View Single Post
      08-18-2012, 11:03 AM   #14
Private First Class
ibo's Avatar

Drives: '09 BSM 335xi e90 LCI M-Sport
Join Date: Jun 2009
Location: Norcal

iTrader: (2)

Originally Posted by dmatre View Post
Is your hiss bad enough to hear it if the car's running? Or are you checking it with the car powered up but not running?
I'm doing the latter, which makes any sort of hiss much more apparent. Like you said, when the car is running, with engine and road noise, the hissing pretty much gets drowned out. But with the ignition off, it's a slap in the face

Originally Posted by Technic View Post
If according to you there was a "QUIET, QUIET" hiss when the OEM amp was plugged in then you will have an increase of such hiss when a more powerful aftermarket amp is plugged in if the chassis ground is used. That is what you are having now, apparently.

My suggestion is to remove the OEM HU, unplug the Quadralock in the back, and take a close look at pin 12 (ground). Make sure that the radio pins and the Quadralock pins are having a solid contact without any wiggling.
Thanks for chiming in. I was worried I'd have to remove the HU. Sigh...I guess I'll have to tackle that when I have the time, just to be completely sure. How hard is this to do?
COBB Stage 2+ | Alpina B3 TCU Flash | ER FMIC & CP | Tial Q | Injen CAI | VRSF DP | BMS OCC | KW V3 | M3 Rear SFB / Sway Bar / Susp Bits / Strut Brace | Megan Racing Toe Arms | HPA Swaybar Endlinks | Apex EC-7 | Michelin PSS | MH 75mm Stud Conv | OEM Perf Grills and Diffuser | Exotics Tuning Front Lip | LUX H8 | Luminics Krypton JDM Yellow | LLumar 35%