As I indicated earlier dirtscratcher, some preset ones do work better, and some don't, it depends a great deal on how far positive they are set at the factory. Frequencies used are another determinant. Again, the F2 does better with its slight positive preset than the Aces and in this case the Eurotech Pro do with their excessive preset (internal) positive settings. The F2 is set to produce better results in a (broader) range of soils than the other two (the Euro, and the Aces). Tesoro uses a tank circuit which allows a faster retune to pre-ground balance, and that gives them an edge in good behavior over all the others here mentioned, and so do the other low-end Tesoros. In fact, as I said earlier, the only real differences between the Compadre and the Eurotech is that the Europech likes iron and steel artifacts slightly (barely) better than the Compadre. The Compadre however again, is not over-driven with high gain like the Eurotech, so it runs a lot smoother here (and in Montana too) since it is preset for the milder soils.. It gives the detector an edge in depth there, but not here where you and I play. The Compadre punches through the ground as well, but discriminates even better, cleaner, quieter than the other aforementioned save for the F2. If over-driven in gain, then the whole set of parameters becomes a different set of rules. In air, the Compadre measures about an inch less than the Eurotech and it comes to almost exactly one inch less, but in the ground it's a match for depth here. And although backing off with the preset positive setting gives harsh soil a better chance, it robs the milder soils the chance to utilize the extra gain cranked in to punch deeper. It's one of those "borrow from Peter to pay Paul" scenarios. The F2 and the Compadre both outdo the Aces (AND) the Eurotech in high iron soil, I have tested them all against each other so I know that it is absolutely true. The Vaquero you own does better than the Tejon too, I know, I owned one for those for awhile and traded it for a Browning a-bolt 338 mag, and I got the best end of the deal, its high gain nearly drove me to insanity as it tried to reject the bad ground. Remember, that the ground balance control in any detector is nothing more than a rough discrimination control, period. The Tejon really sucked on this side of the divide, noisy as all heck, but the Vaquero does very well as I have mentioned many times in the last 3-4 years. Whites Prisms though with their preset sit somewhere in the middle for decent operation because some of them have a "black sand" switch which moves the detector toward being even more positive. I have one just in the other room.. I have never in my entire life ever seen a preset GB work well in Oregon, Washington, Idaho, Montana, Nevada, Utah, California, Colorado, Wyoming, or New Mexico, the manual GB ones ALWAYS work better. Some operate so-so, but never as well as manual GB ones. . I now own about 30 metal detectors and have worked in design, repairing, and manufacturing thousands of them. Gold nugget hunters commonly use high frequency IB (vlf) detectors with manual ground balance, unless all they can afford is something that doesn't have it. Hope this helps.. PM me and I'll explain the hows and whys of manual vs preset or "automatic" GB, or you can read George Payne's dissertation on the subject. Just type George Payne + Ground balance in your browser. George is why we have what we now have in detectors, he is the instigator, the Godfather of ground balance detectors.
