Cheers, Appreciate the response and the contact for Jim re super-tuning.
I have read a lot of highly favourable and less favourable things about some of the gmT coils (inc. the Shooter DD and the Gold Max). The latter is a bit of a beast weight-wise as I understand it but it would be interesting to test a concentric coil on the GMT, assuming the local mineralization does not simply preclude using it to it full advantage.
I will chase Jim up about it but as I understand it (in theory), the methodology involves increasing the audio output to overcome the standard audio threshold limit and pick up faint target signals that would normally be hidden in the borderline 'hum' of generally used threshold setting. I presume running the gain as the max possible level would be expected, albeit limited in itself by the background mineralization of the target area being searched (and the preferred absence of trash targets)..
I may stand to be corrected but will make the assumption for now that utilizing the audio-boost function on the GMT performs a similar function of sorts but I look forward to reading Jim's technique on actually how it is performed and what if any are the downsides.
I guess what I described earlier in response to you question was the procedure for making the coil a bit hotter or more responsive, as opposed to super-tuning. It is commonly suggested by experienced users to run the Gold Bug II in a similar fashion, with both the threshold up a notch and gain (sensitivity) max'd. The GBII does at least have a volume control. Some PI (Minelab) users often run an auxiliary amplification pack which I assume further boosts the (weaker) 'response' signals. No doubt using a quality set of headphones (with matching impedance to the detector output channel) is considered to significantly assist with picking up those fainter signals. VlF or PI, same thing. I'm not sure of the output impedance of the White's Goldmasters, or for that matter the Fisher GB's (II, Pro, etc), Teknetics, etc or if one size fits all. The Koss UR-30's seem to be a good goto headset but has anyone ever researched this I wonder? However, there has been some good discussion on this here --> https://www.findmall.com/read.php?34,130739
if you were prepared to ship the coil to Portland then I would consider giving it a crack. I have to consider converting from Nz currency so Us$100 would be a full stretch for me at the moment. My wife already thinks I'm mad so I don't need to provide evidence in proof to that effect if I can help it. If you are agreeable thenit would need to reach him by next week as my son has been in Portland/Washington area for the past year but is due to fly out at the end of the month.
Let me know but in any case great talking to you. Regard, Jerry