Wehan Posted September 29, 2015 Author Report Share Posted September 29, 2015 Op if you can try making a test bench to test the amp on. That will completely rule out whether it's the amp or not. Best thing to do is to start at one end and work your way to the other. I can do this, however if I just power the stereo without the engine running the noise is gone. What would a test bench rule out that this doesn't? Link to comment Share on other sites More sharing options...
Wehan Posted September 30, 2015 Author Report Share Posted September 30, 2015 Ok, so I went out to the car just now thinking I would, with the car running, head unit on shifter and rca's removed from the dash start to pull out my rca cables to see if the wine stopped or got worse as I moved them around. I went out, started the car and stuck my ear in front of my front passenger tweeter and hear silence (other than a floor noise hiss) WTF? Go around to the drivers side and the wine is there!! I can't tell if it's in the rear speakers as I can't get my head between the rear deck and the glass to listen close enough. ANYWAYS I shuffle around my passive crossovers and no change, flick the tweeter attenuation switch from 0 to +3db and it gets louder, switch it down to -3db and it gets quieter. Go to the parts box and grab a run of speaker wire and run it from the amp to the crossover over the seats, wine still there. Disconnect the input on the crossover and it's gone, Swap front left/right rca cables at the amp (system powered down) and the wine is now in BOTH front tweeters... Swap the rca back and it is still in both. Other than this I touched nothing. Link to comment Share on other sites More sharing options...
SIDE SHOW Posted September 30, 2015 Report Share Posted September 30, 2015 try different set of rca's? Link to comment Share on other sites More sharing options...
Wehan Posted October 1, 2015 Author Report Share Posted October 1, 2015 try different set of rca's? Im on the 3rd set of rca cables now, first set was scoche walmart junk, 2nd was a nice set of Knu Karma ss and now I have the Soundrive HF cables. Pulled the amp today and getting ready to ship it back to Crescendo to be checked out, even they said something must be up with it when I told them everything I had tried and the cables I had. Link to comment Share on other sites More sharing options...
Wehan Posted October 5, 2015 Author Report Share Posted October 5, 2015 Had alternator tested, came back OK, disconnected the alternator plug to disable alternator and the whine is still there (this also disproves my AC ripple theory as the ripple was .013 milivolts with alternator disabled and that is well within acceptable range), I even set my head unit on the shifter, routed the RCA cables out the door, out into the lawn, back in the door and directly to my amp and still had whine!!! Only way it goes away is if I disconnect the RCA cables at one end or the other. I pulled the Crescendo and stuck a little MTX in its place and that has identical whine so I know its not the Crescendo. If my amp ground is bad wouldn't it whine without the rca's hooked up? Link to comment Share on other sites More sharing options...
SIDE SHOW Posted October 6, 2015 Report Share Posted October 6, 2015 So it only whines when you have 4 rca's going into it from the headunit? and doesn't whine when your have 2 rca's going into it? try an ipod straight into the amp and use splitters to make sure you use all 4 rca inputs goinginto the amp, I think the noise will be gone. i'm guessing a deck issue, try running a separate pwr and ground for the deck Link to comment Share on other sites More sharing options...
Wehan Posted October 6, 2015 Author Report Share Posted October 6, 2015 So it only whines when you have 4 rca's going into it from the headunit? and doesn't whine when your have 2 rca's going into it? try an ipod straight into the amp and use splitters to make sure you use all 4 rca inputs goinginto the amp, I think the noise will be gone. pico fuse maybe Whines with 1,2,3,and/or 4 rca's in it, did the mp3 into 2 and whine was still there. Link to comment Share on other sites More sharing options...
SIDE SHOW Posted October 6, 2015 Report Share Posted October 6, 2015 try take the headunit out the car and run pwr and ground straight from the battery to the headunit. seems that model amp always has noise issues too Link to comment Share on other sites More sharing options...
Wehan Posted October 6, 2015 Author Report Share Posted October 6, 2015 try take the headunit out the car and run pwr and ground straight from the battery to the headunit. seems that model amp always has noise issues too I'll try this tomorrow after work and post back. The Crescendo and another amp have identical noise issues, the other amp I have used in several other vehicles with no problems so I know it is good. Link to comment Share on other sites More sharing options...
SIDE SHOW Posted October 6, 2015 Report Share Posted October 6, 2015 hope you sort it, Im hope it's just happening coz your picking up the pwr and ground from the same spot as the amp Link to comment Share on other sites More sharing options...
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