karelian

So what would I dream White's would add and change on the Tdi Sl. Interesting to see what direction others would like White's to go in.  

Not asking them to reinvent the whole system, just significant tweeks to breath new life into the Tdi machines.

1.Keep the light weight body. A well balanced detector that is super light and easy to swing all day.

2. Replace the mounting setup, like the old Tdi Pro, please use screws so I can hip mount the detector quickly and easily.

3. Keep using the same battery system, just upgrade to a 16 volt rechargeable, or 4 x 18650 system. Extra voltage matched with upgraded components etc Push the boundaries..

4. Retain the compatibility with MInelab coilts etc.

5. Upgrade the ground balance please, fine and course.. or a ten turn.... makes a big difference.

6. Yes I admit this sounds like a Tdi Pro in a smaller, lighter and better balanced rig. Only dreaming but far from impossible. Nothing mentioned here that has not been done by owners in the past as           modifications of existing White's machines.

I can live without hipmount on such a light and well balanced machine, I've already pushed the battery system to max, at 16 volts. I'll keep a lazy eye out for a solution to the ground balance knob, I've seen a two tier knob etc. Just dreaming.

I traded a small coil for the Jimmy Sierra Tdi Chest Harness, not using it but I'm heading in that direction for beach hunting in the 'wet zone'. Not safe to put the machine down so it makes good sense. Very hard to find new, impossible maybe, but there are a few floating around, mostly unused. Like almost everything else I use, I'll be looking at modifying it and doing a few custom additions. Not overly complex, simple design actually and easily replicated. All the best.

When looking at the  White's  rechargeable factory packs you cannot but be dissapointed. Barely adequate for stock Vlf machines and completely inadequate for the Tdi Sl.  We are forced to go elsewhere in search of voltage and depth.

I quickly tried the Rnb battery pack, it has three 18650  cells, max voltage is about 12.5. Great for my White's Vlf machines, not the

Tdi Sl. Moved on to try the disposable lithium cells, good voltage and decent improvement in performance. Cost was and is an issue.

Tried the 3 x 18650 Ukranian orange pack. Same as the RnB, just a lot cheaper. Use your own cells and charger. Great and used on all my White's  VLF machines now.

Finally ended up converting a battery tray and going with the 4 x 18650 rig. Loving it. End of the road.

Since I'm not going to risk a large fine by venturing 'out', this was a bit of fun. Hope I'm not the only one who has run a machine over my back yard and front lawn. Hot tip, use a small coil and check under the washing line.. 

When circumstance allow, I like to go prospecting in Victoria's 'Golden Triangle', one of Australia's nugget hot spots. I use my beach machines, a Tdi Pro and a Tdi Sl Limited Edition. The Pro can be used for prospecting without any real issues, the Tdi Sl is more challenging in this environment. I'm going to focus on my experiences in hot ground, infested with ironstone, hot rocks and heavy mineralization. Not going to focus on depth, power or anything other than what it takes to get the machine to operate smoothly with the correct ground balance. The Pro machine has a hugh advantage, simply by vitue of that course and fine ground balance adjustments but this post is mostly about the Tdi SL. The single turn ground balance on the SL is a pain, it takes a bit of time to get it just right.

When the ground is hot the SL requires me to use a smaller coil, mono being the best. Mono coils in my experience are quieter, more stable and much easier to ground balance. Larger folded mono coils, duel field coils and the newer and hotter spiral wound coils all suffer when the ground is very hot, they are noisy and difficult to ground balance with a Tdi Sl.  The Tdi Sl with the stock 12 x 7 Miner John folded mono can be balanced but it will transmit more ground noise and be more difficult to ground balance when compared to using a smaller mono coil. Forgive me but I'm going to repeat myself a few times in this post.

 The smaller the coil the quieter the Tdi Sl will be and easier to ground balance, the reduced 'foot print' helps a lot. The very small 6 x 4 mini Jimmy coil is amazing in its ability to run smoothly and easily ground balance, but is too small to be practical most of the time. In comparison I can use larger mono coils on the Tdi Pro without issue, it has superior ground balancing ability on the goldfields.  A Tdi Pro mounted with a 8x6 mono 'Sadie' is my standard setup. The Detech 15 x 10 or Digger 14 x 8 also see some use as does the new to me Detech 8 inch mono when using the Pro. So whilst the Tdi Sl likes the smaller mono coils on the goldfields the larger coils are not an option. Yes the ultimate Tdi Sl setup is a small mono coil and an upgraded 16v battery pack for prospecting. Super light weight and beautifully balanced, respectable performance and versatile. Fun to use for all, kids and older family enjoy the light weight and balance. 

