The GPX 4500 - General Opinion

This is the new top of the range detector in 2008, and from the sounds of it, one of the most popular. What makes it so successful? They talk abouts its depth - what settings should you use for that?

You cant buy experience, so share your experience here so we can all benefit from each other

These machines ROCK !!!

TM

I'll stick my neck out and say that the 4500 is, without doubt, the best Minelab detector I have had the pleasure of operating. The multitude of controls allows the operator to finetune the detector to suit their preferences and the ground. I also believe that there are very few settings that will cost a lot of performance if selected wrongly, and like most other GP series of detectors, running a mono coil in cancel mode is one of those settings, although there is an advantage of using that combination if the signal is that large that you cannot get close enough to pinpoint it. I have used that combination several times in the past as have some of my mates for exactly that reason.

Pretty much most of the combinations of settings will give a decent response on most targets though the skill level comes down to the operator having enough experience to choose the ones most suited to the situation/coil/groundtype/gold size/interference level. Don't be afraid to experiment and the best time to do that is on a target that you think might just be a good yellow one. Good hunting.

I agree the 4500 is a very good machine

cheers dave

Hi all,
no denying it, the 4500 is a killer machine when its running smooth and the EM interference is low. Proof in point:
borrowed one for 4 hours recently, went to a flogged spot of mine, 14 pieces for 5gm. Used a crappy old Minelab mono 11" too! Was impressed with its performance before (when I used a good one!), but even more now. Not impressed with the price though Cheers, Dwt

Santa can I have one of these for christmas.

Ed.

In spite of all the nonsense you sometimes read on the net it's nice to see Minelab continue to refine their products to the point where they offer real time performance gains over the previous models. Its a shame that one has to think about ducking for cover every time something positive is said about a great Aussie innovator . I'm proud to be Australian and doubly proud to be swinging a Minelab and why not my pocket benefits at the same time I get to feel all warm and fuzzy.

JP

About the GPX 4500:

• IMPROVED DISCRIMINATION: gives you access to the worst of trashy ground. When detecting in a high-trash area like a mining site or a campground, the Iron Reject function allows the operator to set the desired level of discrimination, from cautious to aggressive. This will assist detecting in areas that have previously been rejected due to the quantity of Ferrous junk.

I do not have a GPX 4500. But for those who have one, how is both the depth and quality of this improved discrimination to find gold nuggets in high-trash goldfeilds on a scale of 1 to 10??

(Is it of poor quality and just about useless like on the SD and GP series??)

Thank you.

The discrimination is simplified over previous models, so changes in one number to another are more aggressive. Personally I rarely use the discrim and more so now the 4500s are more Mono friendly.

JP

Gday Beer Beeper
I've tried the descrim on my 4500 a few times on some very messy sites where I know there should be gold, but the old guys lived over them.
The descrim is virtually useless.
cheers
Brett

There are too many variables for mine to use a discriminator on a PI machine. It has been mentioned time and time again over the various forums and the consensus is that a PI discriminator is only usefull on close to surface trash, and bigger trash at that. DIG all targets.

Agree with Sandy... I couldn't remember the last time I used discrimination, dig every target and recheck the hole after you've found it.
About 4 weeks ago I dug a horse shoe nail just below the surface, jumped out onto my magnet. On rechecking the hole I got another only just audible signal just off to the side which was a nice little 2 grm nugget. Had I used discrimination and rejected the nail I highly doubt I would have heard the nugget.

As for the 4500 itself, I'm disgustingly impressed! The smooth threshhold is just a joy to work with hour on end.

As someone above said, dont be afraid to experiment with the different settings..preferably on a signal that is gold.
For starters though, the factory presets WILL find you gold, watch JP's DVD that comes with the 4500 a bunch of times and follow his reccommendations. Don't be afraid to play about with different combinations..you wont hurt it and can always hold down the power switch to get back to the factory presets if needed.

