Anyone ever had this?

[Ffej]

Install done, sounded perfect for about a month, then all of the sudden I have engine whine through front door speakers AND I started getting an amp thump during power up AND power down. Never had either of these before, and they started at the same time. Any ideas?

Thanks

Head unit - Kenwood DPX592BT

Front channel - Alpine SPR-68 w/ CT-Sounds AT-125.2

Rear channel factory speakers run by head unit

Subs - pair of SA-12 D2 rev.3 w/ Alpine MRX-M110

Click to read more...

 

[jatyro91]

As always, check your ground.

 

[JohnKuthe]

As always, check your ground.

Yep, those grounds can be weird! I had one to the chassis that tested at very low resistance when continuity/resistance checked against a 4AWG jumper cable clamped well to the neg battery post, so I had my installer guy install a 0AWG ground cable to the neg battery post and run it all the way to a distribution block to run 4AWG grounds to my two amps! Cured the weird unloaded V9 amp heating I was getting while my amps were grounded to that chassis ground we'd chosen!

John Kuthe...

 

[Flipper245]

And if your grounds are bad, the Amps may try to ground themselves out through your rca's and damage your head unit which will cause alt noise. You should always disconnect your rca's before messing with your power or ground cables. Especially don't hook up your power wire without the ground hooked up while your rca's are hooked up.

 

[JohnKuthe]

And if your grounds are bad, the Amps may try to ground themselves out through your rca's and damage your head unit which will cause alt noise. You should always disconnect your rca's before messing with your power or ground cables. Especially don't hook up your power wire without the ground hooked up while your rca's are hooked up.

Good idea, I'd never thought of that as me and installer guy had my amps power and grounds run before the RCAs were even connected. Probably a good thing too, from what you just said.

John Kuthe...

 

[Ffej]

Update: I know why I'm getting the amp thump at power up and power down. One of my two amps is staying powered on, even with the head unit off. This wasn't happening until all of the problems started. My turn on lead goes to both amps, but for some reason the Alpine (sub amp) is not turning off. Could a ground be the problem? They also share a ground through a distribution block. Just found out that the top RCA input to the amp powers it on/off when plugged in and unplugged.

 

[Ffej]

And if your grounds are bad, the Amps may try to ground themselves out through your rca's and damage your head unit which will cause alt noise. You should always disconnect your rca's before messing with your power or ground cables. Especially don't hook up your power wire without the ground hooked up while your rca's are hooked up.

I think you might be right. I found out the amp thump was happening because my sub amp would not power down even when my coax amp was. They share a remote turn on lead, and have a common grounding point. With everything off my amp was still powered, so I removed the turn on lead and it stayed on. Next I unplugged the RCA's and noticed when I unplugged the top input jack, the amp powered down; plugged it back in, and the amp powered up again. I hope my HU isn't toast now. //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif