Originally Posted by scooby9
The strange thing is that it wasn't a problem before but it is now. It could be that the amp is defective now...
Do you know anyone with a spare aftermarket amp that you can swap in to test if the hiss is still there? If it is, then it is a wiring or source unit problem. If not, it's probably the amp. The PDX series are still D-Class amps which are generally noisier.
Thanks, its a good idea. I can change my JL slash amp to drive highs and mids to see whether the noise is there. But the JL has S/N rate above 100dB, and PDX only 76dB, the dealer may refuse my claim. I don't know how should a 76dB S/N look like, so am still looking forward for some PDX user experience.