E-Wave 30 watt combo...

[David Martin]

All three tat min and no sound... But it's the bass control which actually turns everything off...

[Twang46]

All three tat min and no sound... But it's the bass control which actually turns everything off...

Well yes, but if the mid control did not earth the wiper at minimum position it would not happen.
This is the type of tone setup in Fender twin amps etc..... that this amp is mimicking, it's a very popular Blues Junior mod for example

Dick.