This is my second 4500 as my first was a straight swap over due to the recall and I cannot praise ML's warrenty, customer care and after sales service highly enough

It makes a refreshing change to hear some positive comments on the 4500, unlike the boring negatives on another Minelab hater's forum which will remain nameless...
Cheers
S

I think the reason why the GPX-4500 has been so popular is likely because there isn't another detector that exceeds it's abilities though other models do come close. Sure, some previous models can get similar depths with a DD coil, but this is the detector that allows the use of deeper seeking Mono-loop coils (something previous detectors had trouble with). And more depth certainly means more Gold - as long as digging deeper holes isn't a problem for you.

Some time ago, when the SD 2100 was the number one detector, Minelab released the 11" Monoloop Coil. A Minelab rep named John Gladdis (who was involved in the development of this coil) traveled around Australia and attended numerous gatherings where he tried to impress upon Prospectors that the Mono-Loop coil could penetrate deeper... and I suspect he was largely ignored because everyone knew that Monoloop coils were VERY noisy and hard (impossible in some areas) to work with on mineralized ground. But times have definitely changed... and the Monoloop is much quieter on the new GPX detectors on noisy ground when the new timings are used. Now the GPXs can penetrate noisy ground deeper than the older models by using the once-shunned Monoloop coils.

This is where the GPX-4500 shines. It can run quietly on ground that previously only gave up gold to shallower scanning Double-D coils. It also has more settings to be changed to allow the detector to be tweaked for a more personal experience. It also represents the refinement and eventual apex of features introduced by the SD/GP/GPX range.

I've now tried almost all the previous models and, in my opinion, the 4500 has more capability, sensitivity and depth (due to smoother use with a Mono). If a future model is released, I can't see a whole lot of room for improvement... so perhaps it will incorporate design changes rather than new capabilities. ANY detector will find Gold near or on the surface. But only an SD/GP/GPX can penetrate the mineralized soils on our Goldfields properly. And the deepest seeking coils are Monoloops although only the GPXs can use these coils in tough soils to maximum effect. I suspect that the 4500's will still be popular for a long time. Even if they're superseded some day.

As noted above, the discrimination on the PI detectors only operates on targets near the surface close to the coil. The discrimination area occupies less than one-sixth of the entire depth of the coil's emission field. If the depth of a coil's field were represented by your longest finger, the area where discrimination functions is a region the size of your fingernail. You still need to scrape away the topsoil first ...when using a DD coil to discriminate. Getting rid of the minerals deposited on the surface will then allow better discrimination. I will add that my own 4500 attempted to tell me a small 1.5" target I was about to dig at 2 feet was iron based so perhaps the discrimination varies depending on the soil - and you may get more depth depending on mineralization. The signal would blank out for a fraction of a second in mid sweep. Of course, I had to dig it. Bit disappointed on that one. But I really do love this detector.

So how do you think the 4000 compares to the 4500.
cj

CJ wrote:So how do you think the 4000 compares to the 4500.
cj

It's pretty close but I like a couple of features on the 4500 that are missing from the 4000. I think the new SETA timings give the 4500 an edge with noisy ground though. You flick the switch (to "Enhance") and immediately notice a quieter threshold on some of the worst types of ground as the new Timing stability kicks in. I've found the added backlight useful in low light a few times... but the built-in amp (in the battery) allows me to use a speaker without having to add a booster - it just plugs into the headphone jack and then clips onto your harness.

Ignore the above and the 4000 and the 4500 are one and the same to me.

nero_design wrote:

CJ wrote:So how do you think the 4000 compares to the 4500.
cj

It's pretty close but I like a couple of features on the 4500 that are missing from the 4000. I think the new SETA timings give the 4500 an edge with noisy ground though. You flick the switch (to "Enhance") and immediately notice a quieter threshold on some of the worst types of ground as the new Timing stability kicks in. I've found the added backlight useful in low light a few times... but the built-in amp (in the battery) allows me to use a speaker without having to add a booster - it just plugs into the headphone jack and then clips onto your harness.