Allow me to deviate for a moment. Tie me to an ants nest and smother me in honey for stating the obvious. Serious prospectors are better served by more specialised Minelab machines... they are superb.  For me versatility is key at the moment and  I feel better served by my White's Tdi Pro on the beach, that stealthy little Tdi Sl 'urban PI'  is also a pleasure to use. When I invest in an expensive 4x4 and trailer some time in the future, then I'll make room for the more specialised gold machine. Hopefully by then  Minelab with have a light weight and well balanced SDC type PI in a Tdi Sl style body. Maybe White's will surprise us all. Fisher is coming to the party also. I need PI peformance and light weight, good balance and sane pricing.. more options arriving as time goes on.

Again my one piece of advice to anyone wanting to prospect using a Tdi SL in 'hot' ground, particularly in Australia, is this.. Use a small mono coil. Small duelfield coils like the older Jimmy, 7.5 duelfield, Miner John 7x5 folded mono or 6 inch folded mono coils, are all OK most of the time.. The Razorback 10 x 6 mono is great, the Coiltek Tdi series 6 inch mono is great, The Sadie is great. Keep it small and stick with mono and you should do well in all types of ground. The larger coils work well with the Tdi Sl in moderate soils and the beach. But when the ground goes bad it does pay to swap out for a small mono.

Again this is my experience in hot Australian ground. Hot is hot and I suspect many international Tdi Sl users have the same experience in difficult ground. Not looking to pick any fights but this is my experience with the Tdi Sl. Go small, go mono and boost the battery pack. All the best.

That Super Pulse 220 mono coil uses the time proven 9.5 housing so common on earlier White's. So scuff plates are easy to replace and coil hardware is all White's. Performance on the Tdi Sl is good, particularly with the higher voltage battery pack. A great all rounder.  The small 6 x 4 Tdi coil is super easy to ground balance and super quiet on the hottest ground, but is so small I rarely use it. If you can find one, pretty rare are the White's 7.5 mono coils made for OZ, good for the goldfields but maybe a bit small for the beach?

Another option would be the Razorback 10 x 6 mono, super light weight, good performance and decent coverage. Not sure how it would work out hardwired on a Beachhunter, but in hot ground it would be easier to ground balance and operates a bit quieter and smoother.

Tony the mono coils work very well in hot ground on the Tdi machines. Much better than the duel field coils, this is obvious when it comes to ground balancing the machine and ground noise.  As  per earlier posts no surprise you are having difficulty with the larger 12 inch duel field coil. 

In my experience if you were to hard wird a coil on the Tdi Beachunter, my choice would be limited to mono coils. Second I would not go under eight inches or over ten. Thus my advice is limited to coils I have used on both the Tdi Pro and Tdi Sl.  First choice would be a Whites coil, the Super Pulse 220. It is 9.5 inches and a mono. Ground balances and performs well. Hard wired it would be a great do all coil. Much better on small targets than the larger 12 inch White's mono. Pity Whites didn't offer this size coil as an option, earlier White's beach PI machines had this size prior to the introduction of the 12 inch duel field coils. 

Second pick would be the Detech 8 inch mono, very sensitive, high performing and water proof. Solid construction and highly recommended. Suspect both coils would have 'flotation' issues etc. Both are my 'ideal' size and do the job as all rounders. I suspect the White's coil would be easy to obtain in the USA and the Detech simpler to find in Australia.

If it was me, I'd put the White's Super Pulse 220 on the Beachunter, hard wired it would be my ideal.  A White's coil on a White's machine. You could always swap it back if it didn't work out, so don't cut off too much cable etc whatever you do.. Should mention this coil works well on the beach and the goldfields. I've tested it in Victoria's goldfields, no issues with ground balance, quiet operation, smooth and stable performance. Much quieter and easier to use than any duel field or folded mono coil. 

All the best.

I use a Xtar  VC4 to charge 4 x 18650 at the same time. It has a usb connector so I can use it at home, in the car, or plug into my folding  solar panel when off grid. There are many quality chargers that will recharge aaa/aa/18650 etc the VC4 is only one of many.

It must be said, that big 12 inch duel field coil does suffer in hot ground. Parts of Western Australia are almost like being on an iron stone plate, that hot.  In some parts of the state the ground looks like something from Mars... 

For those using the Tdi Sl, in my experience the hotter the ground then the smaller the coil.  Large Duel Field coils suffer more so swap out for a smaller coil, quietest being a mono. Much easier to ground balance and it runs smoother and quieter. Part of the difficulty can be attributed to the single turn ground balance knob.. ten turn would be most welcome. The ability to switch into Low conductivity also makes for quieter operation, at a cost.

