Pre/Power Amplifiers

Musical Fidelity is no stranger to big power amplifiers. Its top-of-the-range monoblock, the £3599 M8s-700m, claims a 700W/8ohm output and weighs in at 35.5kg, and the company sells a stereo model in the M8 series too, the £3999 2x500W/8ohm-rated M8s-500s. But perhaps what few expected from the brand, considering its range also consists of DACs, streaming amps, phono stages and CD players – everything a two-channel audiophile could want, in other words – is a seven-channel amplifier. Which is what we have here, in the shape of the M6x 250.7.

Until this year, the flagship power amplifier in PS Audio's stable was the BHK Signature 300 [HFN Jul '16]. Still on sale, it bears the initials of Bascom H King, the veteran designer (Infinity, Constellation Audio and more) who was given license by the Colorado-based company to engineer a high-output monoblock amp around his favoured tube/solid-state hybrid topology. Six years on from launch, the '300 model has been relegated to second-tier status, replaced by the PerfectWave BHK M600.

Boulder's founder and chief engineer Jeff Nelson gained his first audio engineering experience with studio mixing desks and the design of a professional cartridge tape unit. This led to a constructive interchange with the late Deane Jensen, the audio transformer wizard and the originator of a classic 'operational amplifier'. This was not an integrated circuit but one implemented at good power and wide bandwidth via the use of discrete devices.

Unlike the traffic on the motorway for which this stereo amplifier is definitely not named, Canadian manufacturer NAD is rolling along at pace. The M23 auditioned here, available in just a silver finish, is its latest amp to feature high-performance Purifi Eigentakt Class D technology, following in the footsteps of the £3999 M33 BluOS-capable integrated [HFN Aug '20], the seven-channel £4499 M28 power amp, and the more affordable £1749 C 298 stereo amp [HFN Oct '21]. That NAD should have chosen to adopt Eigentakt modules for a trio of models before upgrading its flagship two-channel Masters series power amp is perhaps something of a surprise. But it proves to have been worth waiting for.

Based some 40 minutes west of Düsseldorf, SPL sounds like an attractive prospect for those who like their music loud – though in this case the name has nothing to do with Sound Pressure Level, standing instead for 'Sound Performance Laboratory'. Mind you, the promise of room-shaking raises its head again with the new flagship power amplifier in the company's domestic – or 'Professional Fidelity' – range, which promises 'Mastering Grade Listening'. The new Performer s1200 (£6499) may only measure a smidge under 28cm wide and a little over 20cm tall, making it a tiddler in the pantheon of high-end stereo power amps, but it's still capable of a claimed 300W/8ohm, rising to 520W/4ohm. This should be more than enough for even the most demanding speakers and level-hungry listeners.

Look at the latest iteration of Lindemann's network music player, the £3450 Musicbook Source II, and you'd be forgiven for thinking that nothing much has changed [HFN Jun '20]. This is still a compact unit, just 28cm wide and a mere 6.3cm tall, with nothing much on show save a power/standby button sunk into one end of the top-plate and an edge-mounted volume control, with a push-to-mute function, at the other.

Avoirdupois aside, Dan D'Agostino Master Audio Systems' Momentum M400MxV monoblock just may be the least fussy or fiddly power amp one can aspire to in the extreme high-end. Of course, something cute and tiny like a PS Audio Sprout [HFN Feb '15] or Quad Vena [HFN Jan '15] can be lifted with one hand and requires no degrees in electronics, but that's 'real world' gear. At £90,000 per pair, the M400MxVs are as exclusive as it gets, and such a strong physical presence is de rigueur.