WESTMINSTERLAB Quest + Rei Extended Carbon Pack
Power amplifiers
Hong Kong's WestminsterLab is a one-man project. Angus Leung collaborated on the development of cables with Lumin, which know-how he used under his own brand and added amplifiers to his portfolio, namely the Quest preamplifier, Rei monoblocks, and Monologue phono preamplifier. It's nice to see the younger generation of designers trying to do things differently from those who once blazed the trail of high end audio, like Nelson Pass, Ed Meitner, or Dan D'Agostino. With the brands rooted in the 80’s and 90’s one expects something and he gets it, there are no surprises. With small workshops like WestminsterLab, you never know what they'll come up with. The result can be sexless and end up in audio oblivion, or it can be successful and then the star rises. WestminsterLab is one of the latter. The Quest preamp and Rei monoblocks are made to be a combo, and while they will stand on their own, there's not much point in splitting them apart. But they are not completely equal partners, I would say that the Quest (70%) contributes the most to the final sound, while the Rei (30%) makes up the rest.
Function and form
The look of both the devices is minimalistic and neat. Upon switching on, the small logo lits up. Nothing else happens, there is no hum or noise to tell you that the amps are on. Although they exist in standard versions, the reviewed pair was improved by carbon shielding inserts inside and carbon panels that are said to elevate the performance.
WestminsterLab Quest
The 13kg heavy (or should I say light?) preamplifier is a dual mono full balanced design to isolate left and right channel, minimize interference between the channels and improve L-R better separation. Instead of a potentiometer, the attenuation uses stepped resistor network and low noise relays, that provide 64 steps of listening volume. The volume adjustment is accompanied by a silent click of the relay and the current value is displayed. The “display” of the device is a smart and nice feature: 11x21 holes milled in the aluminium fascia equipped by white LED diodes. Easily legible from distance, minimally interfering with the preamp’s circuits. Although WestminsterLab does not provide details about how it works, the Quest provides a toggle switch (located at the bottom panel) that allows to select one of the two “grounding modes”. Each mode sounds different, the default mode (with the toggle on the right side) was much better balanced to my ears. Power management uses 10 separate power rails, a dedicated transformer and a PSU for control circuits, and linear regulators. The Quest is a very quiet preamplifer as a result, providing 120dB of dynamic headroom according to specifications.
The preamp only provided an array of 3x2 gold-plated XLR inputs and 2x2 XLR outputs, but it is prepared to accept extension modules that plug into the bays in the rear. The chassis of the preamplifier is said to be resonance-tuned after extensive listening tests and sits on three hemispheric and polished brass feet.
Bass management
WestminsterLab Rei
The design approach of the 16kg Rei monoblock is similar to the Quest, that is to minimize resonances and electronics crosstalk. Angus Leung adopted the iBIAS technique (marketed by Krell in 2014) that allows for adjusting the amp bias in real time depending in the load and input voltage. This way the amp mimics Class A but only when it is needed. The result is that there is a lot less heat generated, so the chassis can be smaller and power higher. For its size, each Rei is a powerhouse, capable of delivering 100, 200, and 400W into 8, 4, and 2 ohms. It can also be bridged to double on these values. Four Reis can be easily employed in bi-amping scheme as the Quest provides two pairs of XLR outputs. It is important to know that the Rei only has an XLR input, no RCA. It is said that there are only 12 parts in the path of the signal from the input to the output of the Rei. I wonder whether in a pure RCA version not even fewer parts were needed.
Interestingly, the cooling scheme is asymmetrical as WestminsterLab’s designer sees the heatsinks as necessary evil. I understand what he means – unless the fins are properly designed, they tend to ring, and they add/subtract these resonances to audio signal. Considering how much Angus Leung talks about resonances, it surprises me how much the chasses of the Quest and the Rei are alive.
Clarity & delicacy
I guess you’d agree that the best audio component is an acoustically inert component. At least the common logic says so. Unwanted resonances of anything (cabinets, chasses, cables, transformers, sockets) are the enemy because they find their way into the sound. That is, unless the manufacturer uses them as wanted resonances, a sort of acoustic exciters, as Harbeth does in the loudspeakers, for example. Still - it's only been a few months since I complained about top lid resonances of the Aries Cerat Kassandra DAC. WestminsterLab devices outperform Aries Cerat easily in this respect.
