There's Nothing Else Like It
Quiescent's extraordinary combination of electronic and structural design, materials, electronic noise reduction and acoustic noise reduction puts it in a league of one.
About The T100SPA
Quiescent take a very different approach to the relative priorities of an amplifier design. If you look inside the case you will see a complex array of individual stacked modules. These are elements of the amplifier that Quiescent deem should be constructed as individual sub-assemblies so that they can be separated out for the purposes of RFI and microphony reduction. One module for example contains substantial mains filtering (including DC blocking) while other modules contain anti-RFI and anti-vibration techniques for things like the input stages and output stages. Yet more modules contain other discrete elements – all in the pursuit of that anti-RFI and microphony strategy.
And when it comes to the electronics, Quiescent go down the quality/simplicity path. Indeed they say that their intensive noise reduction strategy brings the sound quality of simple designs to the fore. The output stage is a single pair of MOSFET devices per channel running in class A/B, with current feedback, that delivers a sensible 130W into 8 Ohms.
And when it comes to performance, the first thing you notice with these amplifiers is that they are quiet and transparent – you'd sort of expect that. But when things get going, it's the timing, texture and structure that comes to the fore. Indeed the way the architectural structure of music is revealed, with seemingly limitless headroom, belies the relatively modest published figures. In fact we all secretly know that for most normal listening we don't need much more than 5-10 Watts, ever. Maybe it really is all those RFI and vibration demons that are robbing an amplifier's true performance.
Of course, we have only skimmed the surface of what these amplifiers are about here. Check out the Quiescent site and also this review by Jason Kennedy for a lot more detail. And give us a call to discuss a demonstration – these are important amplifiers to hear.
Tech Insight
A striking feature of these amplifiers, and a testament to the whole vibration reduction philosophy, is the heatsink design. Bespoke to Quiescent, these heatsinks are not cut from a long extrusion, not covered with resonant fins, and don't have any parallel sides. These items are machined from solid billet, have curves and distinctive circular vent tubes with an internal helix cut to further breakup the surface continuity. And the bottom surface is chamfered so that it is not parallel to the top.
The output transistors are of course bonded to the heatsinks (two heatsinks on the stereo amp, one on the mono), for cooling purposes. But these heatsinks are also a fundamental component in minimising microphonic pollution in those output transistors. Quiescent say that the self generated microphony in power transistors, as they swing output current in response to the musical signal input, can be considerable, and if left untreated will smear the output significantly.
Specifications
Audio Outputs
Minimum load impedance, 2Ω.
Power output (rms), 130W per channel into 8Ω, 200W per channel into 4Ω.
Gain, 26.5dB.
Frequency Response, -3dB at 0.5Hz to 600KHz.
Slew Rate, 91V/us.
THD @24W output into 8Ω load, (1KHz sinusoidal signal), 0.03%.
S/N ratio, 120dB.
Terminals, WBT nextgen™ Ag Silver conductor binding posts.
Audio Inputs
Impedance, 10KΩ.
Sensitivity, 1.6V.
Sockets, 2 x WBT nextgen™ Ag Silver conductor phono and 2 x silver conductor XLR (switchable).
Grounding
Chassis, M5 Binding post on rear panel.
Signal, RCA socket on rear panel.
Casework
Finish, bead blasted natural or black anodised high grade aluminium with high-impedance non-metallic top.
Cooling, passive custom-built heatsinks.
Dimensions (HxWxD), 140 x 440 x 400mm.
Weight, 27Kg.
Power Input, 230V, 50Hz.
Matching & Setup
These amplifiers are fairly load tolerant and will quite happily drive 4 Ohm speakers with medium/slightly low efficiency (say down to around 86dB). They will go down to 2 Ohms but are probably not the best match for power hungry ribbons. Pair them with something a little more sensitive however and we find that the textural responsiveness of the combination brings an exceptional level of realism.
With setup, take every care with positioning and proper supports. The same goes with cabling. And of course, the Quiescent couplers, cables and mains conditioners make a natural and truly synergistic combination. Whichever way you approach Quiescent as a brand, as a way of system building, these amplifiers take that whole strategy up to a truly remarkable level.