Minelab Pulse Induction Detector Modifications


World's Greatest Minelab Detector Modifications & Upgrades


We provide upgrades and modifications to Minelab Pulse Induction Gold/Metal Detectors:

We also provide a number of SD, GP and GPX accessories.
DetectorMods is a division of Link Technologies.

Minelab GPX 5000 upgrades

Thursday, the 13th of March, 2014

This is a fully upgraded Minelab GPX 5000 with new front-end variable gain and an extra timing switch for optimizing the detection of small, medium and large deep gold.
The variable gain upgrade is what most of the professional prospectors are using on detectors, it allows use of any sized mono coil on any type of ground to obtain maximum performance for detecting gold nuggets.

The use of the variable front-end gain while detecting in fine gold mode has been proven to detect gold specimens and deeper nuggets that would not have been able to be detected previously. The upgrades also include new filters for less EMI, and higher rated components are also installed to get maximum performance from any type of coil. The variable gain upgrade is opening up old goldfields that were thought to have been be worked out, and now prospectors are discovering many more gold nuggets with these new upgrades.

Gold Gem & Treasure article

Saturday, the 1st of February, 2014

An article recently published by the Gold Gem & Treasure writes…

This handsome nugget was picked up south of Ballarat late last year with a Minelab GP3000 that had been modified by Peter Woodland at Detector Mods.

Nugget found by one of our customers

Wednesday, the 18th of December, 2013

This nice nugget was found by one of our customers with a fully modified GPX5000 which we did for him two weeks ago. The nugget was found not far from the Enfield state forrest near Ballarat, Victoria. It was found at a depth of 25" close to a previously worked reef.

Modified GP finds big Nugget

Thursday, the 12th of December, 2013

A recent find published on the official Minelab website tells of a find found with a GP3000 detector. There is no mention in the article that it was a detector that we had substantially upgraded for the owner. Our upgrades find the Gold.

Latest Finds

Wednesday, the 6th of November, 2013

Found in Central Victoria with a modified Minelab GP-3000.

Hundreds of ounces of gold

Tuesday, the 8th of October, 2013

Over 2kg of Gold

Monday, the 1st of April, 2013

Found by a couple of mates in Western Australia

Good gold in the USA

Monday, the 7th of January, 2013

Nuggets found in the first three days of use, found by David D in the US, using our modded GP3500.

Gain Upgrades Non Stop

Below is a pic of a couple of the detectors we did this week a GP-3500, GPX-4500 and GPX-5000 , the variable gain takes some time to install but God are the results worth it

Variable Gain Update.

We Have proudly retrofitted our new variable gain sub-board into the all GPX Series Detectors and the SD-2200 units, we have had fantastic results following this new addition to our upgrade and modification capabilities.
We have been receiving alot of calls from our customers letting us know how much better they are doing, picking up many pieces they have missed on there most flogged patches!

Carbon Coils!

We are now making the coil windings for Chris Barret, who is creating these large carbon fibre beasts. To purchase one of these super-deep seeking coils, visit Carbon Coils.

New Variable Gain

For all you GP-extreme GP-3000 GP-3500 true believers we have a new upgrade that gives you variable gain over the input of the detector while achieving greater control over the ground mineralization, this will allow anyone to use a mono coil over any ground type, even salt lakes. This new upgrade is a vast improvement on the standard front-end design for these detectors. Our testing has shown that this upgrade allows you to fine tune the detector to the ground that you are working. The new sub board is fully gain matched for both channels to allow precise DD performance if you want to run in salt/cancel mode. This upgrade will actually give any GP series detector far more dynamic range than even the later GPX series.

Why do Minelab dealers hate us?

Do you need to go and spend over $6000 on a new metal detector to find gold? the answer is absolutely no!!! we can upgrade any older Minelab pulse induction detector to find larger and deeper gold. We can match the performance and even exceed the performance specification by using cutting edge electronic component upgrades. we will get you more gold with over 1800 proven upgraded detectors being used around the world. No wonder there is a campaign to discredit us. PS...5-year warranty on our work!

