Minelab X-terra 70
By Andy Sabisch
From Page 12
May, 2006 issue of Lost Treasure

Minelabs recent introduction of the X-Terra 30 and 50 did what many of their previous detectors did when they were first introduced--they took the treasure hunting community by storm with innovative and unique capabilities which were not just repacked features but rather proved themselves in the field under actual conditions where it counts. The X-30 and 50 were met with overwhelmingly positive feedback from users worldwide in the areas of performance, weight, balance and ease-of-use. Minelabs engineers--hating to look like the Maytag repairman sitting around with nothing to do--forged on following the release of the X-30 and 50 and developed a new X-Terra, the X-70.


The X-70 builds on the proven features of the other X-Terra models and adds a number of new ones that further enhance its versatility and performance. Due to space limitations of this report, the features common to all three X-Terras will be covered briefly with more details provided on the features unique to the X-70.

The first feature that strikes one about any of the three X-Terras is their configuration and weight, the X-70 with the 9 coil and batteries weighs less than three pounds and is extremely well balanced, making even extended periods of searching enjoyable for all hunters.

While the X-Terras are single-frequency VLF-detectors, Minelabs engineers have addressed some of the limitations found on this type of circuit. On a typical VLF detector, the manufacturer selects a specific operating frequency. This selection will correlate to what types of targets it is best suited to detect; i.e., a lower frequency will detect deeper but is less sensitive to smaller targets and those of low-to-medium conductivity such as brass or gold while a higher frequency is more sensitive to these targets but does not detect as deeply. When searching for different types of targets such as coins, relics, jewelry and gold nuggets, the choices were to sacrifice some sensitivity to certain targets or buy more than one detector. The X-70 allows the operator to change operating frequencies simply by changing search coils!

Thats right--the detector recognizes the coil that is connected and will change frequencies accordingly from 3kHz to 7.5 kHz to 18.75 kHz. Just pick a coil that meets specific needs and stick with a single detector. Another shortcoming with most VLF detectors is mediocre performance in the wet areas of saltwater beaches. In order to reduce the falsing that typically occurs, one has to drop the sensitivity or alter ones hunting style. The X-70 has two distinct ground balance modes--one for land and another for beaches--which allow the detector to compensate for the effects of salt and black sand resulting in greatly improved stability and detection depth in these areas.

Another addition found on the X-70 is the PROSPECTING mode which is entirely separate from the COINS mode. With the press of a touchpad one can switch from a high-performance target ID discriminator to a sensitive prospecting detector.

The X-70 is controlled through a set of 11 touch pads on the face of the housing. They are POWER, PATTERNS, ALL METAL, MODE/AUTO, MENU SELECT, PINPOINT / DETECT, ACCEPT/REJECT, GROUND BALANCE, TRACK and [+] / [-]. Information about a detected target, current settings or possible adjustments is shown via the large LCD screen in the center of the housing. Adjustments available through the MENU function include sensitivity, volume, noise cancel, threshold and tones. Sensitivity is self-explanatory. The volume and threshold circuits allows for separate levels to be selected (and retained) for headphone and non-headphone use. A headphone icon will appear when headphones are plugged in letting the operator know that the headphone settings are being used. This allows use of a lower volume and threshold setting with headphones which can improve battery life.

The X-70 will also automatically reduce the volume once the battery strength reaches the LOW level to conserve power and extend hunting time. Noise cancel offers five settings (-2, -1, 0, +1, +2) which shifts the frequency slightly to reduce or eliminate any outside electrical interference--the factory preset value is "0". This can be adjusted manually or by pressing the AUTO touchpad, the detector selects the optimal value.

The X-70 uses individual notches in the COINS mode to determine what targets are accepted or rejected. The X-70 has a total of 28 notches (four negative numbers corresponding to ferrous items and 24 positive number corresponding to non-ferrous targets). Another change from the other X-Terras found on the X-70 is the ability for users to select the number of tones one hears when a target is detected ranging from one (all targets sound the same), two (ferrous / non-ferrous), three, four and multiple (designated as 99 on the menu screen; i.e., each notch has its own tone). By allowing users to select what is more useful to them, the X-70 helps any hunter identify targets both by tone and visual indication.

The X-70 has three discrimination patterns which can be easily customized and are retained when the power is turned off as well as an All-Metal search mode.

The ground balance circuitry on the X-70 has been designed for ease-of-use and can handle a wide range of ground conditions--from neutral soil to black sand and saltwater beaches. To ground balance the detector, simply press the GB touchpad, lower the coil to the ground, press the AUTO touchpad then raise and lower the coil a few times until a number appears on the screen. To automatically track ground conditions and change the GB setting as required, press the TRACK touchpad and its ready for the hunt! In alkali soil or saltwater beaches, switch to the BEACH GB mode and perform the same steps to eliminate the effect of the ground conditions.

