Head unit clipping

[TRaGiK 10+ year member]

I have a Pioneer DEH1100 that powers my door speakers. The pre-outs are hooked up to a Memphis PR500 that drives a Type R 12.

On songs with a lot of bass, the head unit will sometimes clip the front speakers, but ONLY of the sub is playing. If I cut all power to the amp, the clipping stops. If I disconnect the sub from the amp (but leave the amp powered up), the clipping stops. If I disconnect the RCA's and leave everything else hooked up/on, the clipping stops.

The sub never clips as far as I can hear.

Any idea what my problem might be?

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[djman37 5,000+ posts]

you are drawing voltage down on the ENTIRE system, HU included.

 

[TRaGiK 10+ year member]

Just checked for that.

Normal voltage with the truck running with radio and all accessories off is 13.85 volts. With a/c and headlights on, and the sub thumping, it drops to 13.40 at the battery. I checked voltage at the battery, amp, and head unit. At the head unit, voltage drops to 13.35, and the amp drops to 12.9.

I'm pretty skepticle of it being a voltage drop issue since it's dropping less than 1/2 a volt, at the HU and still well above 13 volts.

Any other ideas?

FWIW, the head unit doesn't start clipping the door speakers til after it's been playing for 5 or so minutes (after it's sat for 30 minutes or longer). I thought it might be over heating as it gets pretty warm on the heatsink on the back, but even after turning it off for a few minutes and letting the a/c blow on it, it still clips.

 

[djman37 5,000+ posts]

that's all i got. you might try upgrading the size of the power and ground wires running to your HU since it is powered.

 

[TRaGiK 10+ year member]

If voltage were dropping alot lower than it is, I think that'd be the only time upgrading the size of the power wire to the HU would be beneficial. No?

Anyone else have any suggestions?

Is it possible that a brand new HU is junk, and giving me these problems?

 

[TRaGiK 10+ year member]

Anyone got anything else?

 

[TRaGiK 10+ year member]

Found the problem. HU was bad. Replaced with a better Pioneer HU and all is good now.