Excerpt from a post made by Monte in response to a question by Andre on the old A & S forum, sometime in 1997 I believe.
"<i>Those models that will go lower into the discriminate range (Tesoro refers to them as the ED-180 models), such as Tesoro's Amigo II, allow adjustment of a variable
discriminate control into this lower range. Now, that gets you into an All Metal accept
motion mode, but a skilled operator can fine-tune these models.
The best I have ever used was probably the Gold Mountain GMT-1650 that was also
marketed as the Gold Mountain Cobra. Do **NOT** confuse this with the King Cobra they
offered, or the Cobra II manufactured by Discovery Electronics for Kellyco.
Gold Mountain, about a decade ago, came out with a King Cobra that was a turn-on-and-go
model that was a too-close copy of a Tesoro Golden Sabre with notch adjustment. They
then introduced the Cobra/GMT-1650 that was a manually ground balanced model and
featured a toggle switch that allowed you to select "High or Low" range for the discriminate
control adjustment. By selecting "Low" it let you fine-tune the discriminate control to just
knock out nails and respond wonderfully to near-by coins, such as those touching a nail or
with a nail laying directly on top.
If I were to help design any new model detector I would certainly like to see such a
split-control feature to allow advanced operation in the discriminate mode........Monte</i>"
After I read that post I started looking for a GMT 1650, took a couple of years to find one but it has been well worth the effort it took to locate. It's the best vlf in trash, at least ferrous trash, I've seen. Below is a post I made on the Metal Detecting Equipment forum in 2000.
<img src="http://www.imageuploading.com/ims/pic.php?u=2342rG1OJ&i=21954" align="right" vspace="2"hspace="2"/>"<i>Spent a couple of hours after work today at an old football field here that was used from 1915 until 1958. There have been hundreds of coins taken out of about a 30' X 30' square where the concession stand was but it hasn't given up anything but recently dropped surface coins in years. It 's been hunted by dozens of folks with just about every detector made since the early 60's. I've hunted it at least 75 times and used various Garretts, Tesoros, Newforce, Whites, Fishers and Sovereign, including using small coils. The last silver coin to come up was a lone dime barely 2 inches down I found with a Sovereign 3 years ago and that was the first older coin in 6 or 7 years from the spot. It is literally carpeted with steel bottle caps and nails like in the pic. I used a Gold Mountain GMT 1650 with 8" coil there today and found the coins in the pic. The dimes are two 1917's and a 35. The nickels and wheaties are 30's, 40's and early 50's. Buffalo has no date and the junk ring is copper or brass. The GMT is better in iron than any Tesoro, or anything else, I've had and has surprising depth considering it's age. The coins were only 3" to 4" down except one nickel that was maybe 5", but a lot of us with big dollar machines left them in the ground.</i>"
I pulled a total of 19 coins from that spot with the 1650 that myself and a lot of others couldn't pull out of the trash with any of the many other detectors we've used there. I've rehunted it many times, including with all of the detectors I've bought or traded for, since I made that post and the only older coin found was a 1930 wheatie right against a big rusty nail, and it was also found with the 1650. I still have and use the GMT 1650, it's one detector I won't let go.
JB