Review: MC2 Audio E90

Very high power amplifiers (muscle amps) are one of the more exciting developments in the ever-evolving world of professional audio. They don’t get their name from their size or weight, but rather, from their output power figures that would have been a physical impossibility only a few years ago. One of the companies leading this development is MC2 Audio, an English company involved in amplifier manufacture since the mid ’90s. One of its directors, Terry Clarke, was previously co-founder and technical director of Klark Teknik and in 2007 MC2 merged resources with XTA Audio and Quested Monitoring Systems. MC2 products have recently been made available in Australia through CMI Music & Audio.

Designed for touring or installation applications, the E series amps have been available for nearly five years and the E90 is the newest and most powerful of the series. How powerful? Try 8000W into 2Ω from a 2RU amp weighing just 11.5kg.

This prompts two questions: One, are the output figures real or is this another example of the type of exaggeration common in the domestic audio retail market? The ghetto blaster with the large, bright ‘800W’ sticker on the front comes to mind. And two: why do we need amps with this sort of output power? According to an independent bench test, the output figures are indeed real, and without having the capacity to test this sort of wattage myself, I’ll assume these figures are truthful and accurate. Producing that kind of output draws enough current to melt your average household electrical wiring system, so don’t bench test the amp at home whatever you do!

The answer to the second question lies in the way amplifier and speaker design – along with production logistics – are becoming increasingly inter-connected. The desire for more powerful amplifiers is being fuelled by a combination of improved power handling in speaker drivers and from multiple speaker systems, particularly line arrays that can require significant amounts of power per band. Modern sub-speaker designs also rely on high power to get them moving properly and the headroom available from muscle amps allows large signal peaks to be accommodated without compromising audio quality. With the E90, line array systems using 16Ω boxes can have up to eight boxes running from one side of a single amp. Production supply companies and audio-system installers are attracted by the smaller size, lighter weight and relatively lower costs.

BEEFCAKE

In keeping with the muscle amp theme, the E90 looks tough and feels strong. The vented front panel is metallic blue and sticks out from the body of the amp allowing access to the removable air filters that slide out for cleaning. There’s a cutout section in the centre enabling access to the volume knobs and power switch, as well as LED indicators for power on, audio-protect and channel link. A five-segment level/limit bar display for each channel has three green LEDs for –24dB, –12dB and –6dB, a yellow segment for –3dB and an orange segment to indicate that the limiter is working.

The vented rear panel has XLR inputs and links, a channel link button and Speakon output connectors. Each channel has a Power Reduction Circuit (PRC) facility that is controlled by two buttons used in different combinations to lower the output power level by 2, 4 or 6dB. The channel link PRC buttons have been thoughtfully recessed to prevent accidental operation and there are LEDS on the front panel to indicate the PRC is engaged. Mounting front and rear is recommended; the front rack ears are integrated, the rear mounting brackets are supplied but not fitted.

Power comes from a Class-D design that has been engineered for efficiency and high sound quality. The switch-mode power supply maintains a large power reservoir to enable high peak power without bass sag while the power control circuits manage mains input and amplifier output currents. Built-in low-distortion limiters combined with DC, thermal and short-circuit protection keep speakers out of harm’s way, which is important since the amps may be doing the job once performed by several, so reliability is vital. The specs are very impressive: noise and THD are low, the frequency response is flat to within 0.5dB and the power figures look like they’ve had an extra zero added to them; 2150W RMS per channel into 8Ω, 4500W into 4Ω and 8000W into 2Ω!

Equally impressive is their audio ability in use. The only meaningful way I could test the E90 was to connect it to the mids and subs of an installed PA that currently uses two amps for the mids and another two for the subs. In each case the E90 provided significantly more power than the two ‘normal’ amps, seemingly without raising a sweat. The mid boxes were clearer and punchier while the subs sounded like completely different boxes with more solid low frequencies, improved definition and a sense they could produce lots more level if required.

The E90 is not a cheap amp but if it replaces at least four conventional amps, saves weight and size for transport and improves the sound quality, it’s certainly good value for money. That value might only be fully appreciated by suppliers and users of big sound systems but there’s also a benefit to audiences from the superior sound quality made possible by these more powerful amps. The development of amps like the E90 also allows speaker designers and manufacturers to create new products that require more power, safe in the knowledge there are amps out there that will accommodate them. Muscle amps rule, okay?