Coding base radio to HiFi - BMW 3-Series (E90 E92) Forum

delrioi · 03-25-2012, 05:39 PM

I have a base system with iDrive running a technic harness, ms-8 and alpine PDC-5 amp. I get a small hiss when the car is running or not, when I press the brake pedal it's gets louder. I thinks it's a ground problem somewhere. My question is if I code the radio to Hifi and use the RCA connections is there a chance the problem might be solved. Will the signal from the radio be cleaner? Or should I just worry about finding the grounding problem?

ctuna · 03-25-2012, 07:26 PM

Post pictures of your grounds.
Also post pictures of your amplifier wiring.
Measure your grounds for low resistance .
Lots of other people have a similar setup, They will probably chime in sooner or
later.

bmw325i · 03-25-2012, 08:43 PM

Its probably a ground problem. Ground to the battery, or where the battery is grounded to the car if possible.

VP Electricity · 03-25-2012, 09:53 PM

You mean PDX-5, don't you?

I think it's the amp. Hiss problems with that generation of PDX amps were a common complaint, and the PDX-5 is an older design. It's been complained about before.

How low are your amp input gains?

03-25-2012, 05:39 PM	#1
delrioi Enlisted Member Drives: 2013 135i Join Date: Aug 2010 Location: Minneapolis Posts: 44 iTrader: (0)	Coding base radio to HiFi I have a base system with iDrive running a technic harness, ms-8 and alpine PDC-5 amp. I get a small hiss when the car is running or not, when I press the brake pedal it's gets louder. I thinks it's a ground problem somewhere. My question is if I code the radio to Hifi and use the RCA connections is there a chance the problem might be solved. Will the signal from the radio be cleaner? Or should I just worry about finding the grounding problem?
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03-25-2012, 07:26 PM	#2
ctuna Colonel Drives: 325xi 06 wagon MT Join Date: Jan 2010 Location: Santa Cruz, Ca Posts: 2,743 iTrader: (0)	Post pictures of your grounds Post pictures of your grounds. Also post pictures of your amplifier wiring. Measure your grounds for low resistance . Lots of other people have a similar setup, They will probably chime in sooner or later.

03-25-2012, 09:53 PM	#4
VP Electricity Brigadier General Drives: 2007 E91 328 xi Join Date: Jan 2008 Location: portland oregon Posts: 3,089 iTrader: (3)	You mean PDX-5, don't you? I think it's the amp. Hiss problems with that generation of PDX amps were a common complaint, and the PDX-5 is an older design. It's been complained about before. How low are your amp input gains? __________________ musicar northwest portland or musicarnw.com BMW systems and subwoofers

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03-25-2012, 08:43 PM	#3
bmw325i Lieutenant Colonel Drives: 2006 BMW 325i Join Date: Oct 2010 Location: United States Posts: 1,667 iTrader: (4)	Its probably a ground problem. Ground to the battery, or where the battery is grounded to the car if possible.