Whites detectors compared to others.

[user 4485]

Your link to a post made by "Jason" is not really accurate in what he says. The TDI doesn't work well with coils larger than 16" but the reason is the filtering characteristics. Keep in mind, it wasn't made to operate with larger coils.

The fact is, the TDI has more than enough power to run larger coils. Change the filtering and it is easy to display.

Thanks for the clarification Reg.
There was a discussion on here previously where a member had tried I think a 16" Coiltek coil & from memory it didn't work too well so he went back to a 14" x 9" coil. That discussion & the post I linked to above by "Jason" along with Miner John only having a 14" round as the largest available coil convinced me that larger coils weren't optimal. If theres a trick to settings or an easy mod than I'm sure more than one TDI user on here would be interested.
When you say "change the filtering" is that via the accessible ground balance controls etc. or internally? If internally how easy is it for the average detectorist with limited electronics experience to change the filtering & how would that affect other things like EMI, running in hot ground etc.

 

[Reg]

There are three different circuits that each has an effect that could be changed, depending upon what a person intends to do with the detector. Each one of these circuits have filter capacitors that could be changed.

The problem with change is, for every action there is a reaction. So, when one tries to change one thing, they will cause other problems or at least differences that may not be wanted.

Only the TDI Pro is sold in OZ, but the regular TDI would work also. The difference between the two models is not that great. One difference is the integrator rate speed which simply makes the Pro react a little faster to small gold signals. Since the SPP, SL and the regular TDI all have relatively the same integrator speed, they could be modified to work more like the Pro. Now, the integrator caps are simply part of a low pass filter design used to smooth out signals and help with reducing noise. Change them on the SPP and you may hear a little more noise but have the detector respond more reliably to small gold, especially if the operator is sweeping too fast.

Changing this circuit so the integrator is basically the same speed as the Pro requires changing two simple capacitors. The replacements really should be matched to 1%, though.

This integrator interacts with the next stage, the auto tune circuitry making it impossible to sweep fast and not lose small gold signals. This is why it is recommended one sweep slowly for best results. To test what you have now, take a small nugget, maybe a couple of grain piece of gold that is clearly detectable and check the ability to detect this small nugget at a depth of an inch or two. Now, bury the small nugget to the point where it is just heard and test the detection using different sweep speeds. It will become very obvious how easy it is to miss the small gold if the sweep speed is too fast. Cutting the cap value in half, from .47uf to .22 uf on the SPP helps. This change also reduces the interaction between the integrator and the next stage, the autotune circuit.

The autotune circuitry limits the size of coil that works best. It also makes the design very responsive and easy to signal lag. Take a ML PI and go over a large strong signal and that signal will last for quite some time. Any targets close can easily be missed because of the lingering audio response. Listen to a ML and you will hear a WEE-WOO or a WOO-WEE type signal. On big strong signals, both the WEE and the WOO last a long time. If you are walking than a fair amount of ground can be covered while the signals are still active. That area is not properly scanned for other signals.

On any TDI series detector, you will only hear a WEE or a WOO, but not the double signal. The second half is electronically cut off to assure the detection of signals close together.

Could a person change the caps? Yes, but I don't recommend it done by an amateur. One should always use quality grounded soldering and desoldering equipment plus good techniques.

Now, if a person wanted to slow down the autotune speed which would allow using larger coils on the TDI, then the autotune circuitry filters would have to be changed or made adjustable. One way to do this is add more capacitance. This would slow things down and create the problem of missing ground that occurs when using the ML.

Reg

 

[Ridge Runner]

There is a lot of brand loyalty when it comes to detectors. To put things into perspective WalnLiz who is a very respected member on here, returned from a WA trip a while ago after trying a TDI PRO OZ alongside his trusty GPX5000. His conclusion was that he missed little if any gold with the TDI. I think a bit of knowledge evens the playing field a bit between detectors.