Victoria Gold Rush

There is a gold rush near Koorongvale in central Victoria. The recent heavy rain has washed out some of the gullies leaving gold nuggets on the bedrock. Large gold nuggets have been detected and have been shown on TV on channel 7. The area is north of Wedderburn.

New Upgrades.

we are currently developing a sub board assembly to be fitted into any Minelab pulse induction detector. This electronics interface board will greatly improve the detectors performance by allowing quite operation on any conceivable type of soil. This board will work in conjunction with all existing modded detectors.

GP-3500+30oz Nugget

Updates below 30 oz gold nugget found with modded GP-3500.
Hi Peter, I thought you would be interested in, Steve who visited me today. He is a novice who purchased a 3500 recently. I advised him to have you modify the detector, which he did. He went detecting recently in a well-detected area. he got a signal over a partly dug detector hole. It seems as if the previous operator had stopped digging thinking that it was just a ground noise. However, the superior depth of his modded GP 3500 told Steve it was metal, so he kept on digging until he unearthed a 30-ounce nugget! it was a spot that had been well detected. I visited that spot a few years ago and avoided detecting there as it was so obviously so well known and detected. Steve said that he is finding much more gold since he had the mod done.

Any way, I have attached a photo of the nugget which can be shown anywhere you like.
Jack Lange

Jack Lange Strikes Back.

The following is published with the full permission of Australia's best known and respected prospector.


Dear Peter,

I have been using your fully modified GP-extreme now for many months on the field and I should tell you that at present, it is the best gold detector I know of. My prospecting partner, Wally, has a Minelab GPX-4500 and my brother Ed has a GPX-4000. I have done numerous depth comparisons with both in real-life goldfield conditions and it detects deeper than the 4000 in all soils and at least as deep as the 4500 in heavily mineralized soils. In quiet, average soils it detects deeper than the 4500.
at times, Wally had to run his detector in enhance mode to handle the noisy ground with a mono and as you know, it loses depth in that mode, but I ran the GP-extreme on the same ground with a similar mono with no difficulty. however, because it has a perfect and I mean perfect threshold, which is stable at any level, in reality it is my preferred detector for depth and quietness in all conditions. It operated perfectly in overcast conditions last week with no apparent thunderstorms on the horizon. but the 4500 and the 4000 were hard, and at times, impossible to use because of the atmospheric conditions. The 'woody' GP-extreme was perfectly stable thanks to your most recent addition mod. Also on sunny days it ran quieter in terms of handling mineralized ground than the other two units. (which are in perfect working order by the way).
Yesterday, I found 10 nuggets (smallest was .4 gram with 24" elliptical coil) with it during some very relaxed detecting, while not having to try and decipher a genuine signal from interference noises. What a dream detector! I am including its charms in the present nugget finding secrets DVD I am working on.

Best regards and thanks for all the years of hard work you have put into these mods.

Jack Lange

Queens birthday test results...

Queens Birthday

Over the long weekend we carried out some serious testing of an upgraded GPX-4500 and a selection of coils including our newly patented design. the testing was done at the Laanecoorie test site near Tarnagulla in the central Victorian goldfields. We tested a selection of upgrades on the GPX-4500 detector as well as testing with 2 x 18" high inductance mono coils, 1 x 12" x 20" patented design and various commercial designs including the NF 12" advantage, Minelab 11" mono and a couple of 14" DD coils. 2 x new dual field coils were also tried and these coils may offer some hope for a coil design that can detect a greater size range of nuggets using one coil.
There is one thing that was very obvious to us when testing various coils with the GPX-4500 in normal and enhance modes of operation. The standard range of coils are not optimum for the enhance mode on the GPX-4500. The very narrow pulse width in enhance does not fully energize the coil inductance of any existing coils, enhance is a very good mode for noisy ground but it seems that there is a significant depth loss with some types of coils. We will be working to see if our newer coils can be optimized for enhance mode. Minelab have made a significant improvement for working noisy ground with enhance but newer specific coil types need to be developed.

hello peter, despite being busy in other ways than detecting, inclement weather and tall grass and thistles, I found 25 bits after having done mod. 2 on my 3500. These 9 bits I found in an area 8x8 m previously detected by me and very good operator, a friend of mine with 4500.i had found 3 other bits after him in this place with mod 1, and now these 9. Biggest is 1.4g, total 6.8g.they were all deep for their size. Apart from that I am finding gold again, in places, I have not been able to find anything in years.
Thank you,
Your grateful George.

