WestminsterLab Quest preamp and Rei mono power amps

Review Context
The Quest and Rei were listened to in the main system that normally consists of the CH Precision C1.2 DAC, CH Precision L1 preamplifier, CH Precision A1.5 power amp, and Magico S1 MkII speakers. Digital sources include the Antipodes K50 and Grimm MU1 music servers, and the Aqua Diva M2 CD transport. All interlinks are Driade Flow Link Reference 808, balanced and unbalanced, and the speaker cables are Driade Flow Reference 808.
The CH components are placed on Artesania Exoteryc and Aire racks with Carbon Fiber Linear Arms, and the digital sources are placed on HRS EXR Audio Stands. The WestminsterLabs components were listened to on both racks, as well as on an Artesania Organic Line Modular Floor Platform.
In addition to the usual Magico S1 loudspeakers, I also used the Apogee Centaur, Apogee Duetta Signature, and Driade Premium Model 9.
All components, including the review components, are powered by the PS Audio P20 PowerPlant.
Listening – Rei power amplifiers
Rather than listening to the two WestminsterLab components as a system, I wanted to assess precisely how the two WestminsterLab components differed from the CH Precision components. To that end, I set up the Quest preamplifier and Rei power amplifiers in parallel and started with the power amplifiers positioned on an Artesania Modular Floor Platform. This platform has a different effect on the sound than the Artesania Aire platform used for the CH power amp, but I figured the differences between the amplifiers would likely outweigh this.
Maybe it’s the iBias and CCS systems, which are said to allow for a faster warm-up time than typical Class A amplifiers, but, holy guacamole, even when started cold, the Rei’s impressed me right away. This was Love at first listen. As the amplifiers warmed up, they did not change much at all. All I heard was a slight increase in fluidity and refinement and the evaporation of a slight initial dryness, but otherwise, I feel they perform simply sublimely even when cold. In this regard, they behave very similarly to the CH amplifier. Speaking of which, even after playing for hours on end, thanks to their adaptive iBias system, the Class-A Rei’s don’t get any warmer than the Class-AB CH A1.5.
The Rei’s are characterless in the best sense of the expression. They are so beautifully clean and utterly neutral that they are hard to describe. Where should I start? Well, let’s address the central question first, shall we? How do the Rei’s compare to the CH A1.5?
Well, I must confess being worried for a minute, as the differences between the two are far more minor than anticipated! It took me a couple of cable swaps before I could reliably identify them. Basically, in this first comparison, the two were predominantly comparable, the only exceptions being that the CH A1.5 is a little airier and more refined, as well as a little sweeter, and the WestminsterLab Rei’s are punchier, more planted, and a little more expressive. I have to say, I loved the extra confidence and expression of the Rei’s but found them ever so slightly boomy and preferred the agility and air of the CH. But, of course, although I used the same Belden power cables and Driade interlinks, the two amplifiers were positioned on different stands. To make absolutely sure, not expecting a world of change, I made room on another Aire platform to position the Rei’s.
Wait… these were the same amplifiers? The earlier noted boominess was gone, replaced by fast-paced incisiveness and agility while maintaining confidence and expression. Holy cow. I knew all too well that the two Artesania stands sounded different, but it now became clear that they were responsible for most of the perceived differences between the two amplifiers. With the CH power amplifier’s gain set to +3dB to match the Rei’s, rather than compensating by the same amount on the CH preamp, they get even closer to one another.
Playing under the exact same conditions, the two amplifiers now sounded so much alike that it became hard to form a preference for one over the other. It also became more challenging to get a good grasp of the differences. One thing that was very clear from the start is just how neutral and transparent the WestminsterLab amplifiers are.
After hours of further comparisons, I wasn’t any closer to describing the Rei’s in and of themselves. However, by now, I have gotten a good handle on how they differ from the CH A1.5. The most obvious difference I heard is what can best be described as a little more carved-from-granite in the bass and very slightly more exuberant (Rei) and a little airier and refined (A1.5). Otherwise, I could not immediately get a firm grip on potential other differences. I should add that this rarely happens. There are always differences, usually several of great magnitude. But this time, we’re talking nuances. At this stage, that is already a massive compliment for WestminsterLab. Honestly, I could swap the amplifiers and continue my review work and casual listening as if nothing had changed.
To my increasing astonishment, successive comparisons using various different tracks did not make it any easier. If anything, I felt the two amplifiers blended into one another, making it even harder for me to tell which of the two was playing. To further prove this point, when walking back into the listening room with both amplifiers switched on, having forgotten which one I left last connected, hand on my heart, I could not tell which one I was hearing. Clearly, both strive for the same thing: absolute neutrality.
But upon persevering, a few differences ultimately emerge. Under equal circumstances, the Rei’s are slightly more confident, immediate, and incisive but also a little drier and less airy, although not dark. Dynamic bursts appear just slightly more sudden. With some speakers, but not the Magicos, I can imagine the Rei’s can attribute to the sound becoming a little dry or direct, or, rather, not quite as dreamy as some may desire. The A1.5, on the other hand, is airier and more fluid and refined, as well as a little more laid back, making it more forgiving as well as slightly less expressive.
There is no perceivable difference in resolution, linearity, transparency, control, timbre, fluidity, or even the flow and soundstaging. Well, perhaps the Rei’s can appear ever so slightly more forward, but that is more a function of their slightly more incisive nature. Heck, the WestminsterLab amplifiers even manage to exert just as tight of a grip on the Magico woofers with the same level of articulation. And that is an absolute first.
Next: Apogee Duetta Signature and Centaur, other amplifiers, and listening to the Quest preamplifier