Pre/Power Amplifiers

To misquote Sly & The Family Stone just a little, Swedish hi-fi company Engström – it only makes tube amplifiers – is a family affair. Founded by engineer Lars Engström and his industrial designer nephew Timo as recently as 2008, the company is based in Lund, just northeast of Malmö, and has its R&D HQ some 600km away in Nacka, south of Uppsala on the Baltic Sea coast. The division of labour in the company sees Lars Engström as chief engineer, having given up work in fields as diverse as navigation, microcomputing and railway signalling systems in 2001 to concentrate on amplifier development, while his nephew is responsible for the look of the products, and the company operations.

The Philips Motional Feedback loudspeaker was one of the great advances in audio technology. Launched in 1975, the series would eventually encompass four distinct generations and remain in production for over a decade, its key technologies jealously guarded by Philips patents [HFN Jul '13]. However, the partnering equipment designed to help these speakers perform at their best is less well known, arguably due to Philips endorsing the use of third-party sources and amplifiers.

Unlike its meaning as a show of arrogance, in a design context a 'conceit' is, variously, 'an ingenious or fanciful comparison or metaphor', 'an artistic effect or device', or 'a fanciful notion'. AGD's £18,000-per-pair Gran Vivace is all three. To understand the utterly bizarre use of a valve's glass envelope as a housing for a solid-state amplifier, think of a similar conceit in another field: smart watches which, instead of emulating Apple's genre-defining rectangle, look like analogue timepieces.

When it comes to prosaic model naming, Classé has it nailed: its latest Delta series preamp, selling for £9999, is called 'PRE', and the matching monoblock power amps at £10,999 apiece, are called 'MONO'. The only other model in the lineup is the Delta stereo power amp, at £11,999, which is unsurprisingly called 'STEREO'.

If life is a journey, rather than a destination, then some brands, Audio Research included, have rather more air miles under their corporate belts than others. From a boutique audiophile business to a period swept up in the fast lane of venture capital, Audio Research has now returned to its roots. It's a gloriously niche brand that understands 'what it does' and is now, once again, driven and engineered by a team that is passionate about serving the diehards of the audiophile community.

The best of both worlds' is an oft-used rallying cry in the hi-fi industry, rolled out to extol the virtues of everything from compact loudspeakers with big bass output to digital network players with phono stage inputs. It's also the self-proclaimed raison d'être of PS Audio's Stellar M1200 monoblock amp. Sold in pairs for £6000, this recent addition to the Stellar range combines a high-power Class D output stage with Class A vacuum tube input, in pursuit of both efficient speaker-driving muscle and spine-tingling musicality.

It's always intriguing to see how a company reacts to the realisation that a technology it has championed is reaching its sell-by date. This was the situation faced by Yamaha in the late 1970s. Since the middle of that decade, its top-end products had made use of Jun-ichi Nishizawa's Static Induction Transistor – more commonly known as the VFET – to great effect. This led to the development of designs such as the B-1 and B-2 power amplifiers, and C-1 preamplifier, all of which are still held in high regard.