Introducing the GPZ 7000

In 1987 I bought my first VLF metal detector, a Minelab GT 16000. In its day it was very innovative thanks to automatic ground balance; because I live in a country where the gold field soils are extremely variable, even in the quieter areas, an auto ground balance feature along with a circuit designed from the ‘ground up’ to work well in mineralised soils was a real boon.  

Then in 1995, almost 20 years ago to the day, Minelab released its first MPS PI detector, the SD 2000, I was fortunate enough to have been there in the front row very much a part of a worldwide phenomenon as the Minelab brand rapidly rose to become the household name it is today. The gold that was discovered in Australia and elsewhere in the world was mind boggling; huge nuggets were discovered only inches below the surface because the mineralisation had been too severe for Continuous Wave (CW-VLF) detectors, demonstrating a very large proportion of the world’s gold fields at the time could still be considered virgin. In the last 20 years a lot of those once virgin areas have seen the attention of every Minelab PI machine and coil configuration imaginable, so even though theGPZ 7000 represents a quantum leap forward in technology the gold still has to be present for you to then find it. So will the GPZ 7000 be like the SD 2000 experience all over again? In my experience NO more than YES, but on some very memorable occasions I’ve been left wide-eyed and shaking!  By way of explanation here are some similarities and differences across platforms between the GPX 5000and GPZ 7000.

The Many Similarities:

• The GPZ 7000 audio sounds very much like the GPX 5000

• Target signals at a distance from the coil sound similar to GPX

• There is a Tone control

• There are Normal and Smooth type Search Modes

• There is an Auto and Manual frequency Tune control (called Noise Cancel)

• There is a Gain control (called Sensitivity)

• There is Automatic and Manual ground balance

• There is a Threshold control

• There is a Stabilizer control (3 settings available called Audio Smoothing)

• There is a Quick-Trak button (to activate fast ground balancing)

In essence, the GPZ 7000 will sound and feel extremely familiar to GPX 5000 users.

The Main Differences:

• New ZVT technology (Zero Voltage Transmission)

• New Super-D coil configuration

• Integrated battery (high capacity Li-Ion)

• Internal routing of coil cable

• LCD control panel and easy-to-use menu system

• Wi-Stream wireless audio (similar to CTX 3030)

• GPS and Map screens (like CTX 3030)

• USB connection to XChange 2 (like CTX 3030)

While the mechanical platform is based on CTX 3030, there is new advanced electronics inside!

Search Mode/Timings Comparisons:

GPZ 7000 Search Modes = Similar GPX 5000 Timings

• High Yield/Difficult = Fine gold

• General/Difficult = Enhance

• High Yield/Normal = Sens Extra

• General/Normal = Sharp/Normal

My experiences with the GPZ 7000 have varied from reasonable to nothing short of amazing. The results have been in the form of tiny nuggets that compete with the SDC 2300 to nice mid-sized pieces clearly missed by the GPX 5000, and then on to jaw dropping occasions where I’ve found numerous large slugs up to 15 ounces that were at great depth. Using the supplied GPZ 14 coil I’m more than happy to take on an SDC and pretty closely match it for performance on the small stuff (except for tiny surface gold, but this is more down to coil size rather than sensitivity). On quite a few occasions I’ve gone back over well gridded patches and found gold missed by the SDC, so the micro to gram sized ‘bread and butter’ gold is well and truly covered. 

With the GPZ 7000 I’ve generally attained similar or better performance than a GPX 5000 with a 18” Monoloop - this has been in both the Difficult and Normal Ground Type settings (depending on ground conditions) in combination with either High Yield or General Gold Modes compared to the 5000’s Fine Gold or, where possible, Normal or Sharp timings. The go-to mode will definitely be the High Yield/Difficult combination (the detector comes pre-configured in the High Yield/Difficult mode). Because the ½ ounce down to sub gram gold in mineralised areas is more plentiful, I highly recommend to users, who have found patches in noisy ground with Fine Gold or Enhance on the GPX series, to revisit those places with the GPZ 7000 in High Yield/Difficult to see what might be still lying in the ground, especially if those patches have never seen the attention of older Minelab detectors using Normal timings. 

The GPZ 14 Super-D coil cannot really be compared to a Double-D on the GPX 5000 in behaviour although there are similarities. Because it is a balanced coil like a Double-D it does provide some Double-D like behaviour over the ground in regards to ground response, however the ZVT technology behaves a lot differently compared to MPS with DVT, so the GPZ 14 coil should really be thought of as being similar in regards to ground signal noises as a Monoloop on a 5000 rather than a Double-D coil. There are some real benefits with the GPZ 7000, in that it is now highly recommended you use the Auto ground tracking feature when detecting even in the Difficult Ground Type setting. This helps smooth out ground variations immensely which are much more aggressive with the ZVT technology compared to a GPX using Fine Gold and a Monoloop in Fixed. The Auto ground balance of the GPZ 7000 is by far the most refined ground balance I have ever used.

In summary, the GPZ is rock solid stable with real world performance. I’ve had incredible successes with this new detector with nugget finds down to 1 metre in depth happening on frequent occasions along with other incredible discoveries which when cross checked with the GPX 5000 and various coil and timing configurations would not even respond. A savvy operator who learns the intricacies of the GPZ 7000 with ZVT will reap the rewards both in new and old ground. ‘Out of the box’ it’s a simple switch-on-and-go performer that has serious horsepower. Get to know its capabilities and suddenly you open up a whole new world of possibilities.

Lastly I would like to extend my heartfelt thanks to the quiet achievers at Minelab who have worked tirelessly alongside Bruce Candy to create this incredible detector; it has been an honour and a privilege. I look forward to elaborating further on the exciting new GPZ 7000 in future Treasure Talk blogs.