Pre/Power Amplifiers

Something for the high-end user with a sense of fun – Metaxas' Marquis 'Memento Mori' headphone amp marries form with function and the result is rather jolly. Er, Roger.

Headphones now rule – period – and as a vivid illustration of the current profusion of cans, I was staggered to see, at a store in Tokyo, a selection of something like 1500 headphones, and with plenty of high-end brands notable by their absence.

Naim Audio’s first product, the NAP 160 power amplifier, was introduced in 1971; the NAP 250 appeared in 1975. It was technically unusual in that it used a strictly regulated power supply, whereas the vast majority of power amplifiers, unlikely today, typically made do with an unregulated one. Arguably, the NAC 12 preamp was even more unusual than the NAP 250. In ultimate form it required a standalone external power supply – the SNAPS – at a time when such an arrangement was virtually unheard of.

Here’s a stylish new Meridian product right in the mainstream: a headphone amp/USB DAC with optional outboard PSU. It wouldn’t be a Meridian, though, without having some novel features. The cases are interlocking aluminium extrusions, double-skinned to enhance screening, and having no visible fasteners holding it together – clever. The PPS power supply is not dedicated to the PHA headphone amp but provides five 12V/500mA DC outputs on mini-DIN sockets, each incorporating dual-stage linear voltage regulation, for powering other Meridian products as well.

Schiit products benefit from a Scandinavian nomenclature – Asgard, Bifrost, et al – so, should this stunning little Magni headphone amplifier prove tempting, you needn’t approach the salesman with the embarrassing request, ‘Do you stock Schiit?’ As its company founders are seasoned designers of [quote], ‘fully balanced differential power amplifiers, fully discrete I/V conversion stages, audiophile D/A converters, relay-switched stepped attenuator volume controls in preamps, etc,’ they could have launched Schiit with whatever product genre they liked. Being savvy, they chose headphone amps. Schiit works with ‘simple, discrete circuit topologies’ for the analogue sections, while its DAC products feature ‘innovative bit-perfect management systems’. It also uses Class A amplifier designs ‘where practical – and single gain stages when possible’.

At last, Levinson’s flagship No53 monoblock amplifiers [see HFN Jan ’11] now have a Reference-status preamplifier with which they may be rightly partnered. The No52 is a two-chassis component designed with meticulous attention to detail both in its topology and in features that offer comprehensive system configurability. The rationale of this approach is to isolate the pure analogue audio circuitry from any possible source of pollution: it physically separates the power supply and microprocessor-driven controls from the audio electronics contained in the larger chassis. Volume control is via a precision ladder resistor network with fine gain adjustment in 0.

User-friendly features are a major aspect of the current VTL Signature Series, including the power amp reviewed here. Based on four 6550 output tubes per channel, it has newly-designed output transformers, a larger power supply, and the Signature Series control electronics. When running, the tubes can be seen discreetly glowing through the smoked glass front window. (Our sample was fitted with KT88s, an option that adds £200 to the price.

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.