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I have a JL Audio XD800/8v2 amp that is hissing on a 2013 230. It starts when the linc screen boots up. This amp as well as the other amps are all grounded to the same place and powered at the same location. None of the other amps hiss. Any ideas to remove the hiss?
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Which speakers are you driving with the eight channel amplifier?
What other amplifiers are you running and what speakers are they driving? -
Clarion Head Unit CMD7
6 Polk MM6501 in boat speakers
1 10" Polk sub located behind drivers seat side panel mount
4 Roswell 7.0 airborne Heads 200w rms
Polk D4000 amp- Powering 4 cockpit speakers (factory Polk Momo)
Polk D5000 amp- Powering 2 bow speakers and sub (factory Polk Momo)
JL Audio XD800/8V2- 4 Roswell 7.0 airborne Heads (bridged to 4 channels)
Kicker line drivers hooked up to the tower speakers and to the sub.Comment
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You hear hiss from the tower amplifier because it is driving four small HLCDs with highly accentuated treble as compared to the in-boat speakers. An HLCD is way more sensitive on the order of 10 times power which translates to 10 times the hiss.
Because you need to be populating all eight amplifier inputs the available preamp voltage is divided causing you to raise the input gain. The line driver should compensate for this. Your amplifier input gains should be set to less than 50%.
The speakers are simply reproducing the noise they receive. The amplifier is simply amplifying the noise it receives.
Besides the amplifier input gain levels, you may need to concentrate on that upstream loop where the noise is being introduced.Comment
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Finally got some time to fiddle with the stereo.... Adjusted the gains etc (re-tuned) per the Earmark Audio method. Also, noticed that the battery switch made some difference. Had the most noise on battery 1, slightly less on battery 2, and the least when switched to both battery 1+2. I also get a little more feedback when the blower is on and get the most hum/hiss once the Linc system powers up. Any thoughts based on these findings?Comment
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Absolutely. It would appear that components of the audio system chain, and possibly the Linc system, are supplied by more than one battery.
You have either a supply or ground loop.
There can only be one B+ physical connection point. Only one ground physical connection point. No exceptions.Comment
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