Amplifiers: test every channel and control

Start at moderate volume with simple settings. Test one input and channel at a time, then work through all advertised functions.

Check:

• clean and drive channels;
• gain, EQ and master controls;
• built-in reverb or effects;
• effects loop;
• footswitch if included;
• any attenuator or power modes.

Move pots and switches slowly to detect drop-outs, noise or unusual changes.

A feature that is “never used” can still affect the amplifier’s value. If it has not been tested, make sure it is clearly described as untested.