Hum Debugger

Some good things to know about the Hum Debugger: by EH

The Hum Debugger has two modes of operation Normal and Strong. We recommend you use Normal mode to remove hum unless it does not remove enough of the hum, then switch to Strong. So always start on Normal mode.

We recommend that the Hum Debugger be placed at the very start of the signal chain before any other effects. (However since effects later on in the chain can also pick up some hum, it can be put at the end of the chain...but then since the effects can introduce new harmonics.. the hum debugger might eliminate some of these as described in the problems below).

The Hum Debugger tends to work best on clean guitar signals So it is most useable with single coil guitars but it can also clean up humbuckers that do not completely remove hum. It also works best with single notes and simpler chords, and with minimal note bending.

While the Hum Debugger definitely removes hum, there are some artifacts that some guitarists might find change their sound too much.

Normal mode sounds much closer to the original guitar than Strong mode. In Strong mode, if the guitarist bends a note from B flat to B (B flat is a bit below 120hz and B is a bit above 120hz... so the bend could make the 120hz note drop out) (assuming the guitar was tuned to standard 440 concert pitch). This is due to the a filter notch at 120 Hz. in the STRONG mode. ( 120hz is NOT removed in Normal mode. )

However in BOTH Strong and Normal modes if you bend from F to F# ( moving over 180hz ) there will be a dead spot. ( 180 is removed in both STRONG and NORMAL modes )

Also in Strong mode, it can sound like the guitar has a very fast slapback delay on it. This does not occur in Normal mode.

In Normal mode, the Hum Debugger filters all of the odd harmonics of the hum: 60 Hz, 180 Hz, 300 Hz, 420 Hz, etc

In Strong mode, the Hum Debugger filters all of the harmonics both odd and even: 60 Hz, 120 Hz, 180 Hz, 240 Hz, 300 Hz, 360 Hz, etc.