Been following the threads over on the Prospecting OZ Forum about Doug and several others claiming the GPX-4000 is missing nuggets in the "Sensitive/Smooth" mode. I can't honestly comment on this, since I haven't tested the Smooth mode at all.
I do know for a fact the GPX-4000 in the "Normal/Deep" mode was able to outshoot my GP3500 hands down with the settings cranked up past the Factory Default Settings. The GPX-4000 heard a very small nugget, a nugget right at 7 Dwt's and another at 1 ounce deeper than the GP3500. This is the only test I have concluded with the GPX-4000 vs. the GP3500.
I'm going to do some testing this weekend on deep nuggets in the "Sensitive/Smooth" mode to see if there is actually a lose in depth. Kind of makes me wonder if there is a "dead zone" in this mode or it just has to do with the soil conditions in Australia.
I promise to keep you posted on my findings. This is the main reason I held onto the GP3500. The GPX-4000 seems amazing, but I want to make sure there are no bugs before I let the GP3500 go.
Here is a post I copied from the other Australian forum -
4000 and large nuggets in sensitive and smooth"
Not sure why those guys are having trouble hearing a larger nugget at
depth? I am guessing they are having problems with setup and or combos
of functions. I have no problem hearing large (planted) targets at
depth equal to my 3500, but struggled a bit at first learning to set
the 4000 up. This detector is not the same as an earlier GP series and
one must learn to use the settings properly to avoid such problems
since they can under most conditions be adjusted to suit most ground I
have encountered (in the US)"
Dear Bill Southern
The guys that did the testing are NOT having problems with the setup
of the 4000.They are extremely experience prospectors and users of all
ML machines and in fact have taught hundreds of others how to use ML
detectors over many years. Their testing over a number of days CLEARLY
shows that in sensitive and smooth that certain nuggets at certain
depths are NOT detectable with ANY size mono coil in sensitive/smooth
with the 4000. This has now been observed also on some VIRGIN nuggets
in VIRGIN ground ie nuggets that gave NO response in sensitive/smooth
were EASILY detectable in sensitive/extra/ deep. Bill you should accept
the findings and not question the ability of the testers or the
testing methods. The 4000 when used in sensitive/smooth has an
"ELECTRONIC HOLE" through which some nuggets including some very BIG
ones will fall. Unlike many forums including yours my forum is not ML
dealer run or controlled and is truly independent and I am sorry if
the testing results irk some ML dealers and promoters which is not
surprising as ML and the dealers are pushing the sensitive/smooth mode
on the 4000 very intensely. If people in the US want to get the best
results when the ground is suitable then they should try the settings
of mono lover as described on my forum with the gain adjusted
according to prevailing ground conditions and EM noise. At least then
they can be confident that they will not leave behind a good nugget
as they may if they use sensitive/smooth.