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Well, thanks to forum member YubaJ I just ended up with a very slightly used White's Sierra Pulse Pro, or as it is more commonly referred to, the White's SPP. Bonus is it came with three coils, the standard 12" round mono, a 6" round mono that was part of an introductory special when they first came out, and a 5" x 9" Miner John folded mono coil. The Sierra Pulse Pro is nothing more than a White's TDI SL with the Conductivity switch and Pulse Delay knob both removed. The unit is locked into the hottest 10uS pulse delay. It is a limited availability machine only available from west coast dealers and in Australia. The whole story on how it came about is kind of interesting and detailed in my original thread on the machine from May 2014 at http://www.detectorprospector.com/forum/topic/213-whites-sierra-pulse-pro-whites-spp/ Now you may ask, why did I get this detector? There is a story there also. My first detector was a White's Coinmaster IV that I purchased in 1972. My first detector dealership was for White's in 1976, and I have had good success using many of their detectors. I currently have a White's V3i with Bigfoot coil that is my jewelry machine for large parks and sports fields. Bottom line is White's and I go way back. Whether I intend to use them myself or not I like spreading the word about on new models others might be interested in, so I perked up when the SPP was announced. I was more than anything just excited to see a ground balancing pulse induction machine introduced for under a grand, plus I always liked the ultra light weight of the previous TDI SL model. So I really was kind of pumped up to get one and posted on a few forums about it. Now, I used to hang out a lot on the White's Electronics forum at http://forums.whiteselectronics.com/ to just offer some free help and support as one of the only people there that seemed to know much about the White's GMT and TDI models. I made a post there identical to the one on this forum at the link above, and I get this message from the moderator: "Had to remove the Pic and "Sierra" name from the title of your post. The SPP is a Jimmy Sierra product, and as such isn't allowed to be "advertised" or "plugged" on the open forum." I posted again, something along the lines of "WTF it is made by White's and is sold by White's dealers but because it says "Sierra" in the actual name of the product I am being censored?". I got another message saying my "rant" had been deleted and the issue forwarded to the admin. That was it for me - I banned myself and have not participated there since. Jimmy Sierra later contacted me to apologize and he did set things straight with the people at the forum but water under the bridge by then. Just another example of the strange and convoluted politics at White's Electronics. I had been all fired up to get the SPP but just put the whole idea aside at that point. Yet down inside I still wanted one. So when by pure chance I saw this SPP for sale at a good price I pounced, purely as an impulse buy. I have no real use for the machine and will probably sell it but I want to play around with it a bit. The main thing about the White's TDI SL and the SPP is they are crazy light weight. The machine weighs about 3.5 lbs with the 12" coil and right at a perfectly balanced 3 lbs with the smaller coils. This is what the Garrett ATX or Minelab SDC 2300 could have been and should be packaged like. After swinging a GPZ 7000 all summer the SPP feels like a feather! Now, the TDI SL and SPP models are not high power pulse units and like the Garrett Infinium they really do not do any better in low mineral ground than a good VLF detector. However, as ground mineralization and hot rocks get worse there is a crossover point where the problems these conditions cause on a VLF (loss of depth, false signals) can be overcome by using a ground balancing pulse induction (GBPI) detector. Something many people do not understand is that by adding a ground balancing circuit to a PI some depth is lost in an absolute sense, and this is very easily illustrated with the TDI/SPP models in air tests by just turning the ground balance off. The machine gains quite a bit of extra punch, and a nice thing about the White's GBPI models is they have this ability to be run in pure PI mode in low mineral ground. In particular this makes the original TDI and TDI Pro models some of the best beach PI detectors you can get your hands on. In the case of the TDI SL and SPP however running the machines with ground balance off is almost the same as running a good VLF in all metal mode. The only difference is you do get the ability inherent in all PI detectors to ignore some ground conditions due to the pulse delay and how it works. See Understanding the PI Metal Detector by Reg Sniff for details. More about the SPP versus the TDI SL. The SL comes with what White's calls a Dual Field coil, which is basically a small mono running inside a large mono. The coils look like doughnuts, the outer rim being the large coil, and the inner circle being a smaller mono coil, both running at the same time. The theory is the depth of a large coil with the small gold sensitivity of a small coil, all at the same time. The problem was these coils were a bit too hot for Australia, and so the SPP coils are just regular mono coils. Easy to confuse also because a 12" Dual Field looks identical to the regular 12" mono. My unit has both the 12" mono and a 6" round mono that was part of an introductory special (now over). The SPP was a killer deal at introduction with two coils for $999.95. It is now being advertised new with a single 12" coil for $999.95 but is being offered by at least one dealer for $899.95 with the single coil. I really like the little 5" x 9" folded mono coil and scuff cover that came with my unit. What is a folded mono you ask? Something Reg Sniff came up with, details at Link deleted since Findmall Forum update broke all old links Basically his answer to the White's Dual Field, which was patented. Miner John sells these for $199 at http://razorbackcoils.webs.com/apps/webstore/products/show/6277891 and it is probably one of the best coils you can get for a TDI to hunt gold. Finally, the SPP is interesting because it really is a TDI SL under the hood. The plug in connections for the Conductivity switch and Pulse Delay control knob are still on the circuit board, and the SPP can be upgraded back into a TDI SL for just a few dollars in parts. Here is a thread on adding the Conductivity switch back in at https://www.prospectingaustralia.com.au/forum/viewtopic.php?id=13934 You can see the little white plastic sockets on the control board picture below marked conductivity and pulse delay. Anyway, just got this and no time yet to do more than take pictures and post but when I get time more will be forthcoming.

