Visually inpect every solder joint to see if you missed soldering one. Cutting out after a few minutes is usually something that happens because something expanded as the amp warmed up and shifted, losing contact.
If everything looks good, redo your voltages while in the amp is warm and post any big deviations from the figures in the manual. If you can find what is getting disconnected we can isolate the problem.
« Last Edit: September 22, 2014, 11:45:47 AM by Doc B. »
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.