Quiescent T500VA

REVIEW
Paul Soor
Sep 25, 2025

I’m getting emotional as I listen to David Sylvian’s ‘Praise (Pratah Smarami)’ from the album Dead Bess On A Cake [Virgin]. I don’t know why. All I know is that I’m listening to the Quiescent T500VA Balanced Mains Supply with Peak power cables. I’m grateful that talented people in companies like Quiescent understand the electrical noise present in our modern world. It corrupts the delicate signals required to reproduce music, making me feel the way I do.

This was my first experience with a balanced power supply. I was fascinated by the Quiescent T500VA, with its inherent anti-noise properties and other innovations discussed later. I recently replaced the electrical mains power supply to my HiFi (see issue 237). The results have been fantastic, and the Quiescent T500VA was connected to that supply. Another reason I was fascinated is that I use a complete loom of Nordost Odin mains cables via a QB8 MkII mains block. It’s a high-end reference, which the T500VA would replace.

Easy set-up

The beautifully designed, engineered, and manufactured Quiescent T500VA can be positioned horizontally or, in my case, vertically, like an old tower PC. Power input was provided by the wall socket using a Nordost Valhalla 1 cable. From the TV500VA, there are two types of power output: four balanced, primarily for low-power, sensitive electronics, and two direct, for high-power components. I used the balanced outputs to my dCS Rossini Apex DAC Player, dCS Rossini world clock, and my David Berning preamplifier. I tried the direct connections to each of my David Berning QZ Mono power amplifiers.

The output connections from the TV500VA use the Neutrik powerCON insert-twist-lock-click connectors. Therefore, Quiescent supplied their Peak mains cables (tested in Issue 205) from the T500VA to connect to my components. I found the Peak mains cables interesting because they include 10% silver-filled oxygen-free copper, Teflon, and air dielectric. These are similar to the ingredients in the wires I usually use, albeit in a completely different configuration. A higher level of mains cable is also available in the form of the Apex, which is 100% silver.

Quiescent also sent me Apex Couplers (reviewed in issue 197), which work brilliantly under the Quiescent T500VA to address electrical vibrations further.

Addressing the Vibes

There’s a helpful analogy; for once, it involves no cars, watches, or cameras. Instead, think of a flat pond. Throw in a pebble and watch the waves radiate out. When the waves hit the pond’s edge, new waves reflect and interfere with the original. Damping/absorbing those reflected waves is the goal. However, they need to be “critically” damped – not too much or too little – so the original waves suffer no interference at any time.

In a call with Nigel Payne, he explained how the Quiescent T500VA is the culmination of lessons learnt from his involvement with Vertex and the formation of his company, Quiescent. Specifically, the focus remains on addressing vibrations caused by electricity when it is excited and energised. This causes high-frequency electrical fields, which result in radiofrequency and electromagnetic interference. Notably, Nigel couples this with the recognition that capacitors do not behave linearly as simple reservoirs at high frequencies, where they cease to conduct. The result is electrical standing waves/resonances, which, as he has observed, interfere with the original audio signal —the waves that reflect.

So, where does all this high-frequency noise come from? These days, one significant source is something that in modern civilisation we cannot live without – switch-mode power supplies (SMPS) that convert high-voltage AC into low-voltage DC. SMPSs can switch at frequencies ranging from a few kHz to a few MHz, so our hi-fi systems certainly pick them up. There are large industrial versions (multi-car battery chargers) to tiny SMPS in things like LED lights. However, not all SMPSs are evil! Some brilliant implementations exist in hi-fi, but others don’t care about our needs. Quiescent cares!

First Listen

My first listening session could have been better. The musical magic had gone. It was lifeless and dull, and piano notes lost their sparkle and bell-like quality. The music felt slow. I wasn’t that interested in listening. The Engineer in me said I must’ve done something wrong, and it will be something fundamental. A call with Nigel revealed that sometimes, there can be a mismatch between a balanced power supply and valve-based amplifiers.

