Brian Gaff wrote:

-------------------


Maybe in the case of my switch then what I shouldhave done is to take it out
and use it on mains for a few days.


** Bonkers idea - the switch needs replacing.

Switches are very much "horses for courses" and ones rated at mains voltage may fail to work at 12V or lower. Speaker signals require switches that have low on resistance at the millivolt level which implies the use of silver alloy contacts or better.

There are two major issues with large mains rated toggles when used with less other than mains voltages.

1. The contact material ( often plain brass) tarnishes with a non conductive layer. Regular use at mains voltage usually prevents this layer building up.

2. Grease applied to the moving parts of the switch migrates to the contacts, hardens and stops conduction.

In case 2, a squirt of WD40 often restores good operation, far as being a mains switch is concerned.

IME, speaker switches fitted to amplifiers are either rotary or slide types, the latter may have a toggle like action to fool the user. Both use silver alloy contacts and are self wiping in use, essential to keep tarnish build at bay.



..... Phil