When you turn the GB Pro on you are turning the knob on the Left, the gain, the power, all the same. There are no numbers. Turn the gain knob till you hit the 11 o clock position. Now go to the knob on the Right , the discrimination, the all metal mode, threshold, all the same. Turn the right hand knob to the right until you are comfortable with what you are hearing. You have to have to hear some threshold so that signals will break it. Push the ground grab button down while pumping the GB Pro coil up and down close to the ground and you will see the numbers on the screen line up pretty close to the numbers in the bottom right side of the screen, when this happens you are ground balanced. At this time if your threshold is warbling, not steady or eratic then turn the gain a tiny bit towards the 10 o clock position or until it is nice and steady. Depending on the ground you are working you may be able to go higher on the gain and some ground will force you to go lower on the gain. As you are detecting you are hearing the threshold and if there is a difference in the sounds and it is not staying where you set it at then you need to rebalance with the ground grab button again.
While you are detecting swing the coil as close to the ground as possible and go at a speed which will enable the threshold to maintain. There is no set speed to swing the detector at, just so you maintain a steady threshold. If you swing to fast in a particular area and the threshold is breaking up then you will miss subtle signals. As you learn your detector you will find little tricks you can use that will make things easier. I would not use the discrimination mode for normal gold detecting. The GB Pro will pick up the same tiny pieces that the GBII will but not in discrimination mode. If you are detecting in a high trash area and you have gold that is bigger than a gram then you can detect in the discrimination mode and it will work for you.
You guys still using the GBII, it is a great detector, I have literally found pounds of gold with my three over the years. It was hard for me to change from the GBII to the GB Pro. In my opinion the GB Pro just does so much more when you learn how to use it. It goes far deeper on big and little. It works in soils that the GBII had to fight. It stays balanced better. It is waterproof. It has a far easier learning curve for beginners. The GB Pro is far cheaper, less batteries, longer battery life and the discrimination on anything over half a gram is fantastic. For those not wanting people to know their business it breaks down into a pack better. As stated above I know the GB Pro will find the same tiny sub-grainers as the GBII can, only difference is it does it with more ease as far as I am concerned. These are all my opinions, TRINITYAU/RAYMILLS
