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Noise Issue

5K views 13 replies 4 participants last post by  Shadow_419 
#1 ·
2002 Ford Lightning (Single cab F-150 pick up)
Alpine iLX-W650 Head Unit
Sky High Audio RCA’s (1) 9 ft, (3) 3 ft
Dayton Audio DSP-408
Audision VOCE AV 5.1k Amplifier
Focal 165 KRX2 (Running Active)
Stereo Integrity BM MK V 12” Sub
Installed the system last Saturday, turned on the system radio muted, no engine running, and the dreaded ground noise, whine hiss!
Amplifier ground is 0/1 gauge 1 ft. long, directly to the chassis of the truck, cleaned retightened the ground, ran a new 14 gauge ground to the head unit, still the same issue. Unplugged the RCA (Front Out from head unit) from the dsp input, same noise, unplugged the RCA’s to the amplifier inputs the noise is gone, the ground from the dsp is 16 gauge wire about 10” long, bolting directly to the amplifier ground. Could the dsp be causing the problem? Has anyone else experienced this problem the Dayton dsp, or am I overlooking something?
 
#4 ·
Might be the dsp but it could be the amplifier or the noise is getting picked up between the dsp and amp. Have you figured out which output channel you're getting the ground loop noise from? Or is it all the channels?
 
#6 ·
If you find that it's only one channel or pair of channels, try a cable swap. You could also try to run a grounding wire from the rca shield to a common ground point if you can isolate it to one channel. If the female rca plug ground is bad I'd look for a replacement from parts express.
 
#7 ·
Strange - you seem to be having the exact same issue as the person in this thread - the Dayton DSP-408 seems to be the source of the noise - once it's removed from the chain, things are dead quiet (scroll to last post for latest update):

New Kenwood Excelon System

While the noise seems to be coming from the DSP, the DSP itself doesn't seem to be "bad" (he's exchanged it for a new one already)...
 
#9 ·
I had problems setting the amplifier gains, I used the DD-1 turned the head unit up all the way (35) no distortion, then I turned the gains all the way up on all amplifier channels, and it registered no distortion, I thought that was unusual, I then used a Multimeter and turned Channel A (tweeter) all the way up and couldn't get to the calculated voltage, Channel B (Woofer) turned to the proper voltage, just fine, Channel C (Sub) turned the gain all the way up and didn't see the calculated voltage. So I left Channel B alone and turned Channels A and C to about 1/2 way.
 
#10 ·
Definitely wouldn't use dmm to set gain for tweeter channels. There literally is no way you'll use that many watts on your tweeter without burning the voice coil. As long as your tweeters are getting loud enough less gain is better. They're the most efficient speakers in your set up normally and the lower the noise floor the better.
Can you raise the output level of tweets and mids in dsp and lower amp gain?
 
#12 ·
It's like a fine balance. Every piece of equipment has a noise floor and you want to maximize signal with minimal noise. The less noise that makes it to the amplifier the better. Just be careful with the volume because you want to make sure the signal isn't clipping.
 
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