How to Ground Balance a Gold Bug 2
Easy way to remember
From my website logtables I see that some visitors came here looking for this information, so here it is.
1) if you not using headphones, you should be.
Headphones or not, turn the threshold knob, the tiny knob located on the back of the machine, and turn it up untill you can hear the threshold hum.
2) locate a patch of ground with no metal signals.
3) Raise and lower the coil six inches or so a couple of times, and listen to the hum. When the coil is on the way down, does the threshold hum increase, decrease or remain the same ? If it does not remain the same it needs adjusting. Just to make it complicated, if the difference is only very slightly louder going down that is OK. Actually most agree desireable, known as positive ground balance.
4) Adjusting the ground balance knob. Which direction to turn it ? I had trouble remembering myself. So I Use this analogy, it works, and makes it easy to remember. Think of the GB (ground balance) knob as the volume on a radio. When the coil is on the down stroke and the threshold gets louder, turn the GB knob counterclockwise. Analogy, turn the radio down. If the threshold hum gets quieter on the way down turn the GB knob clockwise, Analogy, turn the radio up.
5) If necessary readjust threshold knob to a level that is just audible.
Summary: Louder down, turn it down, quieter down, turn it up.
This will apply to other metal detectors with a threshold based all metal mode as well.