A 140 amp alt will still dim, especially if you're doing 1300W. It puts out plenty of power, but the system is slow in response. I just installed a 140 amp alternator, I have an Optima Red top, and My Directed 400D Running @ 4 ohms is still (ever so slighly) dimming my lights slightly on peaky hits at high volume. Hell my High speed fan dims them for a second, before the regulator corrects.
A trip with the multimeter might show you what'* going on. Check between battery, cap, amp. Also check to see if the amplifier is going into a protection mode.
'06 Vee Dub GTI 2 door Tornado Red
- 2.0 Turbocharged, Intercooled, Direct Injected, 6 Speed DSG, Underbody Aero, 17" Classix
- Moonroof, Bi-Xenon headlamps, Interlagos Plaid Sport Seats, 6 Disc In-dash, iPod integration, GTI Monster Mats (winter)
'93 Bonneville SE Purple Pearl H4U package - picked up June 23, 2003, Traded-in June 28, 2007...