PROS / It's light and efficient, and its combination numerical and graphical target ID is great for long-term hobbyists.
CONS / The detector's 8-inch concentric search coil is nothing special.
VERDICT / The Teknetics Delta 4000 offers good quality and great target ID features in an easy-to-use metal detector.
Teknetic's modern take on metal detecting is exemplified in its new series of detectors, all of which have been named after Greek letters. As the line's second-tier machine, the Delta 4000 should more than satisfy both newcomers to and veterans of the treasure-hunting hobby. It boasts superb build quality and features you won't find anywhere else, which is why it earns our Top Ten Reviews Bronze Award.
Design & Performance
Many of our metal detector reviews cover similar-looking machines. Sure enough, the Delta 4000's outward design is tried, true and perhaps a little boring. Its extender rod slots into a classic S-curved frame, while its control box is mounted just below the machine's lower bend – standard fare for metal detectors. The grip's padding might be wrapped a little too high on the frame for some users, but it's made of soft, rugged foam that's easy on your hands, painless to hold on to and hardy enough to last for years.
It's the control box that makes the Delta 4000 really shine, since it offers both numeric and graphic target ID. Many beginner detectors only feature graphic target ID, classifying targets into visual categories that make the detector’s feedback easy to understand. More advanced detectors tend to use numeric target ID. Numeric ID gives a number, usually between one and 99, that corresponds to a target's conductivity. It's far more precise than its graphic counterpart, and if you learn your machine, you can start recognizing exactly what it is you've found beneath the surface based on these readings. It's also brutal on new detectorists because, until you've memorized what every number or range means, it isn't particularly helpful. By offering both graphic and numeric ID side by side in this detector, Teknetics has stepped outside the mold. The result is a detector that gets better as your experience in the hobby grows.
Although its target ID capabilities are nice, there's nothing particularly special about the Delta 4000's search coil: a standard, 8-inch concentric option you'd find on any starter detector. You can elect to buy a more advanced replacement and switch it out, which you may want to do if you live in an area where the ground is particularly trashy. Concentric coils aren't as good at discriminating between close targets as DD coils are, due to the shape of their search fields.
Coil aside, the Delta 4000 has all of the features you'd expect from a metal detector tailor-made for treasure hunting. It comes with three-tone audio, nine sensitivity settings and six levels of discrimination – and that's in addition to custom notching, so you can ignore the trash you're not interested in finding and focus on the good stuff. The only downside to its feature set is its lack of ground balancing. You can use the sensitivity settings to reduce ghost targets and random noise, but that also reduces the detector's depth in highly mineralized areas.
When it comes to battery life, the Delta 4000 is excellent and convenient. The system has been optimized for efficiency, and the detector gets a solid 20 hours of battery life out of a single 9-volt battery. Fewer battery replacements mean a lower overall operating cost and less chance of having a hunting trip cut short. After all, it's not hard to bring a single battery with you as a backup, should the need arise.
Help & Support
Like Fisher and Bounty Hunter, the Teknetics brand is owned by 1st Texas, which is the largest maker of metal detectors in the world. The Teknetics Delta 4000 benefits from this with a five-year parts and labor warranty, detailed instructional videos, and great service and support.
If you're concerned about using a simple search coil or losing the benefits of ground balance, you can move up to a higher model in the Teknetics Greek line. The higher-end metal detectors in the series pack extra features that would wow hobby veterans, but they're proportionally more expensive than the Delta 4000. If you're okay with a basic coil, though, the Delta 4000 is one of the best metal detectors for beginners we've seen.