Heres the post:

Combination of the GPX 5000 i'm using and the TDI Pro Oz that Liz is using. Let me assure you that the TDI is more than pulling it's weight and Liz has spent only 30 hours detecting for a total of 28 nuggets. That equates to almost a nugget an hour... Not to be scoffed at. She has followed me testing soft targets with my 5000 and has picked up almost all of the targets with the TDI. She actually picked up 3 nuggets in a gully that i missed with the 5000 an a mate also missed with the 4500.

On the right settings, you won't miss much gold.

Cheers,
Wal

Be interesting to hear which one would be packed if only one could be taken?
Not sure how the TDI would go with an 18" or bigger coil patch hunting?

From what I understand the TDI doesn't run the larger coils that well,maybe with correct setting it might be ok, but I'd be interested to know how it would go if there was a MJ or RB coil of that size made just for the Whites machines, like the NF & Coilteks are made for ML's.

Well don't tell the boss at gold search about not running big coils on the TDI, because someone just before Christmas found a 5 ozt nugget at 32" using the TDI and a 20" Nugget Finder Coil,

Now Whites/Reg/Luke fixed the hiccup issue the TDI's Whites has now corrected any problems they did have and they now see gold just as small as the SDC and being able to find deeper gold too along with there being over 100 coils to fit them puts the SPP in the lead, In fact in some cases they see smaller Gold and the TDI's can Disc out junk at Full Depth unlike Any VLF, and they work near power lines and Cell Towers and even in the City If Needed at maximum Gain, no other PI's can do that And they Can and Do Disc out rubbish which is a bonus for beach use, The ATX is not quite as deep but not far behind it, and the TDI Pro is equal to the GP3000/3500 as in depth some owners of both machine go as far to say the 5000 but I am not to sure about that but there again I don't see the 5k as a threat neither because the Pro has other talents like No being bothered by EMI So in bad areas where the 5k has to be turned down to get it to run, Where the TDIs work at full speed ahead,
Having owned Both I think the TDI is a more useable machine And for other Tasks where the GP/GPX's have very limited use then there is only one choice,

As For VLF's again I would go with Whites having owned 4 or 5 minelab vlfs, Whites run rings around them, I can tell what things are 90% of the time before I dig them, yes there are other fancy machines out there, But the MXT is the VLF version of the Toyota Land Cruiser of the Detecting world, It is Tough and it will do the job and they will still be a force to be reckoned with in years to come and is the highest selling machine to date, The reason they work so well is because they had the best Engineers and prospectors to build and field test them and The MXT was Built based on what the Prospectors Asked for and Not what the Company was Prepared to Build, It was made by prospectors for prospectors, and it is Not a Clone of past or present Technology, The whole thing is built upon it's own merit, and they field tested them in the hottest and coldest places on Earth in all Types of Weather, and they work in 99% of the gold baring places on the Planet.

Nower days The more junk and useless things they build in to detectors the more problems people have with them, with some of these machines before you buy them you need to decide whether you want to spend your time Programming them or just go detecting, and then you have try and get that right and when people don't find anything you will find them here asking for help because the Manuals give common controls fancy names and they do not tell you what the cause and effect is, If such things were put in plain English people might get on a lot better with them, Instead of owning a machine for a year and a half and then coming here Asking for help,

With LF machines I would go with the GMT for a couple of reasons because it has the best tracking system out there and it can see extremely fine Gold and with the right Coil it will match the Gold Bug II and it also goes deeper then the Gold Bug II with the bonus of having a meter showing Iron ID and having Tone Iron ID and also being able to follow the black sand makes it the best machine for Gold exploration if you are trying to find the Hot spots to set up your dry washer etc, and upon it's released the GMT Started a new Gold Rush in many places around the world,

Messing around with programs cause's many people to go out finding nothing and trying to make sense of such jargon out in the bush would be a big part for many good machines finding their way to Ebay, No to mention some of the Stupid Technology built in to these machines,

John

 

[Solid Luck]

I've got the SPP and I have found plenty of junk with it.
So I'm confident that when I walk over the gold it will find it.

 

[Ridge Runner]

I've got the SPP and I have found plenty of junk with it.
So I'm confident that when I walk over the gold it will find it.

