Integrated Amplifiers

There's a certain amount of extra-curricular activity that can come with using a valve amp. As with their fellow stalwarts of hi-fi – turntables – valve amps present opportunities for setup, tweaking, and maintenance, and for some that's part of the appeal. Balanced Audio Technology's new £9995 VK-80i integrated, however, is intended to be 'plug-and-play', and provide a user experience more in line with its own solid-state models than some hot bottle contemporaries. All the thrills of the tube sound without the fuss? Where do I sign?

The VK-80i is also out to deliver the 'sound' of a pure triode amp without the low power breathlessness. So, in place of classic 300B triodes, the quartet here are 'signature' 6C33C-B tubes – also used in its reference REX 3 power amplifier – set in a push-pull configuration.

This Delaware-based company, now in its 25th year of manufacturing fully balanced amps, rates the VK-80i at 55W/8ohm, albeit with distortion of 3% THD at full throttle. By way of contrast, the higher-spec REX 3 promises 2x80W or 160W in bridged mono mode. Of course, that range-topping amp also totes a £20,000 asking price and doesn't provide the system-streamlining features of its integrated cousin.

Chip Off The Block
The VK-80i doesn't quite have the muscular looks of the REX 3, as it's a 'mere' 41cm deep, as opposed to 60cm, and less than half as heavy, but shares much of its design language. The amplifier's main chassis is pleasingly slim, and manages to pull off the trick of making it look easier to accommodate than it actually is. With output triodes in place, plus the four 6SN7s used in the line/preamp stage, the height approaches 20cm.

Behind the row of 6C33C-Bs sit two circular transformer modules that take the shine off the amp's otherwise elegant styling. And with no protective cage for the hot-running tubes (idle power consumption is 470W), you'll want to ensure children and pets are kept well away. This amp is very much a case of look, but don't touch, and one that demands breathing space.

Fitting the valves is an easy process and setting up speakers and sources is straightforward too – for the latter, choose from the VK-80i's single balanced XLR input, or trio of unbalanced RCAs. One wrinkle, however, is the amplifier's unusual configuration of speaker binding posts – there are dual sets, with labelling denoting which should be used with notionally 'High', 'Med', and 'Low' speaker impedances.

Intelligent Design
As the presence of multiple speaker outputs doesn't exactly scream plug-and-play, it's up to two features of the VK-80i to emphasise its accommodating nature. The first is its 'intelligent auto-bias circuit', which removes the need to manually set tube bias. The second is what BAT calls its 'fuseless design' technology, where thermal and electronic protection circuits replace all but the main breaker fuse demanded by regulation.

The thermal protection, says BAT's founder/chief engineer Victor Khomenko, removes the chance of 'over-stressing' the unit. 'Since our amplifiers don't clip in an obvious, unpleasant way… people sometimes run them into their red zone, without realising it. The thermal protection guards against this.' Meanwhile, output tube current is continuously monitored and the channel disabled above a prescribed limit. Khomenko believes this protection circuit, while avoiding the need to replace blown fuses, is also 'sonically transparent'.

The simplicity of the VK-80i's preamp section is reflected on its front panel. The small display window signifies input and volume, the former by number (there's no option to rename sources here), and adjacent to this are small buttons for input selection, plus the amp's resistor-ladder volume dial. The supplied all-metal handset is similarly light on functionality, but therefore easy to get to grips with. Use it for source selection, volume, mute and fade, and adjusting the brightness of the amp's display.

Feel The Heat
Once its tubes are glowing the VK-80i puts on quite the show, but it took me a while to fully appreciate its talents. This isn't an amplifier with an obvious, deliberate tone or voicing. As with the company's earlier £11,995 VK-3500 hybrid amp [HFN Sep '21], there's no sense of artificial warmth here. Nor is there an extravagant bass. What the VK-80i does, instead, is pepper you with details, often so subtly that at first you don't realise. It's articulate and revealing without shouting about it, super-smooth when needed, grippy and controlled when push comes to shove. It's an exhilarating listen, although not a monster amp, so partnering speakers should be chosen with care.