Whitbey in theory the Tdi Beach Hunter should to some extent operate like a Tdi Sl mounted with the 12 inch Duel Field coil with conductivity in ALL. Having said that, it means in theory it should work reasonably well on the goldfields. I have used the 12 inch Duel Field coil on the Victorian goldfields on a Tdi Sl, took a bit of time to get the ground balance 'just' right, there was a degree of 'ground noise' that had to be endured.  Due mainly to the size and character of the coil compared to a smaller mono for example. With my experience on the SL with this coil I conclude by stating it will be more work to ground balance and  operate but it is still fully functional despite being a bit noisy.  Since the coil wasn't hardwired I did swap out for  a smaller mono which was easier to ground balance, ran smoother and was more stable. As Tony state the machine may well be pushing its limits if the ground becomes very hot and you would be better served by other machines. 

 Until you actually try it the question remains. You are not the only one asking this question, particularly in the USA were the soil conditions are perhaps less severe than those encountered by me in Victoria Australia or by Tony in Western Australia. The ability to take your beach machine into the goldfields is a bonus, perhaps into the rivers and steams in those areas.. certainly an area worthy of exploration.  All the best.

I remember this was part of the video on the DVD that came with the Tdi Pro here in Australia. Just noticed it today on the 'tube'., looks like Jimmy was doing OK back then as well. Hope he goes well past 100, swinging all the way. Poor Digger Bob sounded a bit ill near the end.... nasty cough..

Like the Jimmy chest mount for the control box, makes sense on the beach and hilly country. I'll have to try mine out now after watching this video. 

Spot on, the price is half what was charged locally in Australia  for the original packs that came with the machines..  So buy this pack  that is ready to go, or buy new cells and 'open up' the old packs and swap over for new higher capacity cells then re apply new heat shrink plastic etc.  The pack I'm looking to build has 5 in series for higher voltage but less run time. Lot of Tdi Pro users in Australia would be well served by this battery Tony, well spotted.

Tony the Tdi Sl uses the same battery pack as the Xl Pro, Mxt etc.. The Tdi Pro uses a 8 x 18650 battery pack, 14.8 volts. It is actually roughly 16.8 volts fresh off the charger. The Reidman 5 cell pack comes in at 21 volts fresh off the charger and runs at 18 + most of the time.

Anyone with experience with the Reidman  battery for the Pro, please let us know what to expect.. no smoke coming out of the machine?  Some of us are looking to update or refurbish our Pro battery packs. I'll probably replace the cells with newer higher capacity cells in my older Whites battery pack after this.  But I'll start with the 'Reidman Replica' and then see where I go from there.

Tony the images show how the battery connects with the Tdi Pro, nice and tight. Heat shrink battery wrap is the key here. You can see how it plugs in.. All the best.

Despite a valiant attempt with a Dremel tool, a five cell removable battery holder will not fit in the Tdi Pro. That few extra millimetres taken up by the battery holders betrays the concept, it is a dead duck folks. Four removable cells is easy, five has me defeated. The idea of leaving the battery door open and using an 'external' battery doesn't sit well with me. I like to do these things properly so I will invest a little bit of time and effort.

Gave it some consideration and decided to go the full 'Reidman' style battery pack instead. Heat shrink wrap, circuit, and dedicated charger. This means quality Panasonic cells combined with cheap Chinese sourced charger and circuit. Given the realities of the global health crisis, there will be some delays. I have not given up, just upgraded from a quick and simple test to a full battery build project. An electronics technician and family member tells me it's all too easy, hope so. Including all five Panasonic cells, circuit and charger it should come in at $100 Australian Dollars or $70 US. All the best.

Jim in Idaho, I am sure 'Reidman' did a five cell battery pack for the Tdi Pro going back a few years now. I'll just do the simple version with a five cell holder, nothing fancy. Works well for me to be able to remove the batteries and swap out in the field and better for the cells since I use a quality smart charger. I can used protected 18650 cells, don't have to worry about over charge or discharge..

Yes I will have to do another comparison test, the extra voltage demands it.  

Again I think the combination of a modified machine with the higher voltage battery pack is about all I can think of when it comes to maximise depth potential. 

I'll complete 'playing' with the Tdi Pro modified unit by making a five cell battery holder. I've used the standard 8 cell White's battery and I have made a 'emergency' four cell battery holder. I will expand to the five cell holder and give it a go. Not the first to do this so I'm not too worried about damaging the machine. Should be around 21v hot off the charger and give an honest 18 plus volts most of the time.

Just plan to combine a two cell and three cell holder into a single five cell unit, pretty simple. Just an expansion of the earlier 4 cell holder. The Tdi Sl likes a little extra voltage so I'm keen to see how the Pro works with a bit extra..  A modified Pro with upgraded battery voltage, about as far as I can go with this machine I think..

The standard Pro machine with the Sadie coil with quick ground balance on video, then switch to Low and finally the Digger 14 x 8 in All and Low. Just shows that sometimes ground noises cannot be eliminated, just managed... All the best.

