When it comes to power amps, you can't have too much of a good thing. And that's never more true than with the QSC MX3000a - a heavyweight in every sense of the word. Ian Masterson straightens his back and listens...

Everything tends to be bigger and better in California. So when Costa Mesa-based manufacturers QSC decide to build a new power amp, they don't dabble with puny wattages in the three-figure bracket. They go for a seriously massive 1600 watts-per-side into 2 ohms, and set about constructing it in the toughest, heaviest box they can possibly build - 31 kilograms, no less.

Make no mistake: this is not an amp for the fainthearted. The MX3000a is actually the most senior model in the MXa range (which comprises the MX 1000a, MX 1500a and MX2000a), and its statistics reflect its power-happy pedigree. Packed into a 3U high, 19" wide, 18" deep case, this unit can pump around 3200 watts out into 2 ohms when operated in bridged mono mode. For those of you who prefer a more typical load of 8 ohms in dual mono, the output per channel will still be a mighty 850 watts. Scary, isn't it?

QSC have always made sure that their amplifiers are impeccably constructed and finished, and the MX3000a is no exception. Once you (and your mate) have managed to manoeuvre this beast out of its equally-resilient cardboard packaging, you will undoubtedly pause to marvel at its attractive matt black finish and delicate blue livery.

For my money, the MXa's lines are much more appealing than the more 'rock'n'roll' USA series - and this extends into audio character too, as we shall see later. The front panel boasts an impressively beefy neon mains rocker, (sounds like the cover of Guitarist magazine - Ed), while each channel has an input gain rotary (usefully marked in dB) with Power, Signal, Clipping and Protection warning LEDs.

Connections

Round the back, nestling on either side of the centralised cooling fan, are to be found the input, output and mains connections. Taking the latter first, I was interested to note that QSC have chosen a captive mains lead for their power supply uptake, rather than the more common detachable IEC connector.

In the case of the MX3000a, this is probably wise, since someone unfamiliar with the massive output of this amp could by chance plug in an IEC lead incapable of dealing with the resulting mains load. However, I would have preferred to see a mains fuse accessible on the outer panel, rather than buried inside the casing.

Your speakers are hooked up via a pair of standard red and black binding posts, which offer an aperture suitable for all but the thickest cable. Perhaps it would be better, 'though, if amp manufacturers started to adopt a common output (let alone input) connection technology; binding posts are all very well, but you still can't beat a nice pair of Neutrik Speakons.

The input strip is slightly more comprehensive, being accessible on a set of screw terminals and 1/4" jack sockets (both of which offer balanced and unbalanced operation). XLR sockets are not available as standard, but can be added as an option courtesy of the nifty removable expansion plate. Modules can also be inserted here, as and when they become available, which provide remote indication of the warning lights and status of the amp - useful if you're running a bank of MXa units in a large gig.

Internally, each channel has its own power transformer, and bi-polar multi-rail power supply. These are mounted toward the front of the chassis, keeping the weight balanced on the front mounting lugs, and reducing the risk of your rack twisting or toppling. All the circuitry is cooled by a vari-speed fan which speeds up as the internal temperature rises, and draws air in from the front of the unit and out through the back. Should things get too hot for even the fan to handle, a thermal protection circuit comes into play, first limiting, then muting the output if the temperature rises above 85 degrees C.

Road test

Of course, the most important aspect in choosing (and indeed reviewing) any amplifier concerns how it sounds in practice - and the MX3000a sounds great. I was interested to test this meaty device for the purposes of driving some large JBL sub-bass PA cabinets, and played a correspondingly wide range of bass-heavy dance music through it - straight from a CD player and turntables.

This machine can handle deep, rolling analogue bass with ease; the smooth sound flows from the speakers undistorted and untarnished. Further up the frequency spectrum, playing some chamber orchestra music through more forgiving midrange and top cabs revealed how the MX3000a lacks that irritating rock'n'roll grittiness found in the majority of American amps.

The sound is much purer and more refined. Well, as pure and refined as one can get at 1600 watts per channel. My only concern was for a slight dulling of the upper-midrange (for example, two octaves above Middle C on a piano), but this is hardly noticeable in a pumping club or thrashing gig in any case.

If you're in need of a major-league, major-power amp at a reasonable cost - and particularly so if you want to put 'oomph' in your bass bins - then make sure you try out the MX3000a. If your needs are slightly more modest, opt for one of the models lower down the range. Just make sure you get that mate in to help you lift it.

The essentials...

Price inc VAT: £1880

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