New sound problem with PS3.. overheating? bad cable?

Hey guys!

I'm confused by this one..

I have a PS3, plugged in to my amp with HDMI cable, which then sends the signal to my TV through HDMI too. Yesterday, the PS3 started sending "crackling" noises to my back speakers on/off... really weird, I'll be playing some game, it does that, then as soon as I pause it stops... If I continue playing, eventually the sound goes off. I then have to switch the source of my amp to something else, and come back to PS3 to get sound again.

I tried other sources (TV box), it works fine, no crackling.

I tried plugging the PS3 to my amp with optical cable: instead of crackling noise, I get this super high pitched noise through the speakers...

so I understand that it is not the HDMI that's at fault (cable or connector). I thought maybe the PS3 could be overheating, causing this (we've left it on for over 24 hours in a row I think), but then again it does not freeze or get visual glitches. Even when the sound is messed up, I can still play fine (controls and visuals are A-ok).

I'm currently letting it cool completely... any ideas?

I know this probably isn't too helpful of a response but my PS3 completely loses audio if I leave it on all day. If I shut it off for an hour and turn it back on it seems to be just fine. If you have problems as soon as you turn on your system then obviously it's comething else but if it only appears after several hours then it could very well be related to overheating.

I would say its the amp having problems with the PS3's decoding the audio signal its recieving. Does it only happen whilst playing or even with the XMB?

Do you have any Blu-rays you could play?

Hey guys my PS3 was making really bad crackling sounds after I installed the v3.40 especially for Dragon Age Origins.

After some extensive fiddling about I've found that going to "Music Settings" on the PS3 and making sure the Output Frequency was on 48khz and changing the Bitmapping option to Type 2 the noises have stopped.

I hope this option helps some others out.