Well I am sure too, that machine allows you to get on with prospecting and not have to worry if you have the right settings and the bigger the gold the Deeper your machine will go, getting away from computers is part of the reason we head Bush and then they go and stick them in to detectors and that is why people spend a year and a half trying to learn a machine and still end up struggling, your machine does away with that,, happy Days

 

[user 4485]

There are three different circuits that each has an effect that could be changed, depending upon what a person intends to do with the detector. Each one of these circuits have filter capacitors that could be changed.

The problem with change is, for every action there is a reaction. So, when one tries to change one thing, they will cause other problems or at least differences that may not be wanted.

Only the TDI Pro is sold in OZ, but the regular TDI would work also. The difference between the two models is not that great. One difference is the integrator rate speed which simply makes the Pro react a little faster to small gold signals. Since the SPP, SL and the regular TDI all have relatively the same integrator speed, they could be modified to work more like the Pro. Now, the integrator caps are simply part of a low pass filter design used to smooth out signals and help with reducing noise. Change them on the SPP and you may hear a little more noise but have the detector respond more reliably to small gold, especially if the operator is sweeping too fast.

Changing this circuit so the integrator is basically the same speed as the Pro requires changing two simple capacitors. The replacements really should be matched to 1%, though.

This integrator interacts with the next stage, the auto tune circuitry making it impossible to sweep fast and not lose small gold signals. This is why it is recommended one sweep slowly for best results. To test what you have now, take a small nugget, maybe a couple of grain piece of gold that is clearly detectable and check the ability to detect this small nugget at a depth of an inch or two. Now, bury the small nugget to the point where it is just heard and test the detection using different sweep speeds. It will become very obvious how easy it is to miss the small gold if the sweep speed is too fast. Cutting the cap value in half, from .47uf to .22 uf on the SPP helps. This change also reduces the interaction between the integrator and the next stage, the autotune circuit.

The autotune circuitry limits the size of coil that works best. It also makes the design very responsive and easy to signal lag. Take a ML PI and go over a large strong signal and that signal will last for quite some time. Any targets close can easily be missed because of the lingering audio response. Listen to a ML and you will hear a WEE-WOO or a WOO-WEE type signal. On big strong signals, both the WEE and the WOO last a long time. If you are walking than a fair amount of ground can be covered while the signals are still active. That area is not properly scanned for other signals.

On any TDI series detector, you will only hear a WEE or a WOO, but not the double signal. The second half is electronically cut off to assure the detection of signals close together.

Could a person change the caps? Yes, but I don't recommend it done by an amateur. One should always use quality grounded soldering and desoldering equipment plus good techniques.

Now, if a person wanted to slow down the autotune speed which would allow using larger coils on the TDI, then the autotune circuitry filters would have to be changed or made adjustable. One way to do this is add more capacitance. This would slow things down and create the problem of missing ground that occurs when using the ML.

Reg

So put basically the average bloke that walks into Goldsearch Australia & buys a TDI wouldn't be able to change the filtering for bigger coils/more power?
Whites should have you as their Lead Technical Development & Research guru. I know it's been said before but you could write a book on the TDI - only problem is blokes like me wouldn't understand half of it

 

[Ridge Runner]

Lol, from what I last heard the mods were being done at the factory, There is no perfect machine but some do come close, If I was needing Raw Power then The 5k would be the weapon of choice,

I am pretty sure someone with your skills would get on just fine with any machine, lol

 

[user 4485]

Well don't tell the boss at gold search about not running big coils on the TDI, because someone just before Christmas found a 5 ozt nugget at 32" using the TDI and a 20" Nugget Finder Coil,

Now Whites/Reg/Luke fixed the hiccup issue the TDI's Whites has now corrected any problems they did have and they now see gold just as small as the SDC and being able to find deeper gold too

Is there a link to that find or story? Not on their finds page. Bet theres some TDI users that would love to see that not to mention the rest of us. Nice chunk!