I connected the power directly to my David Berning Pre One valve preamplifier. The pre-amp has the option of a 230V AC direct input (that the Quiescent T500VA was feeding) or 12V DC (bypassing the internal power converter). I have a Linear Tube Audio (LTA) linear power supply that converts externally to provide 12V DC. Nigel suggested using the LTA powered by the T500VA. Bingo! The musical magic came back and more. The lesson here is that if you try the T500VA at home and don’t hear an improvement, take advice from your dealer.

Listening, joy

We all know the feeling: You make a good change to the hi-fi. You know that because you rediscover old favourite music with a wonderful new perspective, and you’re blown away. The new musical experience takes your breath away. This is the Quiescent T500VA effect.

“Oh, wow!” That was my reaction listening to ‘I Dream of Spring’ and ‘Coming Home’ by k.d. lang from the album Watershed [Nonesuch]. Her pristine, expressive vocals combined with musical arrangements that include drum machine samples and banjos in a way that should not work. However, it does because the T500VA’s ability to integrate music at interfaces cleanly and naturally adds to the musical flow.

I also noticed an improvement in low-level, low-frequency articulation, such as sounds like gentle, soft pitter-patters from percussive instruments. I could feel the texture of those instruments, combined with the slow push of air. This added to the physical presence of the music.

‘Drowned World/Substitute For Love’ by Madonna from the album Ray of Light [Maverick/Warner Bros] has been a family favourite since its release in 1998. The T500VA gave me a new and welcome, wonderfully intimate, close, and involving experience, further underlining my belief that this is Madonna’s best album ever.

Low-frequency information

The Quiescent T500VA’s ability to articulate low-frequency information is mesmeric. When listening to ‘Kid A’ by Radiohead from the album Kid A [Capitol Records], the decay on lower notes felt longer, with a richer texture and more tonal colour. Like the title track ‘Did You Know That There’s A Tunnel Under Ocean Blvd’ by Lana Del Rey [Polydor], there is a greater sense of acoustic space on an already wonderfully spatial track.

The soundstage is different. It doesn’t seem to impress by not impressing. There’s a sense of proportion which feels even more creative. I wonder if that was the high-frequency intermodulation distortion?

Something occurred to me during my listening sessions – they were all brilliant! Whether real or perceived, there are some days and hours when the system sounds much better. For me, it is Saturday afternoons or Sunday mornings. Who knows why? Is it geography, the architecture of the local power supplies, how they are connected, plus a hundred other things? I’d say yes to all. The point of the T500VA is to eliminate electrical noise in and around the hi-fi. The fact that every day is now an excellent listening day suggests the Quiescent is doing a fantastic job dealing with external electrical noise that is usually out of our control.

Value for money?

On the face of it, the T500VA is a significant investment. Add five Peak power cables, and you’re looking at around £22,000. However, if you consider upgrading to the most high-end power cables, that would only get you one, not the five I need. Factoring that your system could, as in my case, sound its best much more of the time, the T500VA and Peak power cables now look like an excellent value for money. Suppose you are considering upgrading to high-end power cables because you appreciate the significant difference they can make. You must also factor in a home demo of the T500VA balanced mains power supply. The ultimate recommendation is to ask myself if I could live happily ever after with a T500VA in my system? You bet.

Technical specifications

Type: Balanced mains supply
Input: C16 socket, 230-240V AC, 50-60Hz
Max Power Load: 2,200W
Power output: Balanced -115-0-115V AC up to -120-0-120V AC, 50-60Hz Neutrik PowerCON (total max load 750W) utilising common mode noise rejection (sockets 1-4), Direct 230-240V AC, 50-60Hz Neutrik PowerCON with total max. load 1,500W (sockets 5,6).
Output sockets: Quiescent proprietary mechanical and EMI/RFI absorption and grounding. Inline mechanical and EMI/RFI isolation module. Independent Balanced and Direct isolated rear panel sub-plates for maximum mechanical separation of sensitive source components from high-power electronics.
Isolation technology: Custom-wound fully balanced toroid transformer directly coupled to patented QPower™ module. In and out high-speed shunt filter and inline EMI/RFI absorption.
Finish: Bead blasted natural or black anodised high-grade aluminium and non-metallic top.
Dimensions (HxWxD): 14x44x43cm
Weight: 28kg
Price: £16,300