WTF???

[jandl100]

Craig, honestly ... it's obvious.

The wife knows all about the amp on top of the cupboards. Wives know everything.
She's taken out a life insurance policy on you with a special insanity clause. If you end up in the loony bin she cops a £bundle.

It's all a sneaky plan to drive you (even) mad(der).

[AJSki2fly]

You are probably sited right over the top os a lay line and gateway to a parallel universe, how do you think I got here?

[Barry]

I assume it's on the same circuit as other kitchen devices.Some of these are very noisy when switching on & off.Kettle,toaster,microwave,washing machine etc.

I sometimes hear a click on my system in the lounge when stuff is switching in the kitchen.My best guess would be a mains noise spike.

I'm inclined to go with this explanation, especially if the amp is within close proximity of the fridge/freezer etc., and hence offering two paths for interference: mains borne switching spikes conveyed through the wiring and radiated due to the thermostat contacts arcing.