Head unit to home speaker hook-up...

[Evil Elvis]

Hi Guys, recently fitted a decent pioneer unit into my van and coupled it up to some nice 80's Cambridge Audio speakers that someone gave me years ago... The whole thing sounds great but after a while the sound cuts and although the CD is still playing I've got zero sound coming from the speakers... I leave it half an hour and the sound is back... My question is... Do I need to install passive crossovers as per the original speaker configuration or is there something a little more sinister going on...?
If anyone on here can shed some light on this I'd be most grateful and I'll not be offended if you need to explain it to me like a three year old as electrics is not my first language...
All the best, Mark.

[sternal]

home speakers and car/stereo/ speakers use different ohms I believe

[Evil Elvis]

I believe that the unit is 4ohms and the speakers are 8ohms which shouldn't throw up too much of an issue. I have done the same thing a few years ago on an old school Mini and all was fine...

[ghost123uk]

Ah, but, It's not just a case of less current flowing due to the higher impedance of the 8 Ohm speakers (over the usual 4Ohms for car style ones). the 8 Ohm "home" speakers will only produce 1/2 the volume (in dB) as 4 Ohm ones, so the volume has to be turned up a lot more to get the same amount of sound. This will likely be over-driving the output chip(s) and the protection circuit may well have kicked in. It's lucky your head unit has this protective cut off, many don't and would have burned out their output chip(s). As Elvis points out, sometimes, with some chip types, you can get away with it, other times not.

To test if I am right, set it going with the volume on so you can just hear it clearly, but not at all loud, leave it on for a while and see if it still cuts out.

Aside - just in case, if you are tempted to test it using some 4 Ohm car speakers, that are just bare speakers, not in a case, as per the type you fit to an internal panel, it is not good practice to use them at any loud volume unless they are correctly fitted to a panel. Reason being the "bass" sound waves can easily flow around the edges of the cone and in doing so cancel themselves out. This results in what sounds like little bass or volume, so you turn it up and finish up overloading them without even knowing it.

p.s. No you don't need a crossover, your Cambridge Audio speakers already have on built in.

[Evil Elvis]

Now that makes sense... I'll plumb in some 4ohm car speakers and test the system as per your instructions... Thanks for your input guys, I'll keep you posted...
All the best, Mark.

[Evil Elvis]

All is good... Got no sound, even out of some 4ohm Pioneer car speakers... Popped the head unit out and quite by chance found a short from the live line... Having repaired said short I beasted the system (and the street) with half an hour of the Sex Pistols... So far the system has performed with zero faults so I'm hopeful that the issue is sorted. Thanks to everyone for their help and input... All the best, Mark.