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NVA AP50 Amp Reviewed

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3 Stars
Value
3 Stars
Overall
3 Stars

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How refreshing it is to see, amidst a plethora of amps so cluttered as to be rococo, a return to good old-fashioned British minimalism. Not that NVA is completely innocent of the charge of producing what in the world of watches are called 'complications'; the company's flagship models are as ornate, stylised and over-engineered as any Japanese single-ended triode amplifier or computer-driven solid-state behemoth from America. But NVA's AP50 integrated amplifier is a dose of sanity as the hi-fi buttons'n'knobs count increases with the number of surround-sound formats on offer. This thing is so cleanly styled that it'll confuse those introduced to audio through an A/V receiver of post-1990 construction.

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Then again, it's not surprising, as Richard Dunn is this industry's self-appointed bullshit filter, author of numerous missives protesting one thing and another. But he does practice what he preaches, and the AP50 is as free of taurean faeces as is possible without eliminating basic operations. Even the on-off toggle has been relegated to the back panel, which houses only the requisite (gold-plated) sockets for the six sources, the tape loop ingress and egress, and speaker sockets which accept only the near-to-extinction banana plug. The front panel bears but two large knobs, one a nicely weighted device for altering level, the other for selecting the source. As the front panel is made from black perspex, NVA has used this to good effect by including a tiny red LED to indicate on/off status in a most tasteful manner. But it won't cause palpitations among those who get their rocks off by switching off the lights to watch their hi-fi systems' luminous capabilities. All we're talking about is a tiny red dot.

Er, that's it. The unit is so clean and simple and nicely finished that, were the dealer to cover the NVA logo, you could easily mistake it for a Densen integarted amp or some other device of the Scandinavian persuasion. This amplifier is a tonic for those fed up with clutter, a throwback to 1983 and the days when anyone using a source other than a turntable was deemed an . Only this is 1996 and Dunn has a wicked sense of humour: phono is optional.

In the form which arrived for the review, the AP50 bore six identical line inputs, hardwired to the selector switch. NVA - as cable-sensitive a company as I've ever faced - uses silver alloy with a PTFE cover at this stage. The output of the source switch is fed to the volume control and tape sockets, again via silver wire. The potentiometer is an ultra-high-quality 'cermet' type using precision metal film resistors , '...as a by-pass to simulate a log law.' Again through hard-wired silver cabling, the signal is fed to the amplifier PCB.

Although I'm loathe to cite a revival in passive pre-amplification despite this technology rearing its head in all manner of unlikely places, the front-end of the AP50 completely passive, with Dunn pointing out that there's a wee trade-off in using the cermet pot. Apparently, the cermet tracks are not as smoothly finished as conductive plastic film or carbon tracks, so there's a form of 'surface noise' just audible when you alter the volume. But Dunn argues, though, that cermet provides far better sound quality than the alternatives, so the residual noise during level changes is a small price to pay for sonic superiority. And besides, you do your listening when the levels are set and the rotation has stopped. (No, let me guess: There's a rare breed of Tasmanian audiophile which listens to music with the volume constantly changing...)

Because it's fed by a passive pre-amp, the input stage of the power amplifier section has minimum inductance and capacitance, and a current mirror is employed to guarantee that the voltage rails track each other correctly. Overkill has been applied in the power amp's driver stage in that both the current and voltage amplifiers use devices hefty enough to act as output transistors; the actual output devices are 12 amp Darlingtons, two per channel and responsible for its 60W/ch rating.

NVA also eschews in this product any form of protection circuitry, which should be kept in mind when you first read the detailed instructions and warnings of locusts and boils should you behave in an unnatural manner. Grounds for turning you into a pillar of salt include short circuits, bi- or tri-wiring, running lengths greater than 10 metres, using 'unapproved cables', high capacitance or Litz wires, or listening to Babylon Zoo CDs. Indeed, so fearful was I of incurring the wrath of Dunn that I didn't stray from using the supplied NVA cable.

Listen: there's an actual list of acceptable wires which accompanies the AP50 identifies seven precise makes and models of wire at the top of the tree (two from NVA, all types of DNM, etc), and a roster of 22 others which pass muster. And just in case you think that Dunn is kidding, the sheet also states categorically that, 'If any other cables than the recommended are used it will invalidate our guarantee.' And should you entertain the notion that such a stipulation is illegal, I think you'll find that the warning qualifies as valid instructions for use, and to ignore it would be like expecting a car manufacturer to pay for a new catalytic converter when you've been using leaded petrol.

Read more about the AP50 on Page 2.
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