Hello Ivan,
Just picked up an SST this morning, took the long drive but had a chance to detect for an hour before starting work.
Don't have an M6 to compare the SST with but did have an MXT with same 6"x10" DD which I recorded on paper test results on various coins and a gold nugget before selling the MXT.
Using full sense with both the MXT & SST and these are air test not actual buried targets, The SST fared better across the board on all targets both low and high conductive.
1" to 2" inches more on the SST with the exception a penny air tested 2.5" inches further than the MXT, a noticeable increase on all conductive both low and high.
However, The iron audio is so close to the lowest conductive audio on the weaker foil pieces that it's going to take a while to train my ears on the weaker lower conductive signals. Gold nuggets will sound so close to iron audio will take a while to train the ears, the audio difference is noticeable but will take a bit to get the weaker signals down.
I counted four tones, if that's all it has that's enough for me. I'm a two tone hunter lowest for iron the second audio for non ferrous, but I can already see liking the SST once I train my ears to master the audio break between iron and the lowest gold range tone.
Gain is noticeable, hope this extra horsepower carries out in the field. One other noticeable feature is the weight, felt like I was swinging a feather. Feels much lighter than the MXT?
Paul (Ca)