Ignore the above and the 4000 and the 4500 are one and the same to me.

Was just wondering how long you have been using the 4500? please don't take this as a dig, but the underlined section above reads from an employee, not a 4500 user.

narrawa

"Ignore the above and the 4000 and the 4500 are one and the same to me."

I have both the GPX4000 & the GPX4500 they are certainly NOT one and the same to me.

cheers dave

Those were my own choice of words since this thread is about our own experiences with the 4500 and the differences between the new GPX and the old. I've used the 4500 since it was first released last year but obtained my own to avoid using someone elses. I spent a bit of time talking with my local supplier before concluding that this would be the detector of choice for me. ML heard i was arranging to buy one and were kind enough to make one available for me last year. I was a little surprised when the 4500 was announced because the 4000 didn't seem to have been out for all that long. The 4000 and the 4500 are certainly very similar but when you've used both detectors side by side, it becomes apparent that the extra features of the 4500 make it a more appealing and capable model. In my opinion, the depth and coil options of both models are the same.

The section you underlined is the main strength of the newer model. It's just much more stable with the SETA timings on noisy soil. More so than any other detector.

Well that's a fair enough answer i guess, but from your words about SETA it kinda looked as if you were a new chum, because there is not many that would give SETA the kinda rating you gave.
The underlining above would have to be the biggest disappointment in this model and im not alone when i say this because those of us who use the detector almost daily see a different outcome.

Enhance was what made this detector stand out because it was something the prospector could not argue with, unlike SETA that works away in the background unnoticed by the operator enhance was noticed as an improvement over sensitive smooth from the 4000.
Yes i would agree that the 4500 is the better of the two models, and having both 4500 & 4000 at my reach at anytime, and have done well with both in the time frame that they have been out know which one id prefure.

"The section you underlined is the main strength of the newer model. It's just much more stable with the SETA timings on noisy soil. More so than any other detector."

SETA from my understanding is not a timing, but an alignment of the timings.

I hope you don't feel as if im having a dig at you but from many of your posts i feel there is something missing, that being time on the ground, this you cant get from books, videos or the telephone.

Those were my own choice of words since this thread is about our own experiences with the 4500.

narrawa

SETA is a Narrawa suggests something that works in the background and I should point out (for all those who feel it is not of importance) that minelab won an award on the innovation of what SETA provides. Minelab website

The problem is Australia is suffering from some of the worst weather conditions in years and I think you will find that all detectorists are suffering from interference, something that SETA cannot deal with, the interference is mainly from lightening spikes that are generated thousands of kilometers away and unfortunately generates a response that sounds just like a target so there is no avoiding them SETA or no SETA. I also demonstrated a ground condition in our "GPX Factor" DVD that caused problems for the GPX-4000, that same ground condition no longer upsets the GPX-4500, that is SETA at work. I also demonstrated SETA at play in "The SETA Project" DVD where I compared both the 4000 and the 4500 on special magnets, that footage is well worth viewing as the differences are quite obvious.

The big differences between the two GPX machines is in more refinement with audio controls, SETA, two new timings of which Enhance would have to be the biggest leap forward and well and truly justifies the upgrade price along with the new inbuilt booster in the battery.

When going to Enhance the threshold can sometimes actually sound a little more unstable, this is because the vast majority of ground noise effect has been removed allowing the threshold to be more expressive of everything else (a little like the differences between a Mono and a D coil). In some instances the threshold becomes too unstable and Normal or some other timings has to be used, this is usually during periods of intense unstable weather patterns.

A digital platform is not an exact science and as such we should see improvements over time as things become more refined, this is the major differences between the 4000 and 4500.

JP

Post note to Alluvium: if there is no interference about then SETA does what it is supposed to. Obviously tilting your coil on noisy days is going to cause problems.