heat buildup at back of head unit too much?

[Biodieseler]

Hi everyone, I am just in the middle of swapping my cars Pioneer CD/MP3 player/radio into a new (to me) car. I am concerned about how much heat is being generated at the back of the main unit. It is only at the very back that it's getting super hot, and I had it on for half an hour or so and I touched the back of the unit and it was too hot to hold. I have a 10 amp inline fuse in the main power wire and it does not blow the 10 amp fuse built in at the back of the player itself, but still gets very hot. My question is, Is this normal? Or could there be something wired wrong causing so much heat?

I found it strange that my car only had one single wire going from the original radio to each speaker. There are 2 wires coming out of the new player for each speaker, but only 1 wire in the cars wiring. So for each speaker I hooked up one of the two wires out of the cd player and just capped off the other. The front speakers seem to work fine, though with a little crackling, and the rear speakers are very faint.

Could the strange car wiring cause so much heat at the back of the player? Or is it just normal that they get quite hot?

Thanks for any advice.

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[wickedwitt 10+ year member]

Part of the heat is you are apparently getting close to the max output of the head unit. Finding a small 2 or 4 channel amp to run your mids/highs would take that strain off of the head unit and therefore get rid of quite a bit of this heat buildup.

 

[AlterEgo99 5,000+ posts]

Agreed...be much better to, at the very least, go to an external amp and take the pressure off the H/U.

 

[Biodieseler]

Thanks guys... But this isn't to run any aftermarket speakers here... this is just to run the original car speakers in my 1986 volkswagen jetta. They're only about 15 watt speakers, and I only put sound to them for a couple minutes... The heat buildup is happening just from having the unit on. I noticed this while I was just organizing tools etc. in the car and didn't even have the speakers powered. I know some heat is normal, but I just about burned my hand on the back of the unit and wondering if I'll melt my dashboard or start a fire if I finish installing it as it is.

Edit: I just went out with my voltmeter and tested the draw it's taking. It takes 5.1 amps just to have the unit on, with the volume turned down completely. I can turn the volume up, and it makes almost no noticeable difference in how much amperage the unit is drawing. Within 2-3 minutes the back of the unit went from cold to the touch (around freezing) to quite warm. I could hold my hand on it, but not if I kept it on for another 2-3 minutes.

It was working fine in my old car, and never noticed any problems, but I can't see how it's going to not burn something back there if I leave this alone. That's why I'm looking for advice on what could be wrong.

By the way, I am doing this outside the dash as I've just been working to wire it today. So I have not put it in the dash yet. I won't if there is something actually wrong inside.

What would cause a 5 amp draw just to have it on? No wonder there's heat building up!

Thanks again

 

[wickedwitt 10+ year member]

Thanks guys... But this isn't to run any aftermarket speakers here... this is just to run the original car speakers in my 1986 volkswagen jetta. They're only about 15 watt speakers, and I only put sound to them for a couple minutes... The heat buildup is happening just from having the unit on. I noticed this while I was just organizing tools etc. in the car and didn't even have the speakers powered. I know some heat is normal, but I just about burned my hand on the back of the unit and wondering if I'll melt my dashboard or start a fire if I finish installing it as it is. Maybe it's normal to have that much heat just by having the unit on?

Whether the speakers are aftermarket or not, if you are running them from the HU, you are causing stress on it. You can get a 2ch amp for dirt cheap, and remove a bunch of the load from the HU. This will also help to eliminate distortion as the deck will be sending a digital signal via RCAs versus an analog via speaker wire. If you gain match the amp, and set it's xover well, you can actually get some clearer sound out of your stock mids and increase their longevity.

EDIT: If it's getting that hot just from being on, I'd see if there was any way to allow better ventilation around it, and maybe power it up outside of the dash to see what kind of heat it built up. Could be going bad, and yes if it's that hot, there is always a potential for catastrophic problems (fire)

 

[Pataforce8 10+ year member]

Whether the speakers are aftermarket or not, if you are running them from the HU, you are causing stress on it. You can get a 2ch amp for dirt cheap, and remove a bunch of the load from the HU. This will also help to eliminate distortion as the deck will be sending a digital signal via RCAs versus an analog via speaker wire. If you gain match the amp, and set it's xover well, you can actually get some clearer sound out of your stock mids and increase their longevity.
EDIT: If it's getting that hot just from being on, I'd see if there was any way to allow better ventilation around it, and maybe power it up outside of the dash to see what kind of heat it built up. Could be going bad, and yes if it's that hot, there is always a potential for catastrophic problems (fire)

I thought RCA's were analog? Just a much lower level than a speaker output.