popping noise from my speakers


I have a pretty high end system with Vandersteen speakers and all PS audio electronics but I get a regular popping noise coming out of my speakers. 
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all PS audio electronics

Have to be both channel tubes to go faulty at once, highly unlikely. Don’t think PS Audio use common rectifier tubes for both channels, think that stage is all solid state.
The only common thing to both channels is the transformer, I doubt it’s that
https://www.stereophile.com/images/617ps.ins.jpg
https://i.pinimg.com/originals/df/f6/e4/dff6e4d089c2fd09309a560a722e52a6.jpg
Cheers George