Subs and speakers pulsating all of a sudden
05-05-2015, 04:41 PM
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Subs and speakers pulsating all of a sudden
So took the new boat out (2001 Checkmate 270) Sunday and everything was going well until we stopped after running hard and I noticed I had no music any more. The stereo had worked fine in my shop and for the couple hours we were in the river before hitting rough water out in a bay. Jumped in the cuddy and see I have no power on the HU. Flipped the switch on the dash a couple times and nothing, whatever not a big deal just left it off. Figured a wire came lose or it blew the fuse from bouncing around.
Pulled the HU and all the wiring was fine, still nothing. Pulled the power/ground, cleaned them off, and then pulled the face plate and snapped it back on. Head unit turned on after this. So I thought all was well. I was was wrong, flipped the switch to turn the amps on and now the speakers and subs just pulsate.
Head unit is wired directly to battery two with the ignition wire to a switch on the dash. The original stock 4 speakers are hooked up to this. This head unit is brand new, manufacture date of Feb 2015 on the chassis. No idea why it stopped working, sadly my guess is the faceplate wiggled loose.
Both amps are wired to battery two with the remotes split into a second switch on the dash that activates the amps which are hooked to four more speakers and two 12's. Amps power and ground are 4 gauge from the battery into 8 gauge after a distribution block. All equipment is Rockford other than the HU and stock speakers. Head Unit is a brand new pioneer 5xxx level.
I traced all the wires down to the stereo and I see no issues with it so my next step was new batteries thinking maybe it was a low voltage issue. The batteries are from 2004 and I wasn't running the motor during any of this. Batteries are now brand new group 29's, still popping.
So, I can run one RCA to one sub and it will play fine until I turn the volume all the way down, then it will pop and I can hear static or a hmmmm in the sub. Hooking the second sub RCA up leads to the pulsing. This is with the head unit powered up at the same time, without the head unit powered nothing happens.
Hook up any RCA's to amp two will result in everything pulsating, doesn't matter if the HU has power or not. I completely pulled the power wires to the HU and hooked up the RCA's to the speaker amp results in the popping/pulsating. They will play music but again turning the volume down to nothing results in a pop/hmmm/static sound. Doesn't matter if the RCA's are hooked to the HU or not, just plugging one in to the amp results in pulsating, the other ends just hanging.
I can see this being a ground loop problem but why all of a sudden? It worked fine and then it didn't. I can't find a pinched wire, I've tried various RCA cables to negate one being cut or grounded out.
Any advice? My next step is to order an RCA ground loop isolator. I just wanted to understand why this would happen out of no where. All grounds are clean and tight.
Pulled the HU and all the wiring was fine, still nothing. Pulled the power/ground, cleaned them off, and then pulled the face plate and snapped it back on. Head unit turned on after this. So I thought all was well. I was was wrong, flipped the switch to turn the amps on and now the speakers and subs just pulsate.
Head unit is wired directly to battery two with the ignition wire to a switch on the dash. The original stock 4 speakers are hooked up to this. This head unit is brand new, manufacture date of Feb 2015 on the chassis. No idea why it stopped working, sadly my guess is the faceplate wiggled loose.
Both amps are wired to battery two with the remotes split into a second switch on the dash that activates the amps which are hooked to four more speakers and two 12's. Amps power and ground are 4 gauge from the battery into 8 gauge after a distribution block. All equipment is Rockford other than the HU and stock speakers. Head Unit is a brand new pioneer 5xxx level.
I traced all the wires down to the stereo and I see no issues with it so my next step was new batteries thinking maybe it was a low voltage issue. The batteries are from 2004 and I wasn't running the motor during any of this. Batteries are now brand new group 29's, still popping.
So, I can run one RCA to one sub and it will play fine until I turn the volume all the way down, then it will pop and I can hear static or a hmmmm in the sub. Hooking the second sub RCA up leads to the pulsing. This is with the head unit powered up at the same time, without the head unit powered nothing happens.
Hook up any RCA's to amp two will result in everything pulsating, doesn't matter if the HU has power or not. I completely pulled the power wires to the HU and hooked up the RCA's to the speaker amp results in the popping/pulsating. They will play music but again turning the volume down to nothing results in a pop/hmmm/static sound. Doesn't matter if the RCA's are hooked to the HU or not, just plugging one in to the amp results in pulsating, the other ends just hanging.
I can see this being a ground loop problem but why all of a sudden? It worked fine and then it didn't. I can't find a pinched wire, I've tried various RCA cables to negate one being cut or grounded out.
Any advice? My next step is to order an RCA ground loop isolator. I just wanted to understand why this would happen out of no where. All grounds are clean and tight.
05-05-2015, 05:45 PM
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If you have an RCA to a 3.5mm headphone cable try connecting it to an outside source like an iPod or something like that. Did you check you battery connections to the amps and batteries? You also should look at all the common places that your speaker wires travel, maybe something crushed a bundle of them. The pulsating is usually a bad speaker or sub, but for that to happen on both amps means that the head unit might to toast. Will the HU play the original speakers without the amps connected?
05-05-2015, 05:59 PM
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I don't have a 3.5 to RCA but I can pick one up to try it they're cheap.
Yes, it plays the original speakers just fine. I didn't know if the preamp out could've went bad. I never did know why it shut off but I could hear it banging pretty good in the dash, it definitely needs more support than it has now before heading out again.
Yes, it plays the original speakers just fine. I didn't know if the preamp out could've went bad. I never did know why it shut off but I could hear it banging pretty good in the dash, it definitely needs more support than it has now before heading out again.
05-05-2015, 10:33 PM
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Swung by Walmart and picked up a 3.5 to RCA converter. Already had a RCA splitter and hooked everything up to my tablet, it plays fine through the tablet. Something must have went wrong in the Preamp outs at some point on the HU.
05-06-2015, 01:04 PM
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If the outside of the RCA cable plug touches metal or a ground it can cause that. It's a square wave that's being produced. It sounds like you may have it isolated already.
Keep us posted.
Keep us posted.
