Radio static since amp/sub install

[TPLSM3]

Looking for some help with my radio. I just installed a 10" JL W6 sub with a JL 500/1 amp. Installed the convertor off the factory sub wires in the back by the factory amp. When the JL amp is turned on, I get radio static that comes & goes (on FM, haven't checked AM). I've checked the grounds & they seem good, no other issues other than the static when the JL amp is on. It's not constant static either, it comes & goes. Any tips? I've searched on bimmerpost but have not found any pointers. By the way, I have the standard US stereo system, NON-premium.

[Technic]

Originally Posted by TPLSM3

Looking for some help with my radio. I just installed a 10" JL W6 sub with a JL 500/1 amp. Installed the convertor off the factory sub wires in the back by the factory amp. When the JL amp is turned on, I get radio static that comes & goes (on FM, haven't checked AM). I've checked the grounds & they seem good, no other issues other than the static when the JL amp is on. It's not constant static either, it comes & goes. Any tips? I've searched on bimmerpost but have not found any pointers. By the way, I have the standard US stereo system, NON-premium.

Are you using the signal sensing on that JL Audio amp?

FYI: The JL amp can accept high input voltages up to 8V, so you could either use the OEM HU/iDrive rear outputs as the inputs to the JL amp directly (highly recommended) or use the sub outputs of the OEM amp as inputs directly (last resort) without the need of any external LOC.

[TPLSM3]

I did not know I could use the JL amp directly to the outputs. Thanks for the info! I actually ended up getting rid of the static. Tightened up ALL the connections again & even though all seemed tight, the static is now gone. Now I can just enjoy the added bass. Thanks for your help though.

[gIzzE]

Is it a Class D amp??

They are well known for killing FM reception.

[gIzzE]

Yeah the amp is a ClassD, this is why it is ruining your radio reception.

I don't know who the hell thought using ClassD amps for cars was a good idea!!!??
The harmonics and noise generated from them enter the FM frequency range, so if you like listening to your radio I would seriously avoid using any type of Class D amp.

There have been a few problems with the official BMW Alpine upgrade and reception, the Blaupunkt plug and play range are the same, best to use a nice Class AB design imho.

[Technic]

I don't have any reception, noise or static anywhere with either of my two PDX amps in my M3...

It sounds to me -pun intended- that those examples (the OEM Alpine and the Blaupunkt) could be either a wiring or an installation location issue as the OP found out.

[gIzzE]

Yeah it is wiring dependant, you have to make sure that you run the cables as far away as possible with the existing cars wiring, and try and keep the amp as far away as possible from the cars antenna amplifier.
I can guarantee if the OP replaced the Class D amp with a Class AB amp his issues with FM reception would disappear.

It also depends where you live on how much you will notice the problem, if you are in the middle of a city with really strong reception you will be fine, but live somewhere between two masts where reception is not as strong and you can have real problems.



This explains the Class D issue......

http://www.mtx.com/caraudio/technology/ampClassD.cfm

[NYC6]

Originally Posted by gIzzE

Yeah the amp is a ClassD, this is why it is ruining your radio reception.

I don't know who the hell thought using ClassD amps for cars was a good idea!!!??
The harmonics and noise generated from them enter the FM frequency range, so if you like listening to your radio I would seriously avoid using any type of Class D amp.

There have been a few problems with the official BMW Alpine upgrade and reception, the Blaupunkt plug and play range are the same, best to use a nice Class AB design imho.

Had the same issue with my Vette. JL 500/5 installed. Reception was murdered in both AM/FM. The installer told me its fine and normal, I was . Called JL in Miami and one of their lead guys told me. Sometimes(depending on where you live) reception can be adversley affected by Class D amps. Made the shop remove the 500/5, got my money back and went to a different shop and they installed a JL 450/4v2 and a 300/2v2(Stealthbox amp). That solved the problem.

[gIzzE]

Class D is not even a nice sound, OK for sub duties, but they sound pretty hard compared with a nice Class AB amp of the same price.