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BMW 3-Series (E90 E92) Forum
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Help, annoying "Hiss" after amp upgrade
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09-06-2008, 10:34 AM | #45 | |
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09-06-2008, 05:25 PM | #49 |
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09-06-2008, 05:36 PM | #50 |
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no, i havent try it, i need to get some RCA cables
i have the Amp Interface Adapter laying around so im going to use it oem amp --> amp interface adapter --> line driver --> alpine amp hope it will works |
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09-06-2008, 07:47 PM | #51 | |
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My hiss issue is different from yours then my hiss comes from HU, using line driver could lift S/N, thus eliminates the white noise. |
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09-06-2008, 09:52 PM | #52 |
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Using the low level inputs instead of the high level in this amp could definitely prove if the amp itself is the problem, or it was "hissy" high level inputs.
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09-07-2008, 04:41 PM | #53 | |
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do you know a simple way to make an amp like PDX with differential balance input only to accept RCA input from a line driver or a alpine CDA HU? |
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09-07-2008, 06:06 PM | #54 |
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The great thing about balanced input amps is that it takes non-balanced inputs as well. It is the other way around (non-balanced inputs amps accepting balanced inputs) that can't...
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11-01-2008, 10:12 PM | #57 |
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There is a very noticeable "hiss" in a PDX 4-100 that I just installed, even without any inputs. In my case, it is the amp that most probably is bad as a PDX 4.150 that I also have does not have any hiss at all with the same power/ground/RCA/speaker connections.
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11-06-2008, 05:07 PM | #58 | |
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Hearing about these hiss struggles makes me appreciate my old alpine amps that are dead silent. I just took it as a given. |
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11-07-2008, 07:44 AM | #59 | |
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There are still a couple of things that I can do to try to further minimize the hiss to acceptable levels, with better cables, shorter grounds and speaker wires, and better layout of all the components. I will not be able to completely eliminate the hiss as I'm using the Cleansweep remote volume at 75%, so I can use the OEM volume controls but that's acceptable for me. |
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03-02-2009, 10:24 AM | #61 |
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I have spent months installing an Alpine system in my BMW 325ci. Being a convertible, everything required customized fitting and a tight squeeze for all wiring, fun, sort of... This included the amplifier, so I was very happy when I found the Alpine PDX-4.100...fit PERFECTLY in the factory CD changer fitting in the trunk.
So problem 1...I had the same problem with Channel 2 on the amplifier...terrible noise, above any regular level of system hiss. Amp ground is alright, still present with RCAs detatched. Realized it was the amp when I switched the outputs for channel 1 and channel 2, and the noise switched from right side to left side speakers. Alpine suggested I switch out the amp for a new one. Problem 2...second amp solved the channel 2 problem, but now I have low level noise in all channels. With the volume high you cannot notice the noise, but not all songs are naturally loud, and any break in a song makes this noise apparent. Alpine suggested that the amp is broken and I should return for another...seriously?! I am going to try amp #3, purchased from Crutchfield with a full, 30-day return policy. If the problem persists, I am going to switch to a new brand. I am not, as of now, satisfied with the quality of Alpine amplifiers. Update: I saw a few posts on here about Line Drivers. Would a line driver from the Alpine CDA-X100 HU to my PDX-4.100 solve this issue?? Thanks for your help! |
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03-02-2009, 10:52 AM | #62 | |
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03-02-2009, 11:01 AM | #63 |
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Yes, Alpine HU connected via patch cables directly to the amplifier. They are routed on the left side of the vehicle (all low gauge, red power wires are on the right side of the car). Noise is still present even with the patch cables unplugged. And in testing, I routed the patch cables essentially OUTSIDE of the car to ensure they were not the problem, picking up signal noise running inside the car. Technic, you seem very knowledgeable about system setups and have had experience with the PDX-4.100, any ideas? Could you explain a little more about the Line Driver? I could always install one and see if it works, Crutchfield is amazing with its 30-day trial/return period. Thanks!
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03-02-2009, 11:06 AM | #64 | |
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A line driver cannot be used to eliminate that kind of noise. You need to find the source of that noise first. |
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03-02-2009, 11:11 AM | #65 |
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Ground point is right next to the amplifier, back left portion of trunk. It is grounded to a specific BMW grounding point, brown wire BMW multi-ground is grounded here as well. I have seen SO many posts online about this specific amplifier and this problem. I find it hard to believe it is the product. One of my ideas is that this amplifier rests right below the BMW AM/FM antenna module. I have previously rule this out though since I did not connect the antenna turn on lead to my HU as I only use Sirius.
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03-02-2009, 11:14 AM | #66 | |
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