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I have fitted 2 x 10" Rockford fosgate subs with a Rockford fosgate mono block amp in to my C180 w205. I have taken the wires from the sub on the passengers floor to the amplifier (the Rockford amp uses speaker cables to turn on amp and in place of RCA's) however the amp keeps going in to protection mod when I turn it up. I have test wiring, connection, voltage everything I can think of and it still does it. Has anyone else had a similar problem? Oh I have also tried it with 2 different amps and same problem. Also there are no shorts and at 2 OHMS
Last edited by Docharding; 03-12-2016 at 04:49 AM.
Well it's either the cables overheating or the amp that will be putting it into protection mode.
That or the amps aren't matched to the speakers and it's overdriving them.
OK so I tested it from my other cars radio, I pulled the radio out and ran the RCA's from one car to the other and the amp is not going in to protection mode. So I'm thinking it got to be some sort of problem with the factory radio. What is weird is the wires for the sub on the passenger floor (which I have used the channel for the amp) takes one wire from the front right channel and the other from the left rear channel, I'm wondering if there is a bridge in the radio for that to happen and because it is bridged it's sending to much voltage to the amplifier
Take it to a Pro-audio installer have your set-up corrected....before you blow something UP
The pro guys can't fix it either. They have tested everything and say it's perfect. I have been fitting my own and friends audio for 15 years so I'm pretty good at it. The 2 installation places I have taken it to couldn't believe I did the install my self
The pro guys can't fix it either. They have tested everything and say it's perfect. I have been fitting my own and friends audio for 15 years so I'm pretty good at it. The 2 installation places I have taken it to couldn't believe I did the install my self
your custom work is very cool, but the audio tech is always changing and MB tries to make it very difficult for a diy or semi-pro to upgrade the audio system in any way... good luck on your quest to upgrade your oem audio.
Everything below is assuming that you are using the factory head unit and have not replaced it with an aftermarket HU.
I'm assuming you already checked the specs for the signal output from the factory head unit right?
Does your amp immediately go into protection mode, or does this happen as you increase volume?
Is the factory HU working as a pre-amp? Have you added a separate signal crossover?
Have you measured power output from the crossover and/or HU to the amp?
Have you measured power output from the amp to the subs?
Ford was notorious for problems like this when aftermarket subs were added to the factory HU. The resistance and voltage of the stock components were different from aftermarket standard. It would cause the aftermarket sub to pop and crackle on powering up.
I think something similar might be going on here. Basic OEM systems sometimes have weird designs for signal filtering. That is where I would begin troubleshooting.
Thanks everyone for your input and ideas. Rockford fosgate has got in contact with me and they say all I need to do is disconnect the negative from the RCA's and only use the positive. The amp will use its own internal earth. I will test it tonight and share my findings
03-12-2016, 04:46 AM
