Quiescent T100SPA energy amplifier

Quiescent T100SPA energy amplifier

In the world of energy supply, it has lengthy been recognised that decreasing noise is the important thing to raised sound high quality. After all electrical energy is the lifeblood of any piece of audio gear and its situation will inevitably have an effect on the sound. Likewise in streaming audio increasingly more producers are realising that noise is the limiting issue, it’s a core purpose why streamed audio doesn’t at all times sound nearly as good because it ought to. When it involves amplifiers nonetheless, the place energy regulation has been the principle technique of smoothing out the issues within the electrical juice, the realisation that the principle sources of noise should be addressed extra comprehensively appears to be much less nicely accepted in most quarters.

Quiescent realised that radio frequency interference (RFI), electromagnetic interference (EMI) and vibration are main elements within the sound high quality of an amplifier. These two pernicious sources of unhealthy sound are all over the place, ever-increasing and evidently not helped by circuits primarily based on outdated applied sciences which have been refined however not overhauled over time. Although different applied sciences can be found, the best-known exception is Class D, the place switching energy provides have taken over from the established linear different however switched mode energy provides (SMPS) have their very own issues. This kind of provide is present in nearly each family equipment right this moment as a result of it’s cheaper and extra environment friendly, but it surely additionally produces big quantities of noise that pollutes the mains that provides our techniques.


Quiescent is the butterfly that metamorphosed from VertexAQ, its MD Nigel Payne (interviewed in concern 196) determined to take the anti-noise tech that was developed underneath that model and construct it into way more critical and impressively housed elements. Quiescent makes a variety of units which can be designed to cut back noise and microphony in an audio system, these embody loudspeaker modules, balanced mains provides and a variety of cables. Many of those are up to date variations of the VertexAQ merchandise but because of fantastically machined casework look completely completely different. What’s model new to Quiescent is that this vary audio electronics, of which there are two energy amplifiers – one primarily a doubling of the opposite into monoblocks – and a streamer.

Quiescent T100SPA

The T100SPA is Quiescent’s stereo energy amplifier and it’s a considerable magnificence the place each conceivable technique of maintaining noise and mechanical vibration at bay has been employed. On the skin you may see that the heatsinks are customized made with cooling tubes working down both flank. Look inside these tubes and there’s a helical form reduce into the wall, that is finished to interrupt up vibration and differs in every of the 16 cooling tunnels. The high of the chassis isn’t aluminium, however a composite materials referred to as Trespa, they use this with the intention to keep away from making a Faraday cage which traps RFI produced inside the amplifier. This stands out as the purpose why elements with non-metal cupboards usually sound extra relaxed and pure than the standard alternate options.

Inside this 27kg lump, issues get extra attention-grabbing not least by the advantage of the truth that most components have their very own inner casings and the facility transformer has a cap on high of it that kinds an absorption matrix. This uneven plate is designed to do three issues: take up excessive frequency noise, disrupt the sector across the transformer and kill RF within the bolt that fixes it to the chassis. The instances elsewhere will not be steel however are lined with an absorption materials to cease interference getting in, they comprise Audio Note (UK) Kaisei capacitors for the facility provide, DC blocking units, stacked rectifier bridges with anti-vibration remedy and anti-reflection units to cut back HF noise. There is just one pair of MOSFETs for every channel, presumably this avoids the timing points round exactly matching with a number of units. They produce 130 Watts per channel into eight Ohms which fits as much as 200W when the impedance halves to 4 Ohms. Not an enormous variety of Watts for the cash however this determine isn’t an indicator of high quality, and that’s way more essential than amount as you may be conscious.

Quiescent T100SPA heatsink

Back panel connections are very top quality WBT varieties, particularly that model’s Nextgen Ag silver sequence the place steel is saved to a minimal. The speaker cable terminals are from the identical vary. There are two further connections on the T100SPA within the type of an RCA socket and a binding put up, each of that are supplied for grounding functions which is a Quiescent speciality, I believe that that is one other space that we are going to see enhance in reputation sooner or later.

