Carlsbro's new amp range includes the M150 and M300 power amps and the Marlin 6-300, bigger brother to the 6-150 reviewed here. It offers six independent input channels capable of accepting inputs from either high or low impedance mics, synth and guitars etc, and deliver the mixed result at 150 watts between two speaker outputs.

Controls

Each of the six channels accepts either unbalanced high-impedance or balanced/unbalanced low-impedance inputs, and each has individual gain, treble and bass controls. Two on/off switches for reverb and external effects are situated beside the low-impedance jack.

The main control panel to the right of the unit contains the master volume control and pots governing the amount of reverb, presence and external effects. A 5-pin DIN socket allows for recording onto or playing from a tape recorder or similar equipment.

A dual-spring Accutronics reverb unit is incorporated in the Marlin's design. The combined signal of the channels with reverb selected is fed to this unit, and the overall level of reverb effect is controlled from the main panel. Reverb can be switched on and off by a footswitch connected to the jack which is also on the main panel.

Presence effect can only be applied to the whole mixed signal. This brightens the sound by boosting mid frequencies and is a very handy feature to add character to flat-response microphones and help relieve dead room acoustics.

'FX loop' takes a signal from the preamp, through the send jack to an external treatment such as an echo unit, and the signal is then returned to main-amp stage via the return jack. The same channel can be treated by both 'FX loop' and reverb by depressing both switches of that particular channel's input.

Output

Output is via two quarter-inch jack plugs at the rear of the unit. Each of these plugs carries the same mixed signal. Overall power is 150 watts into 4 ohms. Therefore the optimum performance will be achieved with two 8 ohm 150 watt speakers, although 100 watt speakers or even lower would be adequate depending on quality. Even though the signal to each of the outputs is the same, it is advisable that two speakers be used to avoid overloading. However, if one speaker is to be used it should be remembered that as impedance increases, power decreases. With a single 8 ohm speaker the maximum power would be 105 watts, and ideally a 150 watt speaker should be used.

In use, crosstalk between the channels is quite noticeable, particularly with low impedance inputs. To help keep this and general noise to a minimum, output level should be selected by the master volume control, and the six individual gain controls kept relatively low and used simply for obtaining the correct balance of instruments. For this purpose it would be handy to have some visual indication of the peak levels of each channel but, alas, this isn't available on the Marlin.

Construction

So far, so good. We have a good powerful amp with six independent input channels and two outputs at a price that makes you look twice at the date of the price-list. What else could you possibly want? Well, considering the market that this type of product is designed for would be an amateur/semi-pro band, gigging around as much as possible in an old beaten up Bedford, a good sturdy construction with a strong outer casing is indispensable. Unfortunately, the Marlin is held together by eight screws (four at each end); when these screws are removed the unit simply falls apart (well, at least it's practical for the repairer!)

The Marlin measures 675 x 265 x 110mm, and the top and bottom of the casing are made from single sheets of ½" plywood covered in a vinyl material, without even a support at the mid-point.

However, the internal design of the unit is good. The front panel connections are well laid-out and finished off. Amp stages are segregated from mixing and effects circuits, keeping hum and noise down as far as possible. The amp circuitry is also good and output is protected against short circuit, mismatch, open circuit, reactive load and high-frequency burn-out.

Ease of operation and appearance are excellent. The knobs used on the front panel pots have a large white arrow head which gives a very clear indication of settings that can be seen from some distance; always helpful in a live situation.

Conclusion

With a system such as this you could carry on giving suggestions about what facilities it ought to have, but that is not the point. The Marlin sounds good under a variety of conditions, and is capable of taking considerable sonic abuse without complaint, even if its constructional integrity is a teeny bit suspect. Carlsbro have produced a piece of equipment which allows a band to get up and going on the road, with a mixing facility and a good amp all in one at an extremely reasonable price, and deserve to do well with it.

The Marlin 6-150 carries a recommended retail price of £295 inc. VAT, and further information is available from Carlsbro (Sales) Ltd., (Contact Details).