Head Unit Amps Off for Sure?

[Flyin11]

For years up until about a week ago, when driving a pair of component speakers at 34/40 on the volume gauge, which would likely be it's 22Wrms/ch max, for say 20-30 minutes, the ejected CD (by me) would be quite hot to the touch. Enough that I wondered if one would maybe warp someday, heh. The HU only once in three years showed the OH (overheat) indicator and that was with no A/C in the cab, on a very hot day, and running the HU loud.

Joe

Exactly what happens to me on my Kenwood MP4028. As discussed before in this topic, my HU overheats after having the volume at 28-29 out of 35 for a extended period of time. My cd's are hot to the touch and so is the face of the HU after I take the faceplate off. Sometimes the faceplate is warm as well. Still worries me...even if I get a new HU cause the Honda Civics (I have a 2003 Civic Ex) dash panel where the radio is, is all cramped and sealed tight that would still lead to overheating even with a new HU. No space for air to move around or get back there to keep the radio cool. Plus, it's very close to the air ducts and heating system behind the panel which could also cause more heat to the radio. I don't entertain the idea of trying to add a fan behind the radio either as noise could easily get in and it would draw more power from my electrical system. I'm not adding another amp for my highs either. That would be way too much current draw and it would make my lights dim...plus, 22watts rms is plenty enough highs for my 4 speaker system.

 

[PrecisionAudio]

Good luck Flying11. I think perhaps a small fan behind the head unit, strategically placed, would help and not create any noise at all (electrically or acoustically). But, from what you said about cramped spaces, that may not be easily possible. As I mentioned in my Pioneer unit's space, it does get very compressed where it needs to be installed.

I'm just trying to help increase the cranking, cooling, and longevity of your system here. Again, good luck!

Joe

 

[PrecisionAudio]

Update: My Pioneer model 8600 does in fact allow the user to selectively turn-off (completely defeat) the front speaker and/or rear speaker head unit amplifiers! This choice is available via the front and rear speaker high-pass crossover slope screens and 'activated' by holding down a specific remote control button. And, I thought I knew the HU's manual by heart...oops.

So, with the rear door speakers completely removed and highly electrical taped to prevent a short, I was able to 'turn-off' the HU's signal presumably sent to that amp. On a side note, I want optimal front sound stage so the rear speakers were of no use but rather bothersome to me anyway. The Q-Logic kick panels provide excellent staging.

But, though I'm using the HU's front speaker RCA outs to drive the stereo JL amplifier, the 'amp circuit' must remain active. Turning that off also turns-off the RCA output (bummer).

So, this will hopefully help lessen the heating of the HU in the future (i.e. with the HU's rear speaker amp off). On a long drive today, with substantial volume playing, the ejected discs did seem much cooler to the touch but it is around 15 degrees here in Minnesota so the jury is still out (grin).

What is nice though is that I can now much more easily disable ALL component speaker outputs so that only the subwoofer gets signal and this will greatly assist me in tuning that, ya know?

Thought someone would like to know, heh.
Joe

 

[jol50]

I had a couple of cars that I drilled holes in the heat/AC duct behind the radio, that worked great. I tried to find the dash vent duct since you use that for AC and not much for heat. Even if it is close to the rear of the HU it gets some air moving back there and helps. I did have one truck I had to run the defrost to cool the HU in the summer, it would get hot once in a while. It was the only duct there. I use PC case fans on my amps, they work great and I got a few for $1 each with an order to some place a while back. I would never have an amp in my HU except that only the most expensive ones come without. The only time I used one was in a car that had 6 speakers stock. I had it running all of them and put a cheap 8" powered sub tube in the back that kept up no problem. It sounded good, but far from impressive. That car really didn't have room for anything else and I didn't have time to mess with it.

 

[ppia600]

Update: My Pioneer model 8600 does in fact allow the user to selectively turn-off (completely defeat) the front speaker and/or rear speaker head unit amplifiers! This choice is available via the front and rear speaker high-pass crossover slope screens and 'activated' by holding down a specific remote control button. And, I thought I knew the HU's manual by heart...oops.

So, with the rear door speakers completely removed and highly electrical taped to prevent a short, I was able to 'turn-off' the HU's signal presumably sent to that amp. On a side note, I want optimal front sound stage so the rear speakers were of no use but rather bothersome to me anyway. The Q-Logic kick panels provide excellent staging.

But, though I'm using the HU's front speaker RCA outs to drive the stereo JL amplifier, the 'amp circuit' must remain active. Turning that off also turns-off the RCA output (bummer).

So, this will hopefully help lessen the heating of the HU in the future (i.e. with the HU's rear speaker amp off). On a long drive today, with substantial volume playing, the ejected discs did seem much cooler to the touch but it is around 15 degrees here in Minnesota so the jury is still out (grin).

What is nice though is that I can now much more easily disable ALL component speaker outputs so that only the subwoofer gets signal and this will greatly assist me in tuning that, ya know?

Thought someone would like to know, heh.
Joe

Wow, that's awesome. I never saw that feature in the menus. Glad you found it.

 

[jpruden]

On a side note, some Alpine units allow you to turn off the internal amps.