Hi Jakob,
Since my mains are 230v i would think i should wire violet and black to the powerswitch
you're right ...
I would then leave yellow and red on the transformer disconnectet.
yep, but you should isolate the "open ends" with a kind of rubber tape or better "heat shrinkable tubing"
About the Pin Layout of the power switch:
I don't have a data sheet of your power switch ... but if you have any problems to figure that out - please consult someone who is educated in electronics.
Furthermore - please make sure that you accomplish a proper grounding and connecting of the protecting earth conductor !!
Cheers
Stoffel
-----------------------
Warnings !
Caution is necessary. Even though this isn't a particularly powerful amp, it nevertheless works with voltages with are potentially lethal.
This amp is NOT appropriate for beginners!
Reading and understanding schematics, use of measurement devices, and good experience with voltages over 60V are prerequisites for the successful completion of this project.