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Old 06-18-2017, 08:17 PM   #1
tsouzee
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Default Background hissing noise with Alpine Powerpack....Any ideas?

On Friday I wired up an Alpine PowerPack with plans to run it to the glove box. I have a 7" Starlink non HK head unit.

I used a breakout harness to wire it up, and soldered on male RCA's to the speaker wire so I can plug them right into the amp's female RCA's and not have to cut them off. Power, ground etc were all run through the harness. I also let the 'high level' speaker inputs assist with the remote turn on of the amp.

Once I put the car in accessory I heard an audible hiss in the background. I powered the HU off but the sound was still there coming through the speakers. Not as noticeable with the car on but definitely noticeable with the car in accessory. I had the amp's gain two bars from the minimum. The amp did help the speakers pump real nice, but even at higher volumes I can hear some background white noise that shouldn't be there. It's not terrible but I'm very particular.

Any ideas to remedy this? I've pulled the amp out for now. If I can get some remedy suggestions I'll give it one more go next weekend, and then may just return the amp.
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Old 06-19-2017, 11:58 AM   #2
noon
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Unfortunately my powerpack does the same thing. When you are amplifying the signal coming from the head unit, any noise that the head unit is outputting will be louder. Since these cars have a crappy head unit it's not surprising that they output a little white noise.

I too was a little annoyed by it at first, but after a few months with the power pack I don't notice it at all anymore. I rarely sit in my car in ACC mode with the radio off. As long as you don't set the gain too high turning on your engine will drown out that hum as well as if you actually play any music, but I could see why it would be annoying.

If you really want to get rid of the hum while still using the power pack then you will need to get a new sound source, aka a new head unit that will output a cleaner signal. It also sounds like others have had success using external signal processers, like the miniDSP, to clean up that signal.
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Old 06-19-2017, 12:11 PM   #3
tsouzee
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Thanks man. Really appreciate. Got your PM too! The amp did help but definitely a synthetic and noticeable aftermarket sound to it. Not sure what to do. I may try to hook it up again and really play with the settings to see if I can get it to where I like it, or just leave it stock.
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Old 06-19-2017, 12:19 PM   #4
noon
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I think where the powerpack shines is that it allows you to reach a higher volume level without the sound distorting, and at lower levels I think it helps the bass hit a little harder.

For the cost I definitely think it's worth the improvement it gives, but if you're after higher fidelity sound then you may need to invest more into your system to upgrade the head unit and the speakers themselves.
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Old 06-19-2017, 02:12 PM   #5
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If you hear the hiss with the HU off, the HU is not the source. The noise might be picked up from the harness. Shielding cables or twisting wires might reduce capacitance.

Quote:
Originally Posted by tsouzee View Post
Once I put the car in accessory I heard an audible hiss in the background. I powered the HU off but the sound was still there coming through the speakers. Not as noticeable with the car on but definitely noticeable with the car in accessory. I had the amp's gain two bars from the minimum. The amp did help the speakers pump real nice, but even at higher volumes I can hear some background white noise that shouldn't be there. It's not terrible but I'm very particular.
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Old 06-19-2017, 06:30 PM   #6
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Quote:
Originally Posted by CRAZYHAWK View Post
If you hear the hiss with the HU off, the HU is not the source. The noise might be picked up from the harness. Shielding cables or twisting wires might reduce capacitance.
I wonder what would happen if the amp was feed with his own power cable and a proper ground

Quote:
Originally Posted by noon View Post
Unfortunately my powerpack does the same thing. When you are amplifying the signal coming from the head unit, any noise that the head unit is outputting will be louder. Since these cars have a crappy head unit it's not surprising that they output a little white noise.
I'm with the 6.2, worse pos than the 7.0" and I have no noise issue (*) and the gain are set to almost max. Kenwood KAC-m3004.
(*) Except a strange one related with the dimmer
No dimmer, no noise.
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Old 06-19-2017, 07:42 PM   #7
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Quote:
Originally Posted by BHOD View Post
I wonder what would happen if the amp was feed with his own power cable and a proper ground :
This would be a good start.
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