how to test power transformer tube amp?

To test a power transformer in a tube amplifier, first ensure the amp is unplugged. Use a multimeter to check the primary and secondary winding resistances; they should be within expected ranges. Next, apply a low AC voltage to the primary and measure the output voltage on the secondary to verify correct operation. Additionally, inspect for any signs of physical damage or overheating. Finally, check for any unusual noises or vibrations during operation.