View Full Version : Any Kenwood owners having thump sound problem when using CD track advance?

12-27-2006, 11:00 PM
I have the Kenwood Excellen XXV-01D and there is a slight thumping sound (noticeable when car is off and quiet) whenever I toggle the CD track forward or backward. I DON'T have the on/off amp pop nor do I have any similar noise issue when I tested the car with Eclipse or Alpine head-units. That said, I don't think it's a grounding issue and all my RCAs are no were near power lines.

I'm thinking this is an isolated issue with the head-unit but could be wrong.

Nine Five LS
12-28-2006, 03:03 AM
i have an older... kenwood mpv 622 (i think) ... and it does the same thing. I never noticed it until i tried it with the car off. Its hardly noticable and really doesnt bother me though. I can only faintly hear it coming from the subs.

12-28-2006, 03:11 AM
I have/had a similar problem with my alpine. It's like you can feel the CD operation. Doesn't happen with the radio. Only when I pause the CD or switch tracks.
It doesn't do it all the time and that makes it hard to T/S. When I couldn't take it anymore, I would be all prepared to fix it and I couldn't make it do it.
It actually hasn't done that in like a month now. It was really bad when I was in SanDiego at night when it was humid/foggy with a lot of dew outside. But in the morning it would be fine.
I believe it's a grounding problem with the head unit itself. I also noticed that when the problem was occuring my amp would shut off at high(er) volumes.

12-28-2006, 03:43 AM
i think its normal. mines does have a slight buzz but that when volume is maybe under 10 and car is off and no road noise. but it doesnt bother me.

12-28-2006, 12:13 PM
Maybe it's the PHAT noise :)

Honestly though, What the hell. I can't find it's S/N anywhere. You guys got that? Excelon likes to have an S/N of 98 or better, but I can't find it for this unit, and Kenwoods home site is as detailed as fingerpainting.

Oh ya, thumping seems to be associated with bad RCA pre-outs, RCA line ground issues, ground loop isolation, and crappy built decks. Also, when turning the car on, it could be the external amplifier does not have the right circuitry on the board to avoid the power-up thump, but I'm not sure if that is what you are talking about.

I blew the RCA-preout grounds off the deck and it would thump and makes all sorts of noise even with the car off. Try doing this:

But, before that make, sure to isolate your issues.

Best way to do this is to leave your amp and remote wire together, so that it powers up with your system, but disconnect the RCA's from the rear of the deck. If your gains are where you want them, and you still hear noise, it could be the amp or the RCA's.

Try listening close to each speaker to verify whether or not it is one specific speaker that is worse or not.

Then, disconnect the RCA's. If the noise is still existent, then you either have the Gains to high or your amp is not up to par with your own listening standards.

If it does seem to be the deck (which your description leads me to believe) try to find a good bolt that you can run a small 16 gauge wire too. Take 2 or 3 runs of 16 gauge (I just split the speaker wire I had left over from an install) and wrap them around the RCA pre-outs much like the OP in the above link did.

If you have room, plug in your RCA's before you touch that ground wire to the RCA-pre-outs, turn on the deck. Then touch the ground to your RCA's and see if the thump/noise dissapears as you operate your deck. If it does, your solution was eliminating the ground loop from your deck to the (probably still factory) Ground point that was provided.

12-28-2006, 12:26 PM
"I DON'T have the on/off amp pop nor do I have any similar noise issue when I tested the car with Eclipse or Alpine head-units."

Just re-read this and realized reading comprehension > me :(
I'd try to ground the RCA-Pre-outs to see if that helps, because it still sounds like it could be that (from experience). Or it's just a bad deck design.

12-28-2006, 08:37 PM
Interesting. I'll look in to it. Thanks Frank.

12-28-2006, 09:08 PM
Mine does too, but you can only hear it from time to time no big deal really.

12-28-2006, 10:28 PM
Mine does too, but you can only hear it from time to time no big deal really.

What model is your Kenwood unit?

12-28-2006, 10:59 PM
KDC-X-589 and it sounds wonderful!