Whites Spp Coil Question

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ikaruz

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Hi, so... i bought a secondhand whites spp, i'm still waiting for it to arrive at my house. i was looking to buy a extra coil. i have got a xp deus 2, and i'm looking for a deeper detector, the dream was minelab gpx, but too expensive... I read some reviews of this machine, and it seemed like a good choice. i'm from europe, so almost every coil that I read were good, I just can't find them here in Europe. i have two options, or a minelab coil, or a detech coil. i was looking at the detech coils, and i found this "DETECH 18" MONOLOOP CLOSED DESIGN SEARCH COIL FOR MINELAB GPX, GP, SD SERIES GOLD DETECTORS WITH COIL COVER PROTECTOR INCLUDED", so... will this coil work great at this detector? have anyone tried it? is it stable? this coil is compatible with "This Detech 18″ Monoloop Closed Design Search Coil for is for use with Minelab GPX, GP, SD and White's TDI/TDI Pro/TDI SL Series Metal Detectors."

so... is this coil a good option? or which coil do you recomend between detech or minelab compatible with this detector?

thanks
 
Why do you want such a big coil as this 18” Detech mono.
You will find this coil is very heavy on the SPP detector and it will feel unbalanced. If you need to go for deep targets, then the 18” Detech concentric coil would be a better option. It is an open design, so much lighter.
The SPP would also benefit from a battery modification to increase voltage of the factory pack to take advantage of the bigger coil.
Other great options for Whites TDI machines are American made Razorback coils..... if you can find them.
 
OzzieAu said:
Why do you want such a big coil as this 18” Detech mono.
You will find this coil is very heavy on the SPP detector and it will feel unbalanced. If you need to go for deep targets, then the 18” Detech concentric coil would be a better option. It is an open design, so much lighter.
The SPP would also benefit from a battery modification to increase voltage of the factory pack to take advantage of the bigger coil.
Other great options for Whites TDI machines are American made Razorback coils..... if you can find them.
Click to expand...
i want to go deeper, to get some coins and artifacts at open field at the area that other detectors cant go... i already tried xp deus, xp deus 2, minelab ctx, and a few more, now i want to try the power of pulse induction, the detector came with a coil of 11" or 12" i think, so i want to try a larger coil. i like to try new detectors.

about the detech concenttric coil, is almost 100€ more expensive, and at the description they only say minelab gpx, and not the whites...
 
ikaruz said:
i want to go deeper, to get some coins and artifacts at open field at the area that other detectors cant go... i already tried xp deus, xp deus 2, minelab ctx, and a few more, now i want to try the power of pulse induction, the detector came with a coil of 11" or 12" i think, so i want to try a larger coil. i like to try new detectors.
Click to expand...
The SPP was White's most dumbed-down version of their TDI platform. Given it's relative lack of power and non-adjustable pulse timing, it is unlikely to offer better depth than the VLF detectors that you have previously tried, especially since it probably lacks the grunt to work well with bigger coils as you propose to do.

The TDI Pro is the Whites model you should have bought, although it probably offers no advantage over older model Minelabs, if maximum penetrating power is the aim.
 
The 18” Detech concentric (for gpx) will run on the SPP as I have tried it on mine before I sold both.
As grubstake has said, the SPP lacks the power to push a big coil for any significant depth advantage. A battery pack upgrade to increase the voltage to around 14 volts could help to increase the potential of a bigger coil.
I did find that the concentric coil was very stable.
 
SPP has a fixed 10us delay. I am surprised an 18 is able to successfully run on it

A few years ago I tried a older brown bundle wound solid Detech mono 18" on my SL and it needed +12us to work ( i think 15us was ok).

unimpressed with weight or performance so got rid of it.

16v is the go !
 
grubstake said:
The SPP was White's most dumbed-down version of their TDI platform. Given it's relative lack of power and non-adjustable pulse timing, it is unlikely to offer better depth than the VLF detectors that you have previously tried, especially since it probably lacks the grunt to work well with bigger coils as you propose to do.

The TDI Pro is the Whites model you should have bought, although it probably offers no advantage over older model Minelabs, if maximum penetrating power is the aim.
Click to expand...
oh.... ok... thanks for your answer.... i was looking for a whites tdi sl pro, i was looking probably for a year or more, but didnt find any at ebay (europe) and online stores... i saw this spp and bought it.
 
