Bridging head unit?

[azzfox]

Well Ive got this Pioneer head unit in my shed. Dont have the model number on me but its not new and its not old. Sort of in between lol. Being extremely sick of the rubbish on the radio I thought it would be a good idea to run it off a PC power supply which works a treat. Im using two house speakers that are not very big but 8 ohm and handle 70wrms each. It actually sounds pretty good

Its sounds clear and doesnt clip or anything. But the heatsink on the back of the unit gets too hot to touch! Im wondering if this is normal or if its because of how the speakers are wired. The front and rear channels are joined together leaving the L and R channels separate but doubling the output rather than just connecting them with the front channels. Is this wrong to do? Just figured since theyre 8 ohm and severely underpowered that it might give them more oomph! Or would you bridge it kinda like a 2ch amp by taking a + and - of each channel? Or not at all?

Ive read through the installation guide and it says nothing relative to this. Just when using a two speaker system use two channels and dont connect the other two to anything. Would this somehow still increase the power seeing only two channels are being used? This is only experimental by the way. If something goes bang or melts I wont be too sad over it

[StoneX]

The amplifier IC inside the head unit is not made to be bridged, that is why it is so hot. You need to run individual channels or an amplifier if you need more power.

[azzfox]

Makes sense lol cheers. Im sure I can live with two channels. Funny thing is I once had this setup in my old VN when I diddnt really have money to spend on speakers. Had the same two speakers sitting behind the front seats, similar pioneer head unit with the channels bridged the same way. It went alright and never noticed a problem. Luckily diddnt start a fire

[azzfox]

Changed it so only the front channels are in use and presto. Can leave it on for an hour and the heat sink wont even be warm! Diddnt think it would make that much difference. Plus it still sounds the same if not better so there you go lol

[StoneX]

Yeah, the type of amplifier used in head units is just not made to have the speaker wires linked together. You're lucky it didn't actually blown the amplifier IC

Good to hear it's fixed.

[azzfox]

Yeah lucky lol wasnt sure how hot theyre meant to get. Weve got an old pioneer that gets roasting on the front. Take the face off and touch it and it will almost burn you. Kinda like the heatsink on this pioneer. Thats the only one Ive known to get hot on the front and weve had it in 2 cars. This one and another pioneer I have dont get hot on the front and barely warm on the back when wired correctly lol. Might get warmer with 4 speakers and a work out though.

While on the subject do you know anything about kenwoods and overheating? Mate of mine had one in a VS which is now in a VX. He claims it never was a problem in the VS but now after a while it gets hot and distorts. He bought one for his girlfriends camry and it does the same thing. He called kenwood and they said its a feature to stop them overheating. Then spoke to an auto elec and he said it may be a power issue and to try running a new power wire straight from the battery. I installed these head units myself and all joins are soldered/heatshrinked and earthed to clean metal. He tried taking the new one back to autobarn to exchange it but they wouldnt accept it because it wasnt installed by them and will only send it off

[StoneX]

Overheating is generally caused by joined or earthed speaker wires... So if you're knowledgeable enough to install and solder/heatshrink, then grab a multimeter, unplug the loom from the head units and measure the resistance from ground to each speaker wire. None of them should be ground.

Your other Pioneer shouldn't get that hot either.