I just noticed your question thanks to Jason responding. I am a gold prospector, coin shooter and relic hunter. Most of my detecting is done in moderate to highly mineralized dirt. My main use detectors are the Nox 600 and 800. From my experience both of the Equinox 800 gold modes are very similar except for the factory default recovery speed being lower on Gold 2. So, theoretically Gold 2 should be a little deeper. Also, the gold modes have less features (filtering) than the other modes since they are single tone VCO without all of the tone breaks and tone pitch adjustments, which makes them a bit deeper on some targets. However, they also use the highest frequencies which may not be the deepest for higher conductive targets like silver but are killer on iron, small gold, lead, brass and even some copper.
So, to really answer your question, in my opinion from my experience the Gold modes are slightly deeper on lower conductors. I have dug 14"+ 3 ringers, shell casings and shrapnel fragments that my buddies with E-trac, CTX, AT Max, F75 and Deus could not hit, period using Gold 1 and Gold 2 and the stock 11" coil in moderate to high mineralized ground. However, the same goes for Park 2 and to a lesser degree Field 2. Park 2 is almost just as deep in my opinion, and is better at hitting a wider variety of targets like deep silver since it is probably not using as much 40 kHz as the Gold modes if any. I have recovered 13" V nickels, and 11"+ seated and mercury dimes using Park 2. Again, I was with other detectorists for some of these finds and they got nothing, no response over these targets and the Nox was clearly telling me that there was a nickel signal 12,13,14 or a silver dime signal, 24,25, 26 under the coil.
I also use Park 2 when I'm gold prospecting if I want more information about possible non-ferrous targets that I can't get using the gold modes. The Gold modes really hit tiny targets hard so be prepared to dig some phantom targets. So, I think it is safer to say that Park 2 is almost as deep as the Gold modes but the Gold modes are much more sensitive on very small targets like small nuggets, micro jewelry, lead and iron fragments, bird shot pellets, incredibly small pieces of aluminum, wire, screen wire, and tin fragments, etc.
Also, the "All Metal" setting is not a different search mode. It is something that Minelab has done for awhile which is a short cut for going between a set discrimination pattern within Park, Field and Beach (or Gold) modes with some targets rejected to instantly having all targets accepted within whatever search mode you are using. It is not deeper, it just lets you hear all of what is detectable under the coil with a quick push of a button.
If you are not going to do much gold prospecting and you don't need the wireless headphones, really cool WM08 Wi Stream module for you favorite wired headphones, a custom slot for your favorite program, and three times as many recovery speed, iron bias and audio adjustments, then get the 600. I do just fine with the 600 and use it for most of my turf hunting for coins and jewelry and at the beach. It is a fantastic detector.
Jeff
