By now - 15 years before the mast(head) - most regular readers know what pushes my buttons. So is it any wonder that reviewing the Nagra VPA all-tube power amplifier is one project for which I was prepared to fight? It's right up there with the Finial turntable, the Sonus Faber Amati, the Marantz valve reissues and the Audio Research Reference components in sheer 'wantability' or curio value, and even a jaded old whore like yours truly can still get it up
£8495, though, isn't quite the price I expected. Eight-and-a-half grand is serious money by any standards, but I would not have been surprised if this most enticing of products had a five-figure price tag. No, I'm not spending your money for you; I'm just being realistic. If you factor in Swiss-ness, Nagra-ness and any other 'ness' you care to name, you'll see that the VPA has the prestige, pedigree and - as will clearly emerge - performance which make it a high-end product worthy of high-end prices.
For the Nagra faithful, it means no more waiting for a mate to the PL-P pre-amp, the jewel which started this particular DNA strain. There it was, an all-valve pre-amp from a company with (1) no track record for tubeware, (2) no patience for audiophiles and (3) the sort of reputation enjoyed only by makes which deal exclusively with the professional sector. In Nagra's case specifically, it is supremacy in the fields of on-location tape recorders (a film-industry standard, in fact), spy tape recorders, satellite broadcast receivers and other niches light-years away from the audiophile tendency.
Stuffy Swissness, though, turned out to be more flexible than any could have imagined. When both the US high-end community responded enthusiastically to the company's digital open-reel AND one of the Nagra's designers felt that he needed a new phono stage, the PL-P was born. Success way beyond Nagra's expectations - the Swiss seem sceptical and mildly pessimistic if nothing else - led to further involvement with pure audio, hence the VPA.
Now let's not get too carried away here with Nagra's seeming conversion to the ranks of the Good Guys. The company is still subject to Swiss behavioural patterns, high-end audio will forever remain a teensy part of its output and Nagra exposed a truly conservative streak by producing - as an alternative for or sop to conservatives - a solid-state power amplifier as well...just in case Nagra started to appear to 'radical'. But R&D Manager Schlup remains a rebel in Swiss terms, which explains the VPA's topology.
While the PL-P at least resembled a Nagra tape deck sans spindles, the VPA looks like no other amplifier on earth - let alone a Nagra product. And that's despite the prominence of one of the company's trademark gauges on each chassis, as specific a giveaway of something's origins as, say, a black horse on a yellow background.
Amusingly (and in keeping with the Swiss' reputation for secretive banking practices), the VPA is deceptive in so many ways, starting with the valve complement. Per amplifier, the tube line-up consists of two ECC83s and a Mullard ECC82 in the input section and two 845 output tubes. More to the point, those 845s stand proudly and shamelessly on the top plate. And yet, despite the VPA featuring a brace of the cherished triodes which are probably second only in popularity to the 300B for pure SET credibility, it is
The transformer complement? Proprietary designs conceived to avoid low-frequency saturation and high frequency ringing, two mains and one output toroidal per unit, placed at the bottom of the cabinet to aid the centre of gravity and positioned vertically because the case is so narrow. And the 110x300x370mm (WDH) machined-from-solid aluminium cabinet
In reductio, it's a pure Class-A design rated at 50W into 4, 8 or 16 ohm loads, suffering zero negative feedback. The 845s are, of course, directly-heated, thoriated tungsten triodes, the input impedance is 100k ohms, and the sensitivity 400mV for its rated output into all three impedances. An abundance of protection circuitry and overkill construction do not obscure the realisation that the VPA presents a clean path for the signal. But then you notice the details which remind you why you went Swiss. The front panel, for example, bears a pro-grade, three-position rotary switch providing on, off and mute in-between, its style and feel identical to the rotaries on the P-LP. The Nagra meter? This time it's called, instead of a 'modulometer', the Nagra Load Match Meter, and it monitors the operation of the 845s by indicating peak DC voltage and current draw on the output tube anode. Nagra says that this makes it easy to 'spot speaker mismatch (sic) and suggest corrective action.'Read more about the VPA on Page 2.