Hello Ron,
The mode was AM.
There are some good posts during the spring of this year here that cover most anything you would want to know on settings in Disc. I am of the opinion that the comparison to the GBII may not be fair because his coil was a 10 inch oval. The high frequency machines of Whites and Fisher are still used by commercial miners to evaluate surface deposits in old beds. These machines are still the standard in many locations.They are looking for picker and better sized gold,:gramme-rs.
AZ gold is often small and can be expected as a rule. If you find the small ones the bigger will take care of themselves and will not be missed. The difference in our two machines was apparent when I became more aware of the display and not the sound of the target. The simplicity of the GBII was it's crowning glory and I can see why such a machine is so well favored, of course the F75 has virtues that are in an all together different realm.
Fine gold is not my target for digging but for pay dirt streaks, one wants to detect all to work those fines.
I did like the sound of the sweet woo-woo of the X70 and was really impressed- not knowing the machine, I found a fly speck of gold in less than two minutes. All I wanted to do is see if the coil cover cleaning did the trick. I knew there were sands from clean-up out wash and likely gold there. What I did not expect was the result, but with that came the understanding why that machine was not the darling it was touted as. The fisher man had a plastic cup to sort out small gold over the coil and I understood the recovery needed for the flake would be difficult. Once found, it was placed in black tape for further testing. I threw it on the ground and happily lost it. It was sub-grain in weight. The man with the GBII was well aware he was excluding fine gold and the large coil he used for coverage and depth was the indicator. He faithfully recovered pickers and gramme-rs, small enough to detect and worthy of his time. The same model recovered many ounces up to and exceeding the one ounce mark.
I am so glad the F75 does not have me stopping at every minute particle in the soil. It would drive you nutz in gold country. Gold was in the water, the plants, the soil and maybe even the air.
like the saying goes,..... size matters
SJ