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Sonic Gear i-Steroid review: Sonic Gear i-Steroid

The hearty, reassuring glow of valves was once a common sight inside electronic equipment and Sonic Gear has tapped into audio nostalgia with this single-valve amp. Its design is clearly inspired by the iPod, although you can use it with other players, and it produces a subjectively 'warm' sound

Chris Stevens
4 min read

The hearty, reassuring glow of valves was once a common sight inside electronic equipment. These little beacons to the electrical age still hold a romantic appeal today. They're the open-hearth fire of the information revolution. Many modern musicians use valves in their Marshall stacks, and some of the most sought-after studio equipment is packed full of the bright glass bulbs.


Sonic Gear i-Steroid

The Good

Simple setup.

The Bad

Valve does little to enhance the sound, though it does colour it in a way that has subjective appeal to some listeners.

The Bottom Line

Transistors overtook valves decades ago, but for some audio equipment (notably guitar amplifiers and some microphones) tubes give a warmer, subjectively more enjoyable sound. It's a struggle to justify a cheaper valve stage in an entry-level iPod amplifier, but the i-Steroid gives it a decent try

The Sonic Gear i-Steroid uses a single valve to alter the tone of the music amplified from your iPod (or other MP3 player). Purists will have several problems with the £130 i-Steroid's approach. First off, the valve is part of the unit's sub-woofer component. Valves are highly sensitive to vibrations, so it seems odd to put the valve stage in the most vibration-prone part of the unit. Secondly, valves vary wildly in quality and simply using a generic valve will offer little benefit.

So, does the i-Steroid fall foul of the cruel hand of physics, or is this a rare exception to the general rule that inexpensive valves offer little advantage over solid-state electronics?

The iPod's influence here is clear. The i-Steroid's integrated amplifier-sub section looks very much like an iPod that's been passed one too many saveloys through the school railings. It's about the size of a car battery. What looks like a Click Wheel on the front of the unit is in fact a simple volume rocker.

The i-Steroid's valve is very much of the "Hey! Look at me!" variety, and sits in pride of place at the top of the unit. The Sonic Gear designers have made it look like some precious crystal at the top of a gleaming white monolith. This gives the impression that, like the Golden Idol on the plinth at the beginning of Raiders of the Lost Ark, touching it will cause a giant boulder to chase you to a grisly death. To think that valves were once considered ugly enough to hide deep inside a radio chassis. Now they're revered.

The i-Steroid's speakers are equally lardy: each one is about the size of a house brick. There's a solid feel to the components -- they're made from a dense plastic similar to the type Apple used on the iPod Hi-Fi. The cones are exposed, making them vulnerable to damage but also improving acoustic transparency (not that this tends to be an issue at the more affordable end of the hi-fi market anyway).

The i-Steroid also comes with a remote control, although our review unit didn't, because a rival technology reviewer had apparently lost it somewhere.

The system is very easy to set up and includes all the cables you need to get it running. The speakers use conventional bindings and there are generic phono connectors to patch in the device you want to amplify (in our case, an iPod).

Valves rely on the principle that a powerful current jumping between two metal elements in close proximity within a vacuum (the bulb) is easily suggestible while travelling in the gap between the two elements.

By inserting a thin gauze in the gap between the elements and sending a weaker current through it (for example, the input from an electric guitar pickup), the stronger signal will pick up the characteristics of the weaker one. This is the basic idea behind valve amplification. Valves were superseded by silicon in most electronic equipment, but they are still used in specialist audio equipment today because of the subjective sense of warmth and tone they produce.

The i-Steroid uses a single valve, and, as you'd guess from the cost of the unit, it's not an especially refined one. However, the rules of physics governing audio output do not state that expensive equipment is an absolute pre-requisite of good sound. Accepted wisdom is, however, that solid state beats valve technology for accurate sound reproduction until you start spending big money on some very carefully crafted valves.

The i-Steroid sounds fine with most music. A small boost in the low-end and the psychosomatic influence of the big glowing bulb in the centre of the unit gave some tracks a subjectively 'warmer' feel than on our flat-response studio reference amp and speakers.

To be brutally honest, it sounds just like a single-valve pre-amplifier at this price point should sound. You're getting a slight tonal change in the amplified sound that could be more easily and accurately achieved by solid state. There's no reason not to buy the i-Steroid -- it sounds decent enough -- but the valve is essentially an attractive gimmick. Audiophiles will not be impressed, but the rest of us can sit happily listening to Coldplay and staring at the pretty glowing bulb.

Edited by Mary Lojkine
Additional editing by Nick Hide