Amazon.com: MRX-M50 - Alpine Monoblock 500 Watt RMS Subwoofer Amplifier: Car Electronics. The manual says otherwise, but I can confirm that 4AWG works in this amp wonderfully and is much easier to install and have Download. Find great deals for Alpine MRX-M50 1-Channel Car Amp. Shop with confidence Manuals and User Guides for Alpine MRD-M500. We have 2 Alpine MRD-M500 manuals available for free PDF download: Owner's Manual.