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Energy Technology VKP1

Valve Keyboard Preamp

Originally designed to add that authentic growl to rock organ sounds, the VKP1 is far more flexible, as Paul White discovers.

The VKP1 was first conceived when keyboard guru Nick Magnus happened to mention to engineer and ex product-specialist Dave Kenny of Energy Technology that he needed a valve preamp to add that authentic raunch to his Hammond organ sounds. Shortly afterwards, Nick was presented with a beta test model of the VKP1.

In concept, the VKP1 is very simple; it has two all-valve audio channels, each containing two E88CC valves, where the level of gain, and hence distortion can be set by the user. Audio connection is via unbalanced jacks. Each channel also features a Presence control and an output Level control. Other than that, there's a hard bypass switch for each of the channels and an Energy Technology logo which lights up once the valves are at their working voltage. There's no fancy EQ, no effects and no speaker simulator circuitry — what you're paying for here is pure valve distortion!

Valves are famous for their sound, but notorious for noise and hum. Careful circuit design has helped minimise noise, while hum has been taken care of by stabilised power supplies for both the valve heaters and the HT. The circuitry is mounted on a combination of tag strips and dedicated PCBs, while the valves are fitted to ceramic bases, which eliminates the charring and arcing problems that used to beset bakelite valve holders.

At switch-on, the valve heater voltage rises slowly to avoid thermal stress on the heater filaments, and only when the heater voltage is up to level is the HT applied. In the event of a heater supply failure, the HT will remain off so as not to strip the cathodes of the valves.


The input stages of the VKP1 are designed to accept the output from most keyboards with no need for additional amplification or DI boxes, though some low-output keyboards would benefit from more gain. However, a DI box or preamp is recommended for guitar or bass use. As the channels have independent controls, two mono signals can be processed using different settings if required.

It seems that Energy's elaborate power supply arrangements have really paid off, as the level of hum and noise is well below what you'd expect from a typical valve amplifier designed for musical applications. High settings of the Gain or Presence controls tend to bring the hiss level up slightly, as is to be expected, but its performance is still quite respectable.

Tonally, the sound processed via the valve circuitry comes out as being warmer in the mid-range, and less toppy when compared with the bypassed setting, though the top end can be restored by advancing the Presence control setting. At low Gain settings, the sound remains subjectively clean, the main difference being in perceived tone, but as the Gain setting is advanced, the familiar raw overdriven valve amp sound becomes evident. Used subtly, this effect adds exactly the right amount of raw edge to conjure up the classic rock organ sounds mentioned earlier, and you don't need a Hammond to do it — any decent synth organ patch with a touch of Leslie effect seems to work well. These same 'medium' settings are also great for warming up bass sounds, making string pads more syrupy and generally fattening things.

Crank on more Gain and the sound takes on a definitely menacing edge which can work beautifully on single-note lead lines, but tends to be a trifle 'spitty' on chords. These high settings are one way of recreating those Jan Hammer-style guitar sounds using a synth.

Criticisms of the VKP1 are few; I felt that some of the heavily overdriven sounds were just a touch too crunchy, possibly due to the lack of any speaker simulation circuitry, but used with care, the overdrive effect is very musical.


The asking price of the VKP1 might seem high for what is essentially a fuzz box, but real tube distortion only comes from real tubes, and though some of the better solid state devices come very close, I'm sure that those who insist on the real thing will consider the VKP1's price quite reasonable — and this is the only dedicated unit of its type I have come across. Though there are similar preamps made for guitars (which can be used on keyboards), some cheaper and some offering additional facilities, they're not stereo, which still leaves the VKP1 as the most cost-effective solution for a very specific application. Furthermore, the low hum and noise levels produced by the VKP1 make it suitable for professional recording applications. As niche products go, this one is very well conceived and is packaged in such as way as to be taken seriously by studio professionals as well as keyboard players and home studio owners. And it's built in the UK by people with studio engineering backgrounds, which must help in ensuring it hits the mark.

Further Information

VKP1 £389 inc courier delivery on the UK mainland.

Energy Technology, (Contact Details).

VKP1 £389

Authentic valve sound.
Easy to use.
Only dedicated valve keyboard preamp on the market?

Sound can be a little rough at high overdrive levels. An internal speaker simulator might have helped.

The VKP1 can be used not only to create classic overdriven organ sounds but also to give a new 'flavour' to modern synth patches


When Dave Kenny first asked me what I thought would be a good valve-orientated product with which to launch Energy Technology, I must admit to an entirely selfish response. Inspired by the recent purchase of a Hammond XB2 organ, a wonderful simulation of the mighty C3, I felt sure something could be made that would offer the power and colouration provided by the valve preamplifier of a real Leslie cabinet - and with total authenticity. Such was the original concept; a valve preamp for organs. Dave and Jon Griffin put together an initial prototype, and the first test took place. It became immediately clear that the VKP1 could be a real all-rounder. It sounded great on the Hammond and soon we were putting all manner of devices through it. Sampled basses and guitars, pianos, even drums; a creative result seemed possible with almost anything. Quite apart from the obvious valve overdrive, many sounds benefited from very subtle processing, giving digital synths a pleasingly different aspect.

Having used the prototype for some while, I began to wish for a second unit, so that both the Hammond and, say, a bass, could benefit from this treatment. Subsequently, the idea of a stereo unit with identical but independent channels came into being. This led us to try linking the two channels together to see what sort of obscene results could be obtained. Full shred! Scarcely a mix goes by, now, without the VKP1 providing a little subtle (and not so subtle) magic to the proceedings. With analogue synths very much in vogue, the VKP can put pseudo-analogue sounds made on digital instruments into a more suitable perspective, and can be an invaluable tool for both live and recorded music. Nick Magnus

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Alan Parsons

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Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.


Sound On Sound - Nov 1993

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> Alan Parsons

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