Alpine MRV-1507
www.alpine1.com

With a stylized design and solid performance, Alpine’s latest class AB amp offers big power.

The MRV-1507 is a two-channel amplifier with power ratings of 225 watts x 2 or 900 watts x 1 into 4-ohm loads and 450 watts x 2 into 2-ohm loads. Features include an internal crossover and subsonic filter, line level outputs, fan-forced cooling, and a low frequency EQ with full parametric operation.

Performance
I’ll give it to you straight — the advent of class D amplifiers limited the number of applications where a class A/B amp of this size makes a lot of sense. An automotive charging system is not a great power supply, so if you want lots of amplifier output, you’d better do the most with what you’ve got. Our lab power supply is far superior to an alternator and battery. The increased efficiency of a class D goes a long way toward actually making a kilowatt in real life.
However, if you have your heart set on a great big class A/B, you’d be hard pressed to find one that performs better overall than the MRV-1507. I’ve seen a whole lot of class A/B’s in this power range over the past few years and have come to dread them. They’re usually the biggest of pains to deal with and are often frighteningly unstable. Anything that draws 140 amps and hums like a high voltage transformer is bound to cause some apprehension. There are times when one feels led to probe the limits carefully, lest the magic smoke should appear.

By comparison, the MRV-1507 ran with no more fuss than a good amp half it’s size. Of course, it has a much larger appetite than a 100-watt x 2 unit, but it’s very well behaved and produces impressive performance specs. Signal-to-noise of 118 dB and 36 percent efficiency at 1/3 power are pretty rare numbers, especially in a kilowatt amp. If I had to poke a finger at one spec, it would be the 22 dB SPL turn-off noise. While this should only be considered overly loud in comparison to the -3.7 dB SPL turn-on noise, an SQ judge might knock off points in a competition.

Connections & Adjustments
The MVR-1507’s chassis is laid out with power connections on one end and input/output connections and configuration switches at the other. All of the units variable controls are located on top of the heat sink with a protective cover. Connections to the amp include RCA inputs, RCA line level outputs, and 1/2-inch spade receptacles for all power and speaker connections. The amp has an extra B+ connection, which can be used to bypass the internal fuse and line choke. Switched adjustments include input mode, phase invert, crossover enable, and parametric EQ enable. Variable adjustments include input sensitivity, high pass cutoff frequency (30 Hz to 200 Hz), low pass cutoff frequency (30 Hz to 200Hz), and the parametric EQ controls, which include center frequency (30 Hz to 200 Hz), Q factor (1 to 10) and boost/cut (+/-12 dB), and a fixed subsonic filter.

Installation
A parametric bass EQ? Hello, now you’ve really got my attention. Simple bass boost is one of the most useless features in car audio. It wasn’t designed to fix problems; rather, the idea was to give the customer more of what they already had (bass). If you don’t know any better, or are primarily concerned with being obnoxiously loud, that might sound like a good idea. However, if you’re looking for SQ and do know better, then an arrangement such as the one found here will be much more likely to satisfy. The ability to cut rather than boost is particularly helpful. You can actually smooth a lump in response with a little bit of cut, but all the boost in the world will never correct a destructive resonance. Try removing what you don’t want rather than boosting what you do — it really works. (Alpine reports that this is part of the company’s BassEngine system concept — it allows users to maximize the sound quality and impact of bass reproduction in any vehicle.)

At about 2.4 x 10.3 x 21 inches, and about 19 pounds, the MRV-1507 definitely won’t fall into the small amp category. However, it appears to have a decent heat sink design in addition to fan-forced cooling. All controls are either recessed or otherwise protected and, well, it’s just a good looking amp. The subdued matte gray and brushed aluminum finish indicates that there are a few companies in mobile audio that have retained some measure of class. There’s more than enough room on the top of the MRV-1507 for one of those 1500-watt MAX POWER blurbs, but Alpine didn’t go that route. I guess tacky amps aren’t in their repertoire.