Just thought I'd share the settings I use when I'm out hunting for gold in Australia. First setting: General gold detecting Set pulse delay to 10' Ground balance in ALL as best as you can' between the high and low tone. Flick into LOW and sweep the coil if your getting ground noises which I generally do just turn the GB up half a notch' so from 9 go to 9.5, if need be you can go a full notch without any huge loss on depth or sensitivity' this should now allow you to use full gain. Dig all high tone responces and listen carefully. Just note that running Low you will only find gold up to about 7-10grams If you still continue to get strange sounds that you can't ignore by advancing the GB setting, try the the GB process all over again but at 12 pulse delay. Second setting: large deep items When Using HIGH set pulse delay at 15-20' ground balance in ALL as best as possible' it will actually be a lot smoother because of the pulse delay setting' flick into HIGH, to remove any ground noise you now "reduce" the GB setting a little say from 6 go to 5. In High you will only detect targets the machine thinks are high conductive and any gold over about 7 grams, don't be concerned about loosing small gold you won't detect it anyway so in this setting run big coils and Use full Gain if possible. Dig all repeatable low tone responces if it turns out to be ground noise reduce the GB setting more up to about 2 notches from the original GB setting or do the GB process again but at a higher pulse delay. This setting will go deep expect big holes. Set the frequency correctly if you can't, use the machine away from EMI but generally the TDI doesn't suffer that bad. Iv found heaps of gold with the first setting so it does work well' but I'm yet to find a massive nugget with the second setting but the deep items I'm digging up shows one will be gold hopefully soon. Hope it helps.

The wait is over my new TDI pro has arrived and I am impressed, The Build quality is about the best I have ever seen on any Detector, I knew it would be good but I did not expect This and the attention to detail is incredible, All of the Controls are firm yet smooth, it is about as perfect as anything could be, I cant wait to get out there and get in to it, John

Hi everyone I am stuck with a choice to make, The problem is I have a TDI SL and I been wanting the TDI Pro for about 5 years but they do not import it over here but now Whites have agreed that I can have one due to some leeway in transporting the batteries, I have always wanted the pro and in the end I bought the SL Only because they did not import the Pro and now I can have one Is it worth my while to buy it, Being so close to getting it is now having a knock on effect of am I doing the right thing, There is less than an Inch when it comes to depth between the 2 machines, But the real Bug Bare for me is am I ever going to be able to turn the gain above 5 or 6,, I have seen a guy doing those tests comparing all the PI's and he has the Gain running flat out, and it seems to be running