GP-3500 Testimonial

Gold nuggets found with modded Minelab GP-3500 detector.

These beautiful nuggets have been found by George with an upgraded Minelab GP-3500 using the series 1 mods. He is sending his detector over to have the series 2 mods installed, I cannot wait for his next gold nugget pictures.

Jack Lange has been testing the series 2 mods with a Minelab, GP extreme detector, read his story in the may edition of Australian gold gem and treasure magazine. He found a lot of gold!!!

Jack Lange

Jack Lange of Gold Hunter Detectors, who is also one of Australia's best known prospectors has been out testing the new modifications on a Minelab GP series detector. The results according to jack are outstanding! Check out his site for information on gold prospecting.

The new mods have been field-tested and give outstanding threshold stability and no loss in sensitivity or depth. The testers have found that many signals that have been previously masked by a noisy threshold are now very distinctive target signals. This is indicative of the way enhance works on the Minelab GPX-4500. The Minelab detectors are still the number one choice for a dedicated gold detector, if you are at all serious about finding gold stick with Minelab.

Detector Test

A detector test by jack Lange of gold hunter detectors is coming out in gold gem and treasure magazine, he is using an upgraded GP-extreme detector that we did for him a couple of months back. Jack gets the same upgrades I do for every other prospector.

Nugget finds, while out at Kingower Victoria (where the hand of faith nugget was found) (875 oz.) I found a 3.5 gram in thrashed ground with the upgraded GP-3500.
I had a friend with me who asked to borrow my detector, he walked out of our tent and roughly 20 meters away had a signal, down around the 2' or 60 cm he pulled out a 127 gram nugget.

Rumor finds of large gold, Maryborough Victoria, 660 oz., Amherst Victoria, 2 large of 30 oz. And 16 oz. There have been some others reportedly found but the finders do not want their details made public.

In all cases these nuggets where all found using Minelab detectors.

Custom Coils

We are currently taking custom orders for very large mono coils up to 2 meters in diameter. Popular sizes are 36" and 42" size using our specially manufactured anti-interference shield material. Our coils can be shaped into any shape you require to detect large deep gold that has been missed by other prospectors with lesser coils. Big gold typically lies at 4' to 12' depth in many gullies. Check nugget depth historical references.

This is how I make my own large coils, the frame is made from 6 mm x 10 mm kiln dried pine, I stick it together with liquid nails. I make my coils in a hexagon shape as it is very easy to do. This massive coil can be lifted on my little finger it is so light. The coil is cable tied to the outside of the frame. It just needs some center mounts made from strips of wood and away we go. For extra strength the structure can be fiberglassed if you want. This is the way to make huge deep seeking Coils without the $1000 price tag.

We have developed some new coils for maximum depth on large gold nuggets. The coils are wound with new exotic materials to give superior performance without the superior price tag. We can also do custom coil designs including ground loops. There are area's that very large gold nuggets in the 50 oz. Plus size are found at depths of 4' to 12' deep, until now there was no way to find these huge nuggets. Our coils will detect these huge gold nuggets at depth not before obtainable with existing coil configurations. Below is a size comparison between a new high performance 36" coil and an 17 x 12 and 18" mono.

These coils can be mounted to your own frame, either plywood or a light braced pine frame. They can be shaped as a round or whatever takes your fancy.

SD-2200D Strikes Gold

The Seventh Day.

A member of Victoria's largest detector club has found some good gold on a very flogged to death patch in central Victoria using a lately modded SD-2200D.
The prospector and the club members have gone over this patch for some years, using every detector from the SD-2000 up to the GPX-4500. As not to rain on his parade, I am not going to give away any details until it is released in the club's newsletter.
Well, I feel for warren, he was pipped at the post by someone who found an old coin. The crystal 8 gram nugget was an excellent specimen, when catch up with him I will post up the picture of the gold.