I always thought that the "hiccup" was only an issue on the SPP (or SL if purchased in) on some areas only & not an issue with the TDI pro at all? I know Reg & Luke came up with the fix, Whites should commend both of them - to me it seemed a thorn in their side (Whites - not Reg or Luke).
I'm interested to know what issues were fixed by Whites & when (are current models in Australia the improved version & if not will Whites fix these?) to improve the TDI sensitivity & depth as I didn't think the "hiccup" was related to either? I have seen somewhere else where this was raised I.e. somebody thought Whites had made some improvements to the TDI series but the general consesus was that they hadn't & Whites would neither confirm or deny it which didn't make sense. Good business sense says if you improve your product you advertise the fact? Lukes modded machine definitely had some good sensitivity - are these mods part of the fix & now standard?
My understanding was that the TDI SL still may not even have the "hiccup" mod done if ordered in now as it's a "special order" to get into Australia. I've seen conflicting info with some saying it's being done but others saying it isn't because the target market in the US don't get the issue.
Maybe Reg knows & can elaborate on both counts?

 

[Ridge Runner]

Well I read a post on the weekend that Whites were doing the upgrades before they left the factory, about 6 months ago I spoke to Whites in Scotland and they had no Idea what I was talking about, but Whites UK do not build the machines they are the importers and they do repairs, and as far as the hiccup was concerned they said they had never heard of it,

I think Reg got a bad deal, and both he and Luke made a huge effort to make them right and the end result was way more than what was expected, the silly part about it Australia is the only place where this problem showed it's self, I would of thought that like the original TDI the SPPs should have been tested there considering Australia Contains the worst HOT ground for detectors,

The story came Via an Email I got few months back,

 

[Guest]

Just a little to the side on that count; the SL that came from Arizona for me did in fact have the hiccup. I went out and did a few things Ridge-Runner told me to do and sure enough, there it was.

Anyway the SL is on its way to get the mod done. And for a price one seventh of the cost, of what a particular agent, for a particular brand of detector, in Victoria quoted me. WTF!

Sorry guys, as you know I don't get it. Maybe I should change my name to, I don't get it!

Anyway, look, guys, thanks so much for all this stuff you get up here. My detecting life has gone ahead in leaps and bounds. Plus I just got permission to have practically exclusive access to nearly twelve thousand acres up near Monto. It happened when I was out giving the SL a trot and a guy who knows this lady gave me her number and when I rang her she was like, 'Well, when are you coming up to have a look around?' Wow. She's a great lady. Top attitude.

Anyway guys, thank you for so much great direction and advice.

 

[Ridge Runner]

Just a little to the side on that count; the SL that came from Arizona for me did in fact have the hiccup. I went out and did a few things Ridge-Runner told me to do and sure enough, there it was.

Anyway the SL is on its way to get the mod done. And for a price one seventh of the cost, of what a particular agent, for a particular brand of detector, in Victoria quoted me. WTF!

Sorry guys, as you know I don't get it. Maybe I should change my name to, I don't get it!

Anyway, look, guys, thanks so much for all this stuff you get up here. My detecting life has gone ahead in leaps and bounds. Plus I just got permission to have practically exclusive access to nearly twelve thousand acres up near Monto. It happened when I was out giving the SL a trot and a guy who knows this lady gave me her number and when I rang her she was like, 'Well, when are you coming up to have a look around?' Wow. She's a great lady. Top attitude.

Anyway guys, thank you for so much great direction and advice.

The mod has only been done to this years models so yours and mine would not have been done but I am not worried because my new PI machine will be here in the morning and if the SL bothers me I will get it fixed if and when,

I am glad the tests worked out for you, Now your machine will see very Tiny Gold and they run quieter than the SPP anyway even when turned up to 10 where the SPP has a pre set mark of around 5 not that that matters, They all run quiet, just grab that miner john 5x9 folded mono coil and the 8x14?? I think that is the size because they make slightly different sized ones for minelab machines.

Good Luck mate and let us know how it works out, ok

john

 

[ozziii]

Thanks very much everyone, its interesting to read about the different machines & how they perform etc. This extra info has been very helpful for someone pretty new to detecting & I'm sure others will also find it helpful.
I'll have to read it all again just so it sinks in a bit better though I think,haha.
Glad we should be getting some decent weather soon, I'll be out as much as I can with the SPP learning how to get the best from it, specially once we get the RB folded mono coil, shouldn't be too long now.