OzzieAu said:
The 18” Detech concentric (for gpx) will run on the SPP as I have tried it on mine before I sold both.
As grubstake has said, the SPP lacks the power to push a big coil for any significant depth advantage. A battery pack upgrade to increase the voltage to around 14 volts could help to increase the potential of a bigger coil.
I did find that the concentric coil was very stable.
Click to expand...
thanks, i need to check that battery upgrade. i think is the way to go!
 
XLOOX said:
SPP has a fixed 10us delay. I am surprised an 18 is able to successfully run on it

A few years ago I tried a older brown bundle wound solid Detech mono 18" on my SL and it needed +12us to work ( i think 15us was ok).

unimpressed with weight or performance so got rid of it.

16v is the go !
Click to expand...
thanks!
 
TDI Pro can use the Detech 18/8" concentric coil wired as a DD or a 18" mono.
In beach picture used with TDI Pro it's wired as a DD.
TDI SL and SPP both have a socket for Pulse Delay.
Just fit the right value pot and wire it up on the SPP.
 

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nesral said:
TDI Pro can use the Detech 18/8" concentric coil wired as a DD or a 18" mono.
In beach picture used with TDI Pro it's wired as a DD.
TDI SL and SPP both have a socket for Pulse Delay.
Just fit the right value pot and wire it up on the SPP.
Click to expand...
hi, thanks for your answer, i already saw a mod for the condutivity mode, for example this: https://www.prospectingaustralia.com/threads/spp-conductivity-switch-pre-made-crimp-leads.13934/

but i didnt saw any mod for the pulse delay, do you have a link? or a feedback of that? i know that the spp board have that socket, but i didnt find anyone doing that change...
 
Pulse Induction works by sending a pulse and trying to detect the eddy current voltage that occurs in the target when the pulse is shut off. You cant detect the target immediately after coil shutoff as there is a big voltage spike so you have to delay the sample period a few micro seconds. Unfortunately the target eddy current also decays in a matter of 10us-12us for small low conductivity targets like tiny nuggets. For more conductive and bigger targets ( coin size & above) larger delays can be used - 25us is fine for coins & for big silver items even 100us. The ground has a fast decay (~4us) but mineralised or wet salty ground can be longer - enough to interfere with short delay periods. Also the bigger the coil the longer the flyback spike lasts so it interferes more when you have a short delay period. Different coils even of same size wll have different decay characteristics depending on the wire used & number of turns & type of winding.

I guess what I am saying with all that electro-mumbo-jumbo is that for coins you not only dont need a small delay but you are better off with a longer delay as you will see deeper in mineralised ground & can use bigger coils so you will see deeper in all grounds.

This is inside my TDI SL. You can see the delay pot with the red dot - it is 100kOhm. I cant remember if log or linear but doesnt make any diff. You can also see the plug with the red mark. this is where the pot plugs into the board. The board is marked "Pulse Delay" & has 3 holes for pot wires. I dont know where your fixed resistor is in the SPP but you should be able to see it by following the track from where the pot goes. Remove the resistor & install the pot

Any coil designed for a Minelab GP-GPX will plug straight in to any Whites TDI series detector & will be compatible but for an SPP there is the caveat on size due to fixed delay.

Suggest just buying a second hand ML GPX compatible coil and trying it out 1st to see see if you are happy with the depth increase. Frankly, in non mineralised ground a VLF & PI with same size coils should give similar performance, the main benefit of PI being that non ferrous targets wont be masked by nearby ferrous targets.
 

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Last edited:
ikaruz said:
hi, thanks for your answer, i already saw a mod for the condutivity mode, for example this: https://www.prospectingaustralia.com/threads/spp-conductivity-switch-pre-made-crimp-leads.13934/

but i didnt saw any mod for the pulse delay, do you have a link? or a feedback of that? i know that the spp board have that socket, but i didnt find anyone doing that change...
Click to expand...
My modifications to the SPP was aimed at increasing the sensitivity to small low conductors like tiny gold pickers and very fine jewellery when beach hunting. . . . . This aim was achieved.
Larger coils I mainly use on the TDI Pro.
 
Hi, so the detector finaly arrived today. i dissassembled it, at the board it say "GMT super pulse", what i read in several forums is that this detector has a whites tdi sl motherboard, so my question is, this gmt super pulse motherboard is the same of a tdi sl? what the differences of tdi sl and gmt super pulse? thanks
 
mbasko said:
A sticker on the control box.
TDI SL - US, Aust markets
GMT Super Pulse - African markets
Click to expand...
thanks for the answer, the pulse delay will work if i connect there a connector? or the detector is modified by software? thanks
 
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