Tube Amplifier Debugging Page

This page is designed to lead you through debugging a problem with a tube-type guitar amp. Just click on the appropriate links, making the appropriate tests as needed. This page fits older Fender and Marshall amplifiers best, especially in the sections relating to amplifier specific things like preamps, reverb and tremolo. However, the sections on power problems, hiss, and hum should work pretty well for any tube amplifier.

This page has proven useful to quite a number of people by the reports I've received. It's always possible that you'll find a bug in it, and I know that there are some situations that aren't covered, although I believe that over 90% of bugs are. If you find an error, or have a bit of debugging info to contribute, please email so I can include it.

Read this warning before doing any of these operations. The life you save could be your own.

Does your amp have....?
• No sound at all, not even faint hiss or hum, comes out of the speakers
• Faint hiss and/or hum comes out of the speakers
• Pops fuses
• Squeal at some or all control settings
• Putt - putts like a motorboat
• Hum
• hiss
• Popping sounds
• Unintentional and ugly distortion even when set for clean operation
• Low power or volume, or volume drops off
• Smoke or burning smell
• Intermittent operation
• Electrical shocks
• Reverb problems
• Vibrato problems
• Scratchy Controls