[SeeSeventy]

There is no pattern what soever including temperatures. I can see that maybe as some point someone has fiddled with something here and had the amp out, as a result the water pipe from the aerial seems to have been brought up a bit. Enough to allow water to gather below the amp and drainslowly through the plug. It would explain the white powder on the DIN cable and of course it' slightly worn feeling.

I am investigating the amp further, see if any damp has caused damage to the PCB or connectors. Again, even with the new lead it seems better but not fixed or cured... It runs the entire length of the car, bought as a replacement. I also find that playing with an aftermarket unit gives very poor results. Although there doesn't appear to be any hissing or whining the volume is low and very weak, lacking the bass.

Thanks for the input, I think I can safely operate on the amp for the moment and assume that this is the cause. I am likely to say that the head unit is okay. The 3CD has stopped working altogether now, just loads over and over, but I can live without that.

I'll begin operations with MP3 tomorrow and try to finally nail the amp as the cause. If they were cheap and readily available I'd just buy another one at this stage. But we'll see how we get on tomorrow evening.