Upgrades Update

I have just received a completely new batch of ultrafast soft recovery rectifiers that have 30% more current carrying ability than the mur320s types that Minelab use. The new types have less forward voltage drop and that means more current to your coil for greater depth. Last but not least is the intrinsic capacitance is less than half of the mur320s and this reduces capacitive loading of the coil and receiver stage to allow faster sampling and greater signal levels. Being a soft recovery rectifier means less switching noise and greater signal to noise ratio. These new components have been tested on SD GP and GPX detectors and have been found to offer a performance advantage.

More Testing

We can now match or even better the receiver sensitivity of the newest Minelab detectors. We have upgrade components that greatly improve the detection depth on the SD and GP detectors. The best way to get extra depth and sensitivity is so improve the receiver signal to noise ratio. We can achieve a 3db improvement in the current noise figure of the receiver front end that give a huge improvement in sensitivity and depth. No one else offers these upgrades as they have been engineered and tested by myself to be the best that there is currently available.

We are currently having some GPX-4500 detectors field tested with upgraded components and expect field test reports back in a couple of weeks.


The Fourth Day.

This is the email I received from Andrew who was on a prospecting trip to Tibooburra NSW. This came with the photo on the right.

now that I have put these pictures up it will cause great uproar in attempt to save face and protect commercial interests, this a cold hard fact but the pictures and correspondence is 100% true and correct. It is word for word from the owners of these detectors.
I have changed one word in (brackets).

just an update on the modified GP-Extreme...
I've just got back from a week in NSW with 15 other detectors, 13 of which were using new GPX-4500 machines.
after 7 days the extreme had found 21 pieces, second place
however it did get the greatest gold weight tally overall... There are some seriously (dejected) GPX-4500 owners this week!!!
see the depth of the photo attached... 4 pieces taken from this hole, I've never got 4 pieces from a single dig before.
go the GP-Extreme
thanks again!!!

A Job well done.

These picture have been sent to me by prospectors that are using a Minelab detector that has been upgraded by myself. The one on the left is from New Zealand where the gold won by a single SD-2200D was far more than the total of 4 experienced prospectors each using a GPX-4500 . Thanks Bevan


On the 13th June we carried out more testing with a new series of mods at the Laanecoorie test site and at the daisy hill gold field near Maryborough. The information that we gained tells us that the new series of mods are very good indeed. In very well worked ground at Daisy HILL a 0.9 gram nugget was found at 9 inches in red clay using a modded GP detector with a 10 x 5 inch Coiltek mono coil, the control detector (standard) could not detect the target at all. One of the main goals with Minelab detectors has been to stabilize the threshold so that target signals are not hidden in the noise. A lot of the noise generated in the Extreme, GP-3000 and GP-3500 has more to do with the interaction between the power output stage and the receiver stage. We can reduce the threshold warble so that the detector is rock solid stable! I have made quite a few video's on the Minelab pulse induction detectors, have a look at my YouTube video's at, Why woodypoopoo ? when I was trying to register an account everything I tried was taken, out of frustration I typed woodypoo and that was taken. So I typed woodypoopoo and it was available. So now I am stuck with it as YouTube will not allow me to change it. So I have to live with it. I may change it one day but that involves reloading the video's.

From the Goldfields of Thailand

The First Day.

This is a Gold Nugget from the Goldfields of Thailand, a generous prospector sent me this for doing some work on his SD-2100. He was getting a lot of Gold from his patch, 260 grams in one hole at 2' deep. This one is 12 grams. Thanks Paul.

This site is here to show you how to modify and carry out simple repairs on Minelab Metal Detectors. I offer a modification service for all the Minelab P.I detectors. The list of mods is growing all the time as we carry out different circuit changes to field test.
All the mods will definitely improve you chances of finding Gold Nuggets of all Sizes. There is NO detector available that can beat the depth on the modded detector!

Who Is Woody?

The beginning of time.

My real name is Peter. I have been running Link Technologies for 25 years. I've been an electronics Engineer for 28 years. Specializing in Radio Communications and Analogue systems. Design and development of everything from Tube audio amps to space based Satellite power amplifiers and low noise receivers. Now heavily into Minelab Pulse Induction metal detectors. Just completed a ground loop system, it can detect a Coke can sized object at 6.5 ft. Or over 2 Meters.