Tapping a WestminsterLab chassis - and it doesn't matter if it's the Quest or the Rei - is like tapping an empty steel mailbox or a vintage Technics from the 80s. I was expecting a muffled inertness from the carbon panels, so I am surprised at how much they rattle. But as you can see from the opening description, Angus Leung is an audio-tuner and I'm guessing he tried other options before settling on this rattling one. I'm an audio-tuner too, so I tried to silence the top plate and put 6 kilos of lead atop it. The sound got worse. I replaced the lead with 750 grams of stainless steel. The sound got worse.
What about putting something underneath the Rei? With three Stillpoints Ultra 6 V2 underneath each power amp, the WestminsterLabs have undergone perhaps the biggest transformation I've ever experienced with these feet. If you own a Quest or Rei or both, be sure to give it a try. If the results are equally positive, I guarantee you won't want to take them out again.
Tonal accuracy
The Quest + Rei combination is pleasure to listen to. The compact size boxes set some expectations, connected to how Class D amps sound. I expected transparent power and authority, with clean but colourless midrange, and pristine but rather uninvolving top end. I was very wrong.
The WestminsterLab combo is tuned like a musical instrument – it sounds dynamic, smooth, nuanced, lively and musical. In the midrange it can challenge any Class A amplifier out there. It radiates warmth and presence, without sounding warm. It is rich and colourful, without becoming too ripe. It has superb detail and clarity, without sounding etched. All acoustic instruments and voices throw illusion of three-dimensional palpability, a be-there presence in the room. Alike the best Class A amps, the top end of the Quest + Rei combo is open and shimmering, yet a bit subdued. Unlike Class D amps, it handles harmonics with aplomb, so pianos or cymbals sound live and true, with just a touch of silky sheen that makes the combo a bit more forgiving and closer to a vinyl playback experience. The amps are exquisitely transparent and their noise threshold is low (>100dB of S/N ratio guaranteed), so ambient clues are easily audible, although in a bit more dimmed fashion than I am used to, as if the WestminsterLab blackness was a bit viscous. This is the part than can be further voiced with how the amps are supported (platforms and feet) and connected (signal and power cables), for they are pretty sensitive to both. The aforementioned Stillpoints Ultra 6 V2 are the proof of it. With them, the bass gains on authority and impulse transient delivery, the bass guitar goes from deep rumble to penetrating growl, with string attacks clearly defined.
Spatial resolution
Some reviews mention that the Quest and the Rei cannot do without each other. Not entirely. It is true that it makes a lot of sense to use them as a combo. Yet, if you decide to only use a pair of the Rei, it should not be an issue to find a different preamp or feed them directly form the variable output of a source component. We have tested such a set-up against Audia Flight Strumento No.8 monos without a preamplifier and the result was not bad at all. However, the Quest adds an extra layer of authority and resolution, and not only does the Rei profit from it, Audia Flight´s performance got improved too. Potentially, the Quest may be an excellent preamplifier option for any audio set-up in a broader sense.
At this price point or less, there will be many alternatives to the Quest and the Rei combo too, but not in such a compact format. There the WestminsterLab rules. I personally think the devices like it are the future of high-end audio. Until now, this domain has been reserved for Class D amps, with all their pros and cons. The Quest and the Rei are a very successful take on removing the cons and keeping the pros. I am impressed with how they sound, less impressed by their price…
WestminsterLab Quest: 27,000€ / WestminsterLab Rei: 36,000€
Recommended resellers
DiokAudio.cz - Hifi Studio Pánský Dvůr, Ostrava, +420 608 943 409
Manufacturer's website: https://www.westminsterlab.com
Associated components
- Sources: Ayon CD-35 HF Edition
- Amplifiers: Audia Flight Strumento No.8
- Interconnects and speaker cables: Stealth Audio Metacarbon, Synergistic Research SRX
- Loudspeakers: Silent Laboratories Equilibrium
- Power conditioning: GMG Power X-Blocker Exclusive, TweakGuru Horizonta
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