Pre/Power Amplifiers

Each of these three units – preamplifier, two-channel power amp and a power supply to ‘beef up’ the power amp’s performance – is housed in an all-aluminium chassis identical in size and appearance. Pre and power amp are ‘double mono’, the left and right channels both electrically and mechanically separated, with power supply sections, audio circuits and control electronics all in shielded chambers. The new P3000HV preamplifier has a comprehensive functionality that includes an analogue tone processor module to provide bass/treble adjustment, a user-variable ‘loudness’ control to suit your loudspeakers’ sensitivity, and parametric equalisers for tuning your speakers’ bass performance to your listening room. Illuminated touch-sensitive controls allow access to the preamp’s configuration menu, and a headphone amp is built in as well.

Furutech’s Alpha Design Lab range includes cables, headphones and earphones, a portable headphone amplifier and stylish system equivalents of the ADL X1 here. This appears to be a portable miniature music centre, offering USB and iDevice functionality, plus a built-in rechargeable battery giving around five hours of operation. Six top-mounted LEDs display sampling frequency, and there’s a front fascia volume control – which sadly proved just a little too easy to accidentally move when out and about. Those on the Number 41 bus will doubtless prefer the ergonomic simplicity of, say, an Arcam rPAC or Cambridge Audio DacMagic XS, which are truly portable devices.

McIntosh’s original MC275 featured as an ‘Audio Milestone’ [HFN Dec ’10], but what’s reviewed here is the current production version of this most famous power amplifier. It’s the same as the 2011 Anniversary Edition but with stainless steel rather than a gold chassis. Its most spectacular outward feature, described in staid McIntosh tech-speak as ‘small tube illumination for amplifier status operation’, comprises LEDs indicating status or output tube failure. This is a part of a protection circuit system which will also shut the amp down if speaker wires are shorted or there is a gross impedance mismatch.

On seeing Siltech’s pre/power combo you might think it incorporates a separate power supply. In fact, this unusual design splits the power amplifier into separate interstage (voltage gain) and current amplifier sections. The combo’s C1 tube preamplifier (pictured) features a rechargeable battery power supply as does the V1 voltage stage of the two-box power amplifier. Of course, running the complete V1/P1 amplifier from a battery would be wholly impractical, so the P1 is mains powered.

This lavishly-built C600 preamplifier and unusual looking partnering M600 monoblocks [not shown] are TAD Labs’ ‘Reference’ amplifiers. The C600 preamp’s aluminium subchassis is 33mm thick and weighs 15kg alone, designed to resist acoustic vibration and provide a ‘low and stable ground potential’, says the company. Removing the preamp’s top plate reveals its dual mono construction and all-discrete signal path; it’s a fully balanced design. The power supply, with its massive transformer, is a separate ‘hideaway’ unit.

The Virgo preamplifier and Centaur monoblocks reviewed here are models from Constellation’s ‘economy’ Performance range, yet total £72,500. As for Reference prices, we shudder to think… While a pretty enough design, the Virgo is rather anodyne, its greyness John Major-like. A plain-Jane outboard power supply feeds it via two umbilical cables, connecting at the back where you find rows of both XLRs and phono sockets for every input and output – four sources, two sets of outputs and RS232 and USB inputs for networks and firmware upgrades. At the front, the central panel’s 432x230-pixel screen is flanked by rotaries for balance and volume, while other operations are accessed through menus activated by a row of buttons under the display panel.