Problem with my DSP-Z9?


Standard Member

I have been happily using my Yam DSP-Z9 with a subwoofer connected to the left subwoofer out channel for many months with no issues, however recently over the last week or so, everytime I change source or even skip a track on a CD or DVD (any change to the sound stream) I get a loud thump on the subwoofer.

If I move the subwoofer to the right subwoofer channel it is all fine.

Does this sound like a problem with the Z9? is this something that other Z9 people have noticed?

I haven't had the amp for very long so would be most disappointed if the amp has gone wrong so quickly :(

Any help or comments appreciated


How do you power up/down the amp/sub?

I can't remember the details but I think there is some kind of dampening circuit in the line-out/in sockets which normally blocks these noises but it's possible to blow that circuit over time if it recieces large voltage spikes from connected equipment being switched on/off.

Hopefully someone can give you more info, does sound like that circuit has been overloaded on the Amps' left channel from your description.


Standard Member
Thanks for the reply ailean.

I never power off the sub as it has a standby control. So I guess it is effectively switched off when I power on the Amp and only powers up when it gets a signal.

Annoying if this has happened though as I can't think what would have caused it.

I will send an email to Yamaha to see if they verify what you said, will be a pain to send off for repair, this beast is not light and only a few months old.

If anybody else has any ideas or confirms ailean then I guess its back to the shop for repair :(

Many Thanks


Active Member
My friend has just bought one of these amps and recently added 2 additional B&W 601's to make up the THX back channel and changed the sub to a B&W ASW700 and now gets a thump from the sub on DSP mode changes (DTS/DD/powering on/off etc etc)

I did notice his mono feed cable was damaged causing some popping when touched, which he immediately changed...

He hasn't tried mono wiring to either left or right only (was originally mono right, but we left it wired in stereo) and have now seen that your problem was specific to a single channel..

Did you resolve this, was it a circuit issue? Does anyone else know what it could be or is..?


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