ppage27

Hello,

I have a C6 that I installed a sub and amp in the back cubbyholes.

AMP: Rockford Fosgate R500X1D Prime 1-Channel Class D Amplifier
Sub: Rockford Fosgate P3SD2-10 Punch wired at 4Ohm ~300W

I am pretty sure the the source of the interference is the amp but cant figure out how to prevent it. This is only observed when the radio signal is weaker. When I am home the radio will cut out and drop the signal. When I am closer to the radio tower the signal is strong enough not to be interfered with from the amp. If I turn power off to the amp when I am home the radio signal comes across nice and clear.

I have tried relocating the amp with marginal improvements. I have tried different grounding locations for the amp with no impact. Has anyone had the same issue and changed amps with positive results? I am in the DFW area and would be grateful if I could try other amps to see if the problem goes away. Car Toys wanted to charge 80$ an hr to swap my amp with theirs and drive to a spot where I could duplicate my interference issue. I laughed and thanked them for wasting an hours drive and an hour of my time waiting.

COMMANDER2OOO

I just completed my custom build with all JL Audio and I have the same problem, the radio signal is crappy now so I listen to other source like cd or xm. Sorry op I know this doesn't help much but I don't think its the brand.

daverulz

This is not an uncommon problem for class D amps. The power supplies throw out a ton of EMI that can mess with your radio reception depending on the frequency. If relocation didn't solve the problem, the only other options are to try a different class D amp that MIGHT not produce as much EMI (crapshoot) or to go to a class A/B amp.

A 2 channel amp A/B that does 300 watts bridged into 4 ohms should be pretty easy to come by for close to the price you paid for the Mono Rockford, but chances are it will be slightly larger.

If you want to stay with the brand, it looks like this is your best option:
http://www.sonicelectronix.com/item_...ch-P300X2.html
It's cheaper on amazon and ebay

I would buy from a source where you can easily return it. Amps can easily be hooked up and tested without causing any damage so if it doesn't solve your problem you could send it back.

I'd be pretty confident in this solving your issue. Best bet without spending any money is to find someone with a class A/B amp you can try in your home town.

ppage27

Thanks! I think thats kind of the conclusion I have ran into but was hoping I would be able to maybe shield the amp from the antennas. I wish I had worked with amazon sooner but I ended up just leaving it all disconnected.... No way I will be able to exchange I bet.

daverulz

No problem! It shouldn't be too hard to find a buyer for that mono amp without taking too huge a loss if it is still in good shape.

Curt D

I dumped my JL HD900/5 class D (nobody told me) for Mosconi a/b amps. I had zero reception with the JL. But ya, most Class D amps cause this.

ppage27

An update: I went ahead and purchased the A/B amp and got it installed. It is an improvement but there is still interference. I can now hear the radio at all points of my drive compared to it completely getting cut out but I still cant manage to consistently keep the "HD signal". I think I may try relocating this amp as well and also installing a switch in the cabin to turn on and off the amp. Having to get an allen wrench out all the time to remove the turn on wire gets way to repetitive.

Can you think of any material I can try to shield the amp from the antennas?

vetten76

Mine is terrible too. I have an Alpine HU. I even tried installing an amplified antenna in the roof halo area. Made no difference. I gave up. Is what it is. Why is stock so much better?

daverulz

What amp did you replace it with? A class A/B amp should not be introducing any FM interference.

ppage27

Went with a Rockford Fosgate Punch P300X2 - 300W RMS Punch Series 2-Channel Stereo Class AB Car Power Amplifier (P300X.2)

I will try the grounding location near the passenger seat again but I am doubtful. Using the new amp was marginally helpful. I can create a video of the set up if that's helpful. Does anyone know what wires power the antenna? I been wanting to double check that the voltage supplied to them doesn't dip when the amp is turned on.