As a mouse

It is instantly apparent that the T100SPA is a quiet amplifier from the second you press play, I used to be genuinely stunned by how a lot quieter it’s than fairly nicely all the opposite amplifiers I’ve utilized in latest instances. Modern solid-state amplifiers are all fairly good on this respect, none of them hiss or buzz, however this isn’t as essential because the noise ground beneath the music they reproduce. That’s the place all of the high quality element is hidden in lots of amplifiers. You don’t hear it as noise reasonably it’s perceived as coarseness, as a scarcity of nuance, primarily as a masks to the issues that make an amplifier sound clear. What you get with this amplifier is a clear but not scientific sound that lets a lot element by means of and presents it in a very pure and easy vogue.

The second factor that hits you is that there seems to be limitless headroom, which isn’t normally the case with a 130W amplifier except it’s driving 96dB/w/m loudspeakers, e.g., audio system that don’t want quite a lot of Watts. The Quiescent achieves this with Vivid Kaya S12s (87dB) which aren’t very large, thus not theoretically able to excessive sound strain ranges. In reality, it did it with all of the audio system I attempted together with Bowers & Wilkins 802 D3s with their difficult low frequency load. This, one suspects, is as a result of there may be so little noise being amplified together with the sign, it provides such a powerful sense of ease that the conventional cues about loudness, which is actually perceived distortion, are simply not there. This diploma of calmness may be very uncommon and normally solely achieved with big quantities of energy.


The Quiescent makes different amps sound hurried, anxious to get by means of the music to the following monitor, and this sense of propulsion will be thrilling and entertaining with sure forms of music, however it’s finally a colouration that will get in the way in which of transparency, decreasing it to this diploma is kind of a revelation. It opens the music up fantastically, revealing the depth and dimensionality of the voices and devices while permitting every to be totally expressed, the calmness of the electronics permits the vitality of the music to dominate proceedings. I additionally love the way in which it reveals layers in good recordings, there are excess of anticipated in lots of latest releases.

There are two switches on the again of the T100SPA, one selects between XLR and RCA inputs the opposite turns the LED within the energy swap on and off. I used to be inspired to strive the latter and was shocked that eliminating one tiny LED opened up the soundstage so dramatically and elevated the sense of ease. I assume you want a sign that the amplifier is on however by no means felt to show the LED again on.

Quiescent T100SPA

Timing can be a strongpoint; there are a selection of calm and relaxed amplifiers round that journey up on this vital entrance, extra energy usually appears to undermine nimbleness and this can be why the T100SPA has a modest output for its class. Whatever the explanation the groove was totally pleasant on so many tracks that it was straightforward to get carried away, this presumably as a result of there may be so little noise to blur the transitions between notes and since it has greater than sufficient energy to manage the loudspeakers in use. It additionally delivers an enormous quantity of element from acquainted recordings, stuff that had actually by no means surfaced earlier than, even on massive techniques, the shimmer of bells, the timbre of acoustic devices and voices and the ripples in low bass on favorite items.

Audio cake

Quiescent have gotten to the crux of what it takes to make a really revealing and even-handed amplifier within the T100SPA. Don’t have a look at its energy ranking and assume you want extra, hearken to its easy management of the loudspeaker, and surprise why you’d ever want extra. That the construct high quality can be premium grade is the icing on a really tasty audio cake, if I had the funds there could be an actual hazard of investing in an amplifier that might make so many others sound crude. As a reviewer it could be a catastrophe.

Technical specs

  • Type Solid state stereo energy amplifier
  • Analogue inputs One pair WBT nextgen Ag silver single ended (by way of RCA jacks), one pair WBT nextgen Ag silver balanced (by way of XLR jacks)
  • Analogue outputs One pair of WBT nextgen Ag silver speaker faucets (by way of 5-way binding posts)
  • Power output 130Wpc @ 8 Ohms, 200Wpc @ 4 Ohms
  • Bandwidth Not specified
  • Sensitivity 1.6V
  • Distortion 0.03% at 24W into 8ohm, enter 1kHz
  • Signal to Noise Ratio 120dB
  • Dimensions (H×W×D) 140 × 440 × 400mm
  • Weight 27kg
  • Price £20,000


Quiescent Ltd


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November 14, 2023 at 09:06PM

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