Thanks again.

 

[Ridge Runner]

Thanks very much everyone, its interesting to read about the different machines & how they perform etc. This extra info has been very helpful for someone pretty new to detecting & I'm sure others will also find it helpful.
I'll have to read it all again just so it sinks in a bit better though I think,haha.
Glad we should be getting some decent weather soon, I'll be out as much as I can with the SPP learning how to get the best from it, specially once we get the RB folded mono coil, shouldn't be too long now.

Thanks again.

Your welcome, just go out and enjoy ya self, your machine has had the mods done I think?? so you will hit the ground running, get those coils and its just a matter of putting the coil over the Gold,

I Tested the Whites 7.5 coil and I am sure it has the same depth as the 12" coil but it is better in tight spaces I don't think it see's the smaller nuggets that the MJ coils do, another thing to remember is if you use the standard coils (12" and the 7.5") use a solid coil cover on them, then they don't get hung up on things, ok.

Good luck,

John

 

[Reg]

"The autotune circuitry limits the size of coil that works best. " Now, this doesn't mean large coils won't work. In fact, Jimmy Sierra sells one that is a 20" coil for those of you interested in large coils. Also, I was told it will work on the SPP.

http://jimmysierra.com/sierragrandeloop.html

What happens when you use a real large coil is the autotune feature will cause a noticeable depth loss, especially on small objects when trying to sweep slowly. So, the trick in using a larger coil on the TDI series is to sweep faster. Use a smaller coil like a 8" by 12" folded mono and maximum depth on small gold is enhanced by sweeping slower.
The key is to find the ideal speed on any coil used plus know what is lost and what is gained.

Reg

 

[Guest]

Just a little to the side on that count; the SL that came from Arizona for me did in fact have the hiccup. I went out and did a few things Ridge-Runner told me to do and sure enough, there it was.

Anyway the SL is on its way to get the mod done. And for a price one seventh of the cost, of what a particular agent, for a particular brand of detector, in Victoria quoted me. WTF!

Sorry guys, as you know I don't get it. Maybe I should change my name to, I don't get it!

Anyway, look, guys, thanks so much for all this stuff you get up here. My detecting life has gone ahead in leaps and bounds. Plus I just got permission to have practically exclusive access to nearly twelve thousand acres up near Monto. It happened when I was out giving the SL a trot and a guy who knows this lady gave me her number and when I rang her she was like, 'Well, when are you coming up to have a look around?' Wow. She's a great lady. Top attitude.

Anyway guys, thank you for so much great direction and advice.

The mod has only been done to this years models so yours and mine would not have been done but I am not worried because my new PI machine will be here in the morning and if the SL bothers me I will get it fixed if and when,

I am glad the tests worked out for you, Now your machine will see very Tiny Gold and they run quieter than the SPP anyway even when turned up to 10 where the SPP has a pre set mark of around 5 not that that matters, They all run quiet, just grab that miner john 5x9 folded mono coil and the 8x14?? I think that is the size because they make slightly different sized ones for minelab machines.

Good Luck mate and let us know how it works out, ok

john

Yes, the MJ or the RB. I was speaking with Brian about it and as soon as I start bringing in some pay-dirt, I'll be shifting up to one of those.

 

[ozziii]

Thanks very much everyone, its interesting to read about the different machines & how they perform etc. This extra info has been very helpful for someone pretty new to detecting & I'm sure others will also find it helpful.
I'll have to read it all again just so it sinks in a bit better though I think,haha.
Glad we should be getting some decent weather soon, I'll be out as much as I can with the SPP learning how to get the best from it, specially once we get the RB folded mono coil, shouldn't be too long now.

Thanks again.

