AV2 randomly turns on my B&W PVD1?

Hi

I have a lovely but somewhat ageing 3.1 set up, being Naim AV2 + NAP-V175 (and DVD 5 albeit not used) running new HDTV, Apple 3, TiVo and Blu-Ray boxes into some B&W XT4 speakers (two main, one centre and PV1D).

All was working fine before adding the PV1D to the Sub output on the AV2. Now that has been added, it sounds great and powers up whenever there is .1 sound from the source. The PV1D is set up to auto switch on whenever it receives a signal from the amp. However, on many occasions, when all source units are off is off except AV2 which I keep on constantly (as is often recommended), there will be a medium volume level popping sound and the PV1D will switch on, i.e. the AV2 seems to randomly send out a .1 signal even though non of the source units are on (they are however on standby).

Any ideas?

Best

Amer