POLYTONE

MINI BRUTE II: £340

Many jazz guitarists despair of finding faithfulness in modern day, transistorised amplifiers. The Polytone is a radical exception. Developed with the jazzer and classical player in mind, it melds the portability and compactness of IC design with the warmth and sympathy of the good old, glowing bottle.

The smooth and generous quality that spills from its 16in high frame would be enough to win over many players. Remarkably it goes on to reveal another side of its character — a gravelly rock 'n' roll spirit that makes it a very schizophrenic amp.

American-built and now about 14 years old, the Polytone series includes a host of combos and heads. One of the most distinctive features is the dual clean/overdrive circuitry. The outer ring of the volume control handles the rich clean sound; an inner ring with an integral switch brings in a distorted version and the two are mixable, so you can have a raucous fuzz tone, but still with the clarity of an un-overloaded signal slicing through on top.

Polytone offer a three position dark/brite (yes, they are American) switch that boosts the upper frequencies in one direction and applies a bass lift, treble cut in the other. Not only is it versatile, it's fast, presenting a fruity thrum for jazz chords, but not losing the distinction in each note.

And it looks different. The latest models have abandoned the original furry grey covering that was easily scuffed, in favour of a criss-cross vinyl and a dappled, foam speaker covering. The controls are all mounted on an insert at the back of the amp and they include bass/mid/treble and a sweet reverb.

The back is entirely enclosed, but there's an extra panel near the base that carries sockets for the reverb footswitch, main out and ext-speaker. Two metal capstans exist for you to wrap the mains lead around after the gig and even the plastic cover is carefully thought out. One side is devoted to a zip up pocket, providing room for leads and music.

The Polytone really is a very pleasant surprise — an amp dedicated to musicians in a world of combos built to a formula. There are mistakes. The controls are mounted back to front (you have to walk round the back of the amp to make any sense of them) and 100 watts is a far from realistic figure.

And beware when you first wire it up. The bizarre American cable coding has green for earth, plus a white and a black wire, which due to the design are apparently interchangeable for live or neutral. I tried, and the swap made no difference.

PRO-AMP

Standard 60W: £325

When amp impressarios (ampressarios??) Roger Haines and John Cooper sat down over the drawing board, they were looking for a creature that combined valve tradition and tranny economy. So they amalgamated a solid state pre-amp with a valve power stage fitted with two 6L6s in preference to EL34s. "We found them tougher and more readily available," said Roger.

The result was the start of the Pro-amp range, a piece of all British workmanship, which is now about a year and a half old, but already into many models thanks to the continuing work of its developers.

Along with several other amplifier manufacturers, they've steered away from JBL and ElectroVoice speakers and fitted a Celestion, the workhorse G12-100. The first two can put out extra power, but Celestion have followers who prefer the softer, less clinical quality, even if it is quieter.

They wanted switchable channels each with pre- and master volumes to set up clean and dirty sounds. That can be difficult to do using valves, another reason for the tranny first stage. Channel one is naturally the clean side as two has a few more dBs of gain for gutsier overdrive. A footswitch hardwired into the back panel makes the (silent) changeover and a red LED lights when you're on channel two.

After the Lord made man, he probably knocked off valves while still awake. They give the Pro-Amp a sweet, clean tone that dovetails evenly with the Celestion's slight touch of wooliness down the bottom end and restraint on the treble frequencies. It's not a hard, cutting amp, and the tone controls are adequate, though not musclebound.

So the inclusion of a bright boost is smart, and it seems to lift the very high frequencies, those beyond the range of the treble control giving the sound a sparkly presence (gets the harmonics on their toes into the bargain).

Overdrive is great; anything from mellow romantic lines bearing an underground buzz (plenty of sustain), through edgy chords (very easy to adjust just the right amount of distortion), up to full blown six string earthquakes. It's not, naturally, a jangly Marshall-type fuzz sound, but works better on the throbbing, boomy stuff.

The hottest setting of all was for graceful lead lines when the overloaded power stage provided the merest touch of colour and action to the insides of the notes. The Pro-Amp handled its full 60 watts with no sign of shirking, though towards the top of its range the subtle differences in overloaded tone began to disappear and it blurred into one roaring thrash.

It's a natty looking amplifier. The black vinyl covered case is of chipboard, the speaker baffle is ply and the top has been cut back to give a clear view of the controls when you're looking down at the front panel. They've only missed one. The power lamp is hidden under an overhang, so you can't be sure it's on unless you bend down.

The slim silver front panel, black and silver knobs and black speaker cloth bearing silver threads combine to make it a distinctly racey looking lump of loudness. The rear panel carries a 4/8 ohm switch, extension speaker socket, and a slow-blo fuse. The 6L6s are uncovered but well protected by sturdy cross pieces and overall the construction is solid with the exception of the smallish bolts holding the Celestion in place.

The reverb is okay; it comes in its own plastic mac (as does the amp; a cover is part of the deal) and doesn't clang. This one weighs about 45lb and measures 22½in wide X 17½in tall x 9½in deep.

A high quality, versatile amp at a reasonable price, and one that knows its own mind.