Not the most fortunate of names, is it? Conjures up visions of child psychiatrists handing out crayons from the back of a No 32.

As previewed in our December ish, there are a lot of personal headphone practice amps winging their way over from Japan, Roland made it slightly ahead of the rest and selected a title which refers to the interconnection system around which the Playbus is built. Let everyone else go for the 'Headwatt' and the 'Earamp'.

In fact, Roland seem unshakeably obsessed with the principle of interlinking; witness their enthusiasm for MIDI. The 'bus' suffix has a similar meaning to the 'buss' found on a four-track cassette recorder — essentially, one route which can take several signals, but more of that later.

The Playbus, or HA-5 if you really prefer, follows in the footprints of Tom Scholz' Rockman. It's the same shape and size as a personal cassette player, but inside the grey plastic case is a distortion circuit and chorus unit which doubles as a slapback echo generator.

It's all powered by four penlight batteries. Most of the controls are on colour coded sliders set into one face of the unit while the sockets fit down a long edge, and the three blue switches for on/off, chorus, etc. sit on the top. The sliders cover initial gain/distortion, master volume, bass and treble, buss volume, chorus speed and depth.

The chorus and echo share their circuitry so you can only have one at a time, and the Playbus can be switched between clean and overdrive.

We could immediately plunge into the technical aspects of 'bussing' here, and I could nip out for a cup of tea while the office Terrapin wrote up the catalogue. But before any other considerations, the Playbus first has to succeed on sound. And it does.

With the distortion off, the tone is clear, clean and loud, though winding the master volume to its limits eventually overloads the headphone themselves. Chorus, she smooth and in stereo which is a distinct aural advantage since it spreads your guitar across your forehead like runny butter. Plentiful variety of effects from jangly 12 string imitations to slow, medium and fast Leslies.

The tone sliders are a necessity. I had them up full all the time but a guitar with meatier humbuckers might not require so much bass boost.

In the past, headphone practice amps have left me unthrilled, mainly because what you finally hear seems to be cramped and confined. This is not a 100W Marshall, you say to yourself, this is a scrap of foam rubber rammed into my lughole.

I admit I haven't tried the Rockman for any length of time, so it might be capable of a similar response, but the most impressive aspect of the Playbus was its size. Not the dimensions of the case, but the sound.

Once you've selected the slapback echo, your guitar seems to step back by 10 feet. And with even the slightest touch of distortion adding to the ambience, the results are full and uninhibited. Turn the echo off and the distortion reverts to being an average and somewhat lacklustre fuzz. Yet with the slapback returned (again in stereo)... to be honest I slipped the headphones off at one point to check that a cunning Roland employee hadn't flipped on an amp in another room.

The lightness of the 'phones contributes to this easy feel, though if you start nodding the bonce too furiously, they'd probably go for a rendezvous with your boots.

Now we've worked our way up to the skull, it's time to mention the Playbus' other gimmick — a built-in talkback microphone. It swings out from the left 'phone and will glide up and down in front of you (from forehead to Adam's apple) and the arm itself rotates to place the small microphone just in front of your mouth. And (smart this bit) the mike only turns on when it's around the middle of its travel. Move it downwards out of the way and you disconnect it from the Playbus, cutting out any strange rustlings or heavy breathing.

The initial reaction is to sing along with whatever you're playing, but the principle use is as a talkback mike. Two leads run from the phones, one blue (the mike), the other black and they connect to mini-jack sockets at the side of the Playbus. An extra mini-jack handles the output from a cassette player so you can play along to tapes, and another standard socket is the grateful recipient of your guitar's outpourings.

The final jack socket is where we came in — the Play 'bus'. It's a stereo connection with one channel accepting the guitar and talkback information from your mate's HA-5 and the other directing all your strummings and chattings to his. Nothing worth getting Einstein up for, but a simple trick that converts the Playbus to a rehearsal/song writing device instead of a solitary one-man machine. Other headphone amp manufacturers have a similar scheme but need two or three sockets to do it, and don't have the extra mixing facility which the Roland's buss volume slider allows. Should all systems of communication fail, a buss mute switch cuts back the overall volume as long as you have your finger on the button. Thus you can talk to producers, parents, plants, etc.

That socket also enables you to use the Playbus as a straight effects unit for an external amp. My only reservation is the case — it's certainly light enough to be clipped to belts or hung round shoulders and barely be noticed, but it's NOT built as ruggedly as a foot-operated effects pedal, so don't treat it as one.

£175