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      08-17-2012, 08:28 PM   #1
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Drives: '09 BSM 335xi e90 LCI M-Sport
Join Date: Jun 2009
Location: Norcal

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Noticeable static/hiss in tweeters after amp install

Hey all, I could def. use some help here. Searched but nothing helps so far. I recently upgraded to VP's HIFI upgrade. Upon concluding the install, I noticed a subtle but noticeable hiss (white noise?) coming from the tweeters. The level of hiss does not increase with volume.

Here are the steps I took to troubleshoot the issue.

1. Change ground location from rear fender well to battery/chassis ground behind the rear bumper plastic trim.

- No change.

2. Adjust gain on amp (first tried ARC mini and then tried JL XD600/6).

- Hiss increases and decreases with gain adjustment but even at minimum gain, the hiss is still noticeable.

3. Unplug RCA plugs.

- Hiss is gone.

4. Plug in ipod with RCA adapter.

- Hiss is not present, bliss.

5. Changed the ARC mini back to stock HIFI amp.

- Hiss is gone. I have to point out that even before the upgrade, I could hear a very VERY quiet hiss through stock amp/tweeter if I put my ear one inch from the tweeter. I've always just thought that this was normal. With new speakers and stock amp, the same QUIET QUIET hiss is there, which is significantly more quiet than the new ARC mini.

At this point, I've troubleshooted with VP plenty of times via phone and he graciously sent me a JL XD600/6 with new harness to test with.

6. Replaced amp with new JL XD600/6.

- Same hiss as with the ARC mini amp.

At this point I'm kind of stumped. I can use any help or suggestions that yall may supply. I'm starting to wonder if my head unit is crazy noisy and I've read somewhere online about audio vs chassis ground which confused me quite a bit. Any pointers will be appreciated. Thanks guys!
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