For those that want to do some prospecting or hunt in a true all-metal search mode, the X-70 offers a dedicated PROSPECTING mode. Pressing the MODE touchpad switches between the COINS and PROSEPCTING search modes. When in the prospecting mode, the X-70 is operating in a non-motion all-metal search mode. A circuit available only in this mode is called Iron Mask and encompasses a range of 0 to 20. As the value is increased, some ferrous targets are rejected; however, this control should be used sparingly since small gold nuggets can be rejected along with the ferrous trash--get some specimens to practice with before heading out into the field. The prospecting mode can also be used for beach or relic hunting when maximum detection depth is desired at the expense of having full discrimination and target ID. During the field test I used this mode at a few sites and found that switching to coins by pressing the MODE touchpad allowed me to ID louder signals and if no response was received on the fainter ones, I would recover them--in many cases finding keepers at impressive depths.

The pinpoint circuit is another useful feature found the X-Terras. When the pinpoint touchpad is pressed, the non-motion VCO-based pinpoint circuit is activated and the display changes to show a moving ring that forms a complete circle when the coil is centered over the target.

The audio response also aids in pinpointing by increasing in both volume and pitch as the coil approaches the target center. Combining the pinpoint circuitry with the depth indication provided through five arrows, each indicating approximately two inches in depth, the X-70 allows for extremely accurate pinpointing and rapid target recovery which simply equals more "keepers" at the end of the day! The X-70 will also provide updated target ID and depth readings if the sweep speed is increased slightly in the pinpoint mode which is helpful in locating a keeper amongst trash or once it is out of the hole.

A final feature that deserves mention is the Target ID Stabilizer. Most VLF detectors tend to lose target ID accuracy in highly mineralized ground; however, Minelabs engineers incorporated an algorithm into the software that allows users to activate this feature in adverse ground conditions to improve the consistency and accuracy of the visual ID indications.

The X-70 uses four AA batteries that fit into a compartment integral with the housing. Alkaline cells will provide 20-plus hours of use and rechargeable batteries can be used with no adverse effect on performance. A headphone jack is located behind a protective rubber cover on the left side of the housing. Headphones with a 90-degree plug are preferred over the straight-plug design based on the jack's location and will avoid possibly damaging the plug or cable.

Field Test

Due to space limitations on the print-version of this report, the actual field-testing will be summarized; however, more details are available on-line.

There are several well-hunted sites near my home that I take most detectors to in order to see how they stack up to the competition. After all, what does hunting a virgin site really tell you; i.e., could any detector have found the targets?

The first site was a large open field near the local college which had both new and old targets interspersed and in some areas, extremely challenging ground conditions. Several hours of hunting over a three-week period turned up a generous helping of coins including three silver dimes, 11 wheat cents and a Buffalo nickel. Ground balancing, even in the most mineralized sections, was a snap with the AUTO feature and the TRACK circuit kept the X-70 properly balanced as conditions changed. A little experimentation with the Target ID Stabilizer feature in the hot areas netted me the Buffalo nickel, 3 wheats and 2 of the silver dimes--all from areas others and I have searched previously.

A few old home sites in the woods gave me a chance to see how deep the X-70 could detect targets as well as handle the ferrous trash that littered the sites. In each case the discrimination circuit allowed me to ignore most trash by either eliminating the trash entirely or producing clipped or erratic indications that were easily discernible from the good targets. Several artifacts were recovered from depths up to 18, including an 1800s axe head.

A point to be aware of is that the X-70 provides experienced users the ability to increase the sensitivity level to the point where the unit may become unstable; i.e., falses and chatters. While there may be certain times where this extra edge is desired; running at lower sensitivity settings will result in much smoother operation while still providing above-average detection depth. At several sites I ran with the sensitivity set at 16 or lower (out of 30) and easily detected coins and similar targets at 8 plus.

Unfortunately I was not able to take the X-70 to any of the gold areas in the Southeast to fully test the Prospecting mode; however, in talking with some users that tested it in the Nevada gold fields, it performed on-par with or better than some dedicated gold machines costing as much or more than the X-70.


The X-70 builds on the performance of the other X-Terra models with the addition of several new features and an entirely new Prospecting search mode. Its weight and balance allows for extended hunting without fatigue. The automatic ground balance and noise cancel combined with the track feature proves for above-average performance in even the worst of ground conditions with minimal operator involvement. And the most innovative feature of the X-70 is the ability to tailor it for the specific type of targets being searched, simply by swapping search coils. What other detector gives detectors in one control housing!

The X-Terra 70 retails for $849 and comes with the 9-inch, 7.5 kHz concentric coil and skid plate. Optional accessories from Minelab include Koss headphones, a durable rain cover, shorter lower shaft and search coils of different operating frequencies, sizes and designs; i.e., Double D or concentric.

For the name of the nearest dealer, more information on the new X-Terra series or the rest of the Minelab line, contact Minelab USA at 871 Grier Drive, Suite B-1, Las Vegas, NV 89119, call them at 702-891-8809, or visit their web site at and be sure to mention reading about the new X-Terra X-70 in Lost Treasure magazine.

Minelab X-terra 70

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