Creative PlayDock Z500 loud audible speaker hiss.

Question

I ordered a Creative PlayDock Z500 Portable speaker system from Amazon and the unit has come from Avides Media AG in Germany.
Unfortunately there seems to be a fault with the Z500, because there is a loud audible hiss coming from the speakers.
The hiss is the same despite the Vision M player in the docking station playing music or if there is no player docked.
If you play music and turn up the volume, then the hiss is drowned out by the music which is fine for rocking tunes. But for the more chilled songs with quiet parts the hiss is very noticeable.
The other strange feature about the hiss, is when the you turn the volume up with no music playing (or no player docked) the hissing gets quieter. As you wind the volume down the hissing gets louder, until you reach the minimum volume point then the speakers just go silent. Then just one rotation click clockwise then brings the speaker hiss back again.
I have read plenty of rave reviews about the sound quality of Z500, and I can't believe that this hiss is present on all units.
Has anyone else experienced this problem, and better still successfully had their unit replaced?
I have started the ball rolling by sending an email to Avides to see if they will replace my unit.
Cheers
Si

Answer 1

I am from New Zealand, our output is pretty much a stable constant 230V. Dad is an electronics expert, he disagrees with a lower voltage - lowering the input voltage will only lower the output volume. So in effect this will make the hiss appear to go away, but in reality it's simply lowered to a point where it's nominal or below hearing. The total output volume is also lowered, so you need to turn the speakers up more to hear anything.
It fits with what others have said about repaired systems, that don't go as loud any more. This isn't the fix.
We tried putting some heavy capcitors accross the speakers to act as a sort of high pass filter but that didn't appear to have any effect, which surprised him (if it had worked it would have killed some of the treble range also as a side effect, so again not a perfect solution). So it needs to be something a little more involved - like a decent filter of somesort.
It's probably just a cheap chip on the amplifier. I'm trying to get the company to find a NEW pair from the suppliers that doesn't hiss, then doing an RMA. Otherwise I"m tempted to get a refund, since IMO they're just **bleep** sounding. I've never heard hiss like this before, no matter how cheap the system. My DDTS-100 decoder seems to have a hiss problem also.....