My Matchless amp was purchased used earlier this year; it didn't come with a manual and in fact, I've never seen a manual for a Matchless amp. It has a half power switch on the back and 4-8-16 rotary click switch. It's a combo amp in a 1x12 cab, loaded with an 8ohm Matchless speaker which plugs into an internal speaker jack. There's also an external speaker jack. What I don't know is if you're supposed to switch the output down to 4ohm when playing at half power. Anyone know?