Audio Systems: intermittent sound from stereo, rca cables, fuse block

Question
hardware: aftermarket JVC in-dash AM/FM/CD player, pre-amp out to external Blaupunkt amp, powering Boston Acoustics component speakers, each with its own crossover

problem: Sound intermittently cuts out.  Typically after going over a bump.  Occasionally, going over another bump restores sound.

symptoms: car stereo remains on.  amp remains on. gently pounding on dash or amp does not trigger or solve problem.

I thought the problem was in the in-dash unit, so I replaced it with a new model and the same problem occurs.  The wiring isn't loose (it wasn't before, and I redid it with the reinstall).

So, I'm not sure where the problem is, but hopefully you've seen this problem before.  Is this a symptom of a grounding problem or a short?  Something else?  How can I check and fix it?

Thanks  

Answer
Craig,

  its in your wiring from your unit back, could be as simple as a ground that gets jarred loose over a bump, best tip to cure this is completly redo your wiring for the amp and crossovers.... check all your wires all your connections, on the terminals use a touch of blue loc tite to prevent bass round out that can cause a loose connection... you already eliminated the head unit as a suspect and since everything dies it has to be in the wires feeding the main components... you might also give some special attention to your turn on wire and your RCA cables make sure the RCA cables are in good condition and even try a new set, for the turn on i always recommend using the 12v ignition fuse for a good source either from the fuse block or from the head units harness ... hope this helps you out.. i know its a task to redo everything but it will insure you can eliminate the problem

thanks

CM