Your welcome, just go out and enjoy ya self, your machine has had the mods done I think?? so you will hit the ground running, get those coils and its just a matter of putting the coil over the Gold,

I Tested the Whites 7.5 coil and I am sure it has the same depth as the 12" coil but it is better in tight spaces I don't think it see's the smaller nuggets that the MJ coils do, another thing to remember is if you use the standard coils (12" and the 7.5") use a solid coil cover on them, then they don't get hung up on things, ok.

Good luck,

John

When I spoke to Brian he was saying the RB 7.5x11 folded mono was pretty good on small gold, as good as, if not better than the NF 6x8 Sadie when on the SPP, & it also has much better depth. He also mentioned how this is the coil he uses 90% of the time.
The folded mono's get slightly less depth than a normal mono does though, but not a very large amount.

 

[Reg]

First, I need to mention a couple of things with one being a folded mono should get a little more depth than a plain mono of the same size. Why? Well, the answer lies in the fact the folded mono is a larger coil folded into a smaller coil. Thus, the extra field should enhance what is there. Because of its physical design, a folded mono is limited in size. A dual field can be made bigger.

As for changing capacitors to make large coils work better, well, doing so reduces the sharpness of the signal you get on small gold now. So, making the addition of more capacitance permanent, that reduces the action of the present design. Ok, fine, then add the extra capacitance with a switch so it can be switched in or out. Well, that doesn't work that well because switches and the associated leads are little antennae that can add lots of noise, so other tricks need to be done. Once the ideas are perfected, then adding caps may be a reality without adding noise.

So, there may be new features in the future.

Reg

 

[Magilla]

Thanks for sharing your knowledge Reg, it is very appreciated mate.

I do have a question for you that I have been unable to get any opinions on from any source. Do you think the new NF and Coiltek coils that have just been released would show an improvement over a coil like the Sadie when used on the TDI Pro OZ?

 

[ProspectorPete]

Hi guys, I've been laying low for a while due to a busy time at work/home lately and haven't been prospecting or even visited the forum much of late but have just read this thread with interest regarding bigger coils on the Whites detectors.
I bought my SL new locally from an ex member to the forum and he did the hiccup mod before I bought it, I also bought a brand new Jimmy Sierra Grande 20" coil (black) from the same person who happened to had 2 of them as a custom order re-badged as Minor John.

Anyway, I tried it out before I bought the coil in very hot ground in the Maryborough area on a stormy day and apart from the coil over balancing the detector it ran very well with the pulse delay on 20 and HIGH conductivity the only issue I had was it would "scream" when I swung from left to right at the end of the swing, I soon realised I had my keys in my right pocket and this was setting off the coil.
We also air tested with a 2oz lead sinker I had in the back of my ute, sinker placed on the hot ground we managed to get a solid signal at about 3 foot.
I'm pretty confident this coil on my SL with the right settings will pick up a decent nugget at depth of 2ft no problems which is why I chose to buy it, I have since bought an extra extended leg to get the coil away from my feet and a harness, bungy, control arm to better balanced the set up when I choose to go nugget hunting in the right conditions.
Although the coil may only get used once every 1-2 years or 5% of my detecting time it gives me options which is something I like to have.

Anyway, that's my take on the large coils for the Whites detector, although I've only used it once it seems to work on this machine and can't wait for the opportunity to get back out and spend some serious time with it hunting for bigger nuggets.

 

[ProspectorPete]

Oh, and I forgot to mention that I had been out detecting with the small coils a few times (9x5 folded mono & 11x7 mono) but in the back of my mind wondered if I should have bought a ML so I could run bigger coils and find more gold like the ML users seem to well at, I now feel with this new set up and the RnB 3100 mah battery pack I'm in an even playing field to the ML guys, in fact if I was smart and really only worked the hi EMI areas where the ML's struggle I believe this would put me ahead of the ML's.
I just need to get out and put some hours in to prove that theory, the other reason you see a lot more ML posts of gold finds is there is a lot more people here using them.
The 2 reasons I bought the Whites is:

1. Price, I'm only new to prospecting and it's a part time hobby at best.

2. Weight factor, I'm reasonably light framed and after some serious neck surgery over the past few years I struggle to do certain things for long periods of time.

End result was a no brainer, for me!!

Cheers.