There’s a welcome absence of ‘glare’ with this amplifier. It presents the music with effortless ease and a deliciously fluid smoothness that sounds natural and right. I’d say it’s best suited to classical music, and acoustic jazz or folk – any music that demands the utmost refinement and truthfulness. It can handle rock too, but some listeners may prefer a less refined amplifier that provides more forwardness and aggression. On the other hand, it can be nice to listen to rock and pop via an amplifier that isn’t burning your ears all the time. Lack of power may be an issue for rock and pop, unless your speakers are very sensitive.
It was interesting to come to the Audion PX25 Mk II after the Musical Fidelity kW-550. The latter has a bigger more dimensional presentation, with greater scale and a wider dynamic range. The Audion is definitely smoother and more refined, with a silky ease and sweet mellow tonality the bigger amp cannot quite match. Conversely, the Audion doesn’t match the MF’s voluminous bottom end. With the PX25, bass is full and firm, but lacks the outstanding depth and breadth of the kW-550. Nor does the Audion project the music with quite the same sense of holographic 3D spaciousness as the MF. But the smaller amp definitely has a subtler tonality.
In use the PX25 runs surprisingly warm. Indeed, it gets pretty damn hot. While it sounds good when first switched on, there’s definitely a change after about fifteen to twenty minutes. The sound grows ever-more relaxed and spacious, reaching its optimum after about half an hour. Residual noise is very low; an important consideration for those intending to use the amplifier with sensitive speakers. With my H-1s I could hear nothing – no hiss, no hum, no buzz, even with my ear right up to the drive units, important given that it will inevitably find itself driving high-sensitivity loudspeakers.
Clearly, in view of the rather specialised nature of this amplifier, any recommendation has to be on a horses-for-courses basis. The Audion PX25 Mk II is not a universal product. In sympathetic situations it will sound wonderful. But, miscast, it may sound terrible. Using it with speakers under 90dB sensitivity is asking for trouble. I see it partnering ultra-efficient horn loudspeakers, perhaps with a vinyl front end. It’s perfect for that sort of system. It will also partner CD, of course, and its innate smoothness and refinement go a long way towards countering CD’s occasional forwardness and lack of subtlety. Its smoothness and natural, open tonality will also help to reduce the bright peaky forwardness that some high-efficiency speakers exhibit. Some Lowther based designs, for example, can shriek a bit (and sometimes more than a bit) with ‘normal’ amplifiers. But the Audion should be in its element here.
The only change I’d like to see is an extra couple of speaker terminals on the back, giving users the option to go quickly and easily between 4 Ohm and 8 Ohm taps on the output transformer. Other than that, I loved it. As indicated, the PX25 MkII is not a ‘universal’ amplifier. But playing “at home” its strengths will make it hard to beat.