The location used for this comparison between the two Pro's is German Gully near Fryerstown in Victoria. The ground is very hot, has been worked and surfaced in areas. Produced nuggets, iron stone and hot rocks in quantity. Ground moisture is very low, very very dry.

Test results were only done with the Sadie coil, I have included old results done  years ago at a different location with the standard Pro. 

Soil moisture during the 'old test' were much higher, I am thinking that and the different locations explain the different results.

Old test,                         1 grain gold ingot 6cm, half gram gold coin 21cm, gold half sovereign 27cm.

Standard                       1 grain gold ingot 9cm, half gram gold coin 16cm, gold half sovereign 21cm.

Modified                       1 grain gold ingot 11cm, half gram gold coin 17cm, gold half sovereign 21cm.

So the modified unit has a small gold advantage, smoother threshold , all else being equal..

Video to follow shortly.

Due to time restraints and excellent prospecting weather, I only compared the two pro's with the Sadie coil mounted. I did use both with the Digger 14 x 8 and the Nuggeteer 18 x 6 also, but not for testing, just looking for gold..  The location of the tests is shallow ground heavy in ironstone and hotrocks. Beautiful colour quartz and lots of red earth.. Both machines were stable, ground balanced well and suffered equally. The Sadie coil was stable but transmitted a bit of ground noise on both machines, both were good in ALL conductivity but excellent in LOW. No differences here. The big Digger coil was very good in All conductivity and superb in Low, much quieter than the Sadie coil on this location. The previous gain advantage the modified machine enjoyed on the beach and in air tests,  did not show up in ground tests. Both machines managed gain around five or six, no clear differences here.. Again threshold was smoother on the modified machine, apart from this they operated in the same fashion and behaved the same out in the field. More information and videos to follow shortly..

It must be said that you can run the Tdi Sl with ground balance 'OFF' when using the small Tdi 6x4 coil. I tried it in a very quartz infused open cut, worked very well. Tried again in an area with iron stone and hot rocks, no joy since it is very noisy and picks up all the hot rocks etc but ground balance was easy and once set up she ran very quiet and smooth in this location.  I will upload a link later since I did shoot a bit of video with the SL without ground balance, then  with ground balance etc. One location pictured shows the Sl on a log  in an area cleared by fire.. 

On the road...

Dug the coil out of storage, mounted it on the Tdi Sl and all is good to go. Just feels weightless mounted on the Tdi Sl, this rig is super light and well balanced. The lighter battery pack helps also. I could swing this thing all day. Also looking forward to heading out into the goldfields, all has been organised for early in the new week.  All the best.

On 12/9/2016 at 1:29 PM, Hard Prospector said:

For the small shallow nuggets in nasty mineralized ground, learned a long time ago not to use any coil on the SL larger than 10" (actually, the smaller the better). Hence, at the 8usec and smaller TDI coils a perfect match. Dan Geyer for a brief time made a TDI 4x6 Mono "Shooter" coil that runs so well on the machine that I can run the gain/sensitivity maxed out and the ground balance turned off EVERY TIME I use it and thats no kidding. The Miner John 5x9 Folder Over, Jimmy Sierra 6x10 Duel Field, White's 7.5 DF and the White's 7.5 Mono Aussi have also been good nugget producers and pretty much in that order.

I am 100% convinced that making these easy mods. could really be a great thing for the SL as a nugget shooter and revenue producer for White's.

 

I knew I had read this somewhere, taken a few years to get around to doing this, looking forward to trying it out. I have used the small 6 x 4 Tdi coil but it never occurred to me to try it with the ground balance off.. 

Never managed to find a Razorback 'Piglet' locally, so jumped on the Whites made 6x4 Tdi coil. The Tdi coil uses the Whites 6x4 housing used on the 'Shooter' coils. Images tell the whole story. I'm hoping that the small footprint will have much less ground affect and allow me to avoid the ground balance. Worth a try..

Jim in Idaho, in the last threshold target response video  I had the Sadie on the SL, the standard pro had the 14 x 8 Digger and the modified unit had a Super Pulse 220. I'm taking the Sadie and Super Pulse 220 coils into the goldfields plus one larger coil, probably the 14 x 8 Digger. So we have one small, one medium and one large. Targets will be the one grain gold ingot, the half gram gold coin and the gold half sovereign. I will bury the targets and will choose the same location as previous tests. The ground effects will be significant and will tell the real story. I'll test using a pulse setting of ten, normal ground balance, then repeat tests in both Low and All conductivity.

On a side note, I'll take that small Jimmy Sierra 6 x 4 Tdi  coil out as well, just interested if it will allow me to run with ground balance OFF in hot to moderate ground, just curious..