Too much boost I´d say, you have to decrease the volume on your amp if you don´t want some window glasses broken
or the amp itself.
Sorry for the misunderstanding, I mean the pop occurs when turn on and off the DPDT not the 3PDT. From normal SHO to Superheated.
Thanks for reply btw

Sorry for the misunderstanding, I mean the pop occurs when turn on and off the DPDT not the 3PDT. From normal SHO to Superheated.
Thanks for reply btw