I got the 1650 because Monte made several posts on the old A&S Tesoro forum to the effect it was the best detector he had used for hunting in iron laden places. The first few times I used it I didn't see anything special about it when hunting in iron, but I gradually begin hearing the differences in the audio when a nonferrous target was mixed in. The Classic seems to be different in that, at least so far, it gives a cleaner signal on nonferrous targets mixed with iron. Based on the simple masking tests I've done and my use of it so far, I don't doubt that it would match the 1650 in iron laden places once someone learns the how to use it at those type places. One thing that's a requirement is to use a very slow sweep speed. Yesterday I used my normal sweep speed, which is already very slow compared to the speed most others use, and hunted an area about 5X10 feet. I got a bottle cap, a couple of pieces of can slaw and a bullet. Then I went back over the same area using a very slow sweep speed and heard a few weak nonferrous signals the faster sweep speed missed. Those were a small piece of copper wire, a couple of pieces of foil and a piece of flat brass about a half inch square, but one or more of them could have been an old coin.
The Classic goes deeper than the 1650, but at places like the stage stop and inn site and a few others we hunted depth isn't an issue, and forget about coins giving a coin range signal. At those kind of places it's about a detector having the ability to average the combined conductivity of one or more large rusty nails and a coin and giving a nonferrous range signal. That's what made the 1650 special for hunting places like that, and why 70 percent of the coins found by the six of us who hunted there were found with the 1650. Unfortunately I'm not as physically able to hunt those kind of places as I was even a year ago, so I've been using it at places here in town I've already hunted with the 1650. As soon as I post this, unless the boss decides I need to do a chore, I'm heading out to an old home site here in town. I never used the 1650 there, but I've hunted it several times with the Barons using the 5.5 inch coils and found several wheaties and a couple of silver dimes.