Tesoro Electronics Eldorado
By Andy Sabisch
From Page 50
July, 2001 issue of Lost Treasure

Tesoro Electronics has been building high-quality metal detectors at affordable prices for more than 20 years. Treasure hunters from around the world routinely report their successes while using Tesoro detectors to the factory. My wife and I have used Tesoro detectors since they first opened their doors and we have always had a high degree of success in the field with them. One of the models the Eldorado was first introduced more than 10 years ago and provided above-average detection depth in the worst ground. It quickly became a favorite for relic hunters and detectorists that needed a unit that could handle bad ground. As Tesoro moved towards the smaller control housings of the Max series, the original Eldorado was discontinued; however, hunters from around the world asked for a replacement that offered the same features and performance. Tesoros owner Jack Gifford listened and after months of development, released the new Eldorado which offers enhanced performance in a smaller package.
As I mentioned in the preceding paragraph, Tesoro introduced a new control housing for their detectors a few years ago that incorporated surface-mount circuit boards and sub-miniaturization of the electronics themselves. The result was a series of detectors having a Max prefix with the housing measuring a mere 3 1/8 inches wide by 2 3/4 inches high by 2 inches deep. Add to that the fact that the detector is powered by a single 9V battery that provides up to 30 hours of operation and one can see why the Tesoro design team deserves a pat on the back!
The Eldorado has four knobs and two toggle switches on the control housing face to control the units operation. The function of the controls on the housings face is similar to many of the current detectors in the Tesoro line. The SENSITIVITY knob serves a dual role it turns the unit on / off and allows the user to adjust the power output from the coil. The DISCRIMINATE knob allows users to select what type of objects will be accepted or rejected. The THRESHOLD knob is used to set the audio threshold heard when the unit is in the All-Metal operation mode. The GROUND BALANCE knob is a turn control that is used to adjust for varying ground conditions. The MODE toggle switch is used to select the search mode All-Metal or Discriminate as well as provide retuning capabilities when hunting or pinpointing in the All-Metal mode.
The FREQUENCY toggle switch allows the user to select one of three possible operating frequencies (10.2 kHz, 10.4 kHz & 10.6 kHz) which is extremely useful when using the Eldorado in competition hunts where other detectors may be operating in the same frequency or in areas where electrical interference may be more pronounced at one frequency versus another.
The Eldorado comes with the new 9"x 8" concentric coil with an open center which offers exceptional ground coverage with each sweep yet is light enough to be used for extended periods of time without fatigue. Tesoro offers a wide range of optional searchcoils that can be used on the Eldorado. If you plan on hunting in high-trash areas or near metal objects such as bleachers, parking meters and the like, a smaller coil is definitely recommended. Another recommended accessory is a coil cover for the standard coil. The searchcoil manufacturing process leaves a slight lip on the bottom of the coil which tends to hang-up on tufts of grass or rocks as it is swept; however, the use of a coil cover eliminates this concern.
The three-piece rod assembly is another Tesoro plus found on their Max series of detectors. Combine the small breakdown size with the Eldorados 2.2 pound weight and you have an detector that can easily be packed in a briefcase or small carry-on suitcase.
A 1/4 inch jack on the back of the control housing is designed to allow a set of stereo headphones to be used which not only helps one hear the fainter signals but extends the battery life as well. Battery life from the single 9-volt battery ranges from 10 to 20 hours.
Field test
The first area I took the new Eldorado to was a defunct high school in the center of the town we live in. Built in the early 1900s, it has been worked and re-worked by countless detectorists over the years. A factor that allows old coins to be found at many sites in the central Pennsylvania area is that coal has been used for heat and the ashes were usually dumped around the buildings resulting in highly mineralized ground that can mask good targets. Starting in the front of the school near the sidewalk, I ground balanced the Eldorado, set the SENSITIVITY at the near the MAX position and the DISCRIMINATE level to FOIL. Slowly scanning the grassy area, I started to get some chatter so I turned down the SENSITIVITY knob to the preset mark and readjusted the GROUND BALANCE. This resulted in virtually no falsing and I continued to hunt in silence. The first few signals turned out to be recently-lost coins just under the surface.
As I worked further into the front yard, I received a clear, repeatable signal that was fairly faint in the ALL-METAL mode. Cutting a deep plug to see how deep the target actually was, I checked the hole. The target was still in the ground so I removed another inch or so from the bottom. I saw a coin break free and wiping the loose dirt from the face, saw that it was a 1926 wheat cent. I hunted most of the front yard small as it might be and while I did not hit the mother lode, I did wind up with 6 wheat cents, a well-worn Mercury dime and a metal Cracker Jack prize from the 30s or 40s. All of the good targets had been deep yet produced solid, repeatable signals in the motion discriminate search mode. The signal strength was less pronounced in the All-Metal mode; however, I used that mode primarily to pinpoint the target once I determined that it was worth recovering.
The next outing with the Eldorado was with an 11-year old friend of my son, Erich Lichtner, who had come over to the house. He had never used a metal detector before and I thought this would be a good test of the Eldorado in terms of how easy to was to use and how comfortable it was for a child. We went to an old foundation a short drive from the house. After explaining the detectors operation to him and making the initial adjustments, he headed off sweeping through the underbrush. There was a fair amount of junk metal laying around from the old tin roof so Erich asked if he should make any adjustments. I had him turn up the DISCRIMINATION control and this eliminated the signals from the junk in the area. Over the next 30 minutes or so, Erich located several interesting artifacts from depths ranging from around 6 inches down to just over 12 inches.
I put on a mini competition hunt for my sons Cub Scout den at the site of an old farmhouse that dated back to the 1890s belonging to the parents of one of the scouts.
One of the teams used the new Eldorado and in addition to several tokens that I had buried, found three coins including a Kennedy half dollar, a piece of jewelry (brass with remains of gold plating) from the 1800s and a buckle from a horse harness.
The scouts were excited with their finds and said that the detector was a piece of cake to operate.
I had the opportunity to use the Eldorado at several other sites in the central Pennsylvania area and had good success at each of them. Most of my hunting recently has been in private yards or around abandoned buildings and the ground condition from years of dumping coal cinders leaves a lot to be desired; however, the Eldorados ground balance circuitry was able to handle even the worst conditions I encountered. I tried both the 8-inch and 4-inch coils from my other Tesoro detectors and was impressed at the level of performance obtained from the smaller coils in terms of detection depth and target separation. Over a three week period, I recovered nearly 30 wheat cents, several pieces of silver, artifacts dating back to the 1800s and various other trinkets that wound up in my find box.
The new Eldorado definitely follows in the footsteps of its predecessor in terms of performance. Tesoro has reduced the weight and enhanced the performance to produce a detector that can satisfy the requirements of even the most serious of hunters.
If you are planning on upgrading your current detector or want one that will not be hindered by adverse ground conditions, you need to stop by your local Tesoro dealer and take a close look at the new Eldorado.
The new Eldorado sells for $469 and comes with Tesoros limited lifetime warranty a feature that Tesoro has always offered and shows how confident the Jack Gifford is in the quality and durability of his companys products!
Call the factory at (800) 528-3352, write them at 715 White Spar Road. Prescott, AZ 86303 or visit their web site at, for more information on the Eldorado or to obtain a copy of their informative Metal Detector Information booklet. Be sure to mention you read about the new Eldorado in Lost Treasure!

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