output needed to be rated at 15A. This is achieved with chunkier heavier windings. As increasing the current potential with heavier wire and less windings reduces the attenuation of unwanted frequencies this is compensated by increasing the number of stages to provide superior removal of unwanted frequencies with unfettered current delivery.  This route of  increasing the number of multiple cumulative stages of purification from 39 in the PSM136 to 52 in the PSM156 has given further gains in  performance.”

While testing the unit, I also grabbed a batch of Puritan’s mains cables to hook up to my system.


I began with my CD transport and DAC on the premise that there’s a whole heap of noise floating around this area. I initially hooked both the transport and DAC to basic mains cables. The type you’d find attached to a kitchen kettle and then to a basic power block, the basic white plastic type bought at a hardware store. Apart from the mains, I placed each on quality hi-fi supports from Atacama and further – rather expensive – isolation products from HRS. Hence, the in terms of potential sound quality issues, the mains connections were the principle variable here.


As I was getting ready to test the Puritan, I listened to my hi-fi connected to a basic, High St power block as a form of base level reference. A truly horrible item that actually adds noise to the system. There is no effort to remove any noise here, it’s job is to put the kettle on, nothing more than that. After listening to the dross it was spouting, I prepared the Puritan by plugging it into an adjoining wall socket. No components of my hi-fi were attached to it, at this point. The Puritan was connected to the wall socket ’empty’, as it where. I was playing Depeche Mode’s Enjoy The Silence at the time through the High St socket.

Once the Puritan was ‘in the wall’, as it where, I stopped and paused. I couldn’t quite believe what I was hearing and stopped in my tracks when the music played again. There was a distinct difference in sound quality. It seemed that the Puritan’s mere presence within the mains was having an effect because it started to clean up the mains, adding a slice of focus and reducing noise right there and then. I fact, I could hear a low level bass rhythm for the first time. OK, it took a bit of searching out with the ears. It wasn’t absolutely obvious but it was there. This entire happenstance was just that, a pure accident on my terms. I wasn’t expecting it (although I know of expensive Vertex AQ kit designed to do just that, it will have an effect by merely being part of the local mains system). For the Puritan to have such a positive – and wholly unadvertised effect I might add – effect was startling, though. It also means that, if you run out of sockets, any other kit plugged into the local mains circuits will benefit from a measure of cleansing even if not directly attached to the Puritan.


A good, if rather unexpected, start then! I then plugged my CD transport into the Puritan along with a set of Tellurium Q cabling and my Nordost mains block and found an immediate drop in offensive noise frequencies. The result was a far smoother midrange which affected all areas of the sound spectrum. Vocals offered an expressive element, adding a texture to the voice while electric guitar string plucking no longer suffered from an offensive, bright upper midrange. Drums, meanwhile, provided a greater rhythmic capacity. They rolled with ease as the beat flowed instead of stumbled. Imagine walking over cut glass and then (after a spell in A&E) doing the same on a plush carpet. That imagined difference was how the drums sounded to me as a ‘before’ and ‘after’. The harshness in some elements of the soundstage remained but the sonics were much improved.

I then plugged in the DAC using the same superior cabling and the noise reduced so much that the gain had to be raised two notches on my pre-amp to achieve the same level. Doing so increased the general level of detail resident in the soundstage. This meant that the vocal harmonies offered greater information, becoming a collection of voices instead of an amorphous blob. Bass was stronger and offered a effective mass while the lower lying synth runs, rather hidden in the mix thus far, made a more significant appearance, as did the ride cymbal.

I then plugged my vinyl chain (phono and pre-amps) into the reference Nordost power block with Tellurium Q power cable and played David Gray’s Please Forgive Me.

All kinds of changes occurred when the Puritan entered the frame, the drums emerged from a silent background giving the complex rhythmic drumming a distinct and penetrating effect with oodles of character and oragnic resonance.

Speaking of which, Gray’s voice, such a grainy instrument on its own, benefitted with a reduction of noise, giving his delivery more air and space to manoeuvre. The grains in his voice were almost seperated. You could hear into his voice. That is, the tiny intonations as he sang each word held more information and clarity.

There was also more air and space between the synth and piano, allowing each more elbow room to provide a greater tonal accuracy as the smoother midrange performance provided more ease and flow.

PSM156 Rear

I then attached the supplied power cables to the phono amplifier and pre-amplifier and back to the Puritan. The result was a further reduction in noise and a richer, more mature sound. Sonic strident spots were calmed, clarity was infused into the soundstage while further noise reductions allowed the subtle aspects of the music to be brought forth. Once the gamut of tiny details were visible to the ear, the song itself provided a fuller and busier experience.


I was impressed by two things from the Puritan. The decrease in the amount of noise allowed me to hear more information, enhancing all frequencies over the soundstage. The improvement in clarity and focus also helped the music to flow and eradicated harmful frequencies that sometimes demanded hands over the ears. More than that, though, while noise was reduced, the dynamics were never reduced. Hence, the music retained its life and vigour. I never thought that the ‘treated’ music ever sounded dull which is a great tribute to the design. The Puritan PSM156 is an ideal method to treat mains noise and distortive elements, letting you hear more music which is, after all, the point of hi-fi.



PSM156 is £1,450 (including the Dual Dissipative connecting lead from the unit to the wall)

1.0m mains lead is £75, 1.5m is £85, 2.0m is £100, 4.0m is £130. Other lengths on request.

Tel: 01491 680444

Web: www.puritanaudiolabs.com

GOOD: low noise, dynamic sonics,

BAD: nothing at the price




Origin Live Sovereign turntable
Origin Live Enterprise 12” arm
Transfiguration Proteus cartridge
Leema Essentials CD player
Benchmark DAC2 HGC
Icon Audio PS3 phonostage
Aesthetix Calypso pre-amp
Icon Audio MB845 Mk.II momoblock power amplifiers
Quad ESL-57 speakers [One Thing modded]
Vertex AQ cabling
Tellurium Q Black speaker cables
Harmonic Resolution Systems Noise Reduction Components
All vinyl was cleaned using an Audio Desk’s Ultrasonic Pro Vinyl Cleaner
Nordost Quantum QBase QB6 power block