Mesa Dual Rectifier PSU Film cap

[hylaphone]

Hi, can anyone explain the purpose of that .047uF film cap at the input of the choke?

Is it a bypass for noise from the diodes?
Or is some kind of resonant filter?
If it is a critical value, how does one go about calculating?
Thank you!

[The Dude]

I think it's to minimize popping when the standby switch is closed.

[Mike Sulzer]

Could be it is to stop the voltage across the switch from going too high when it is opened.

[hylaphone]

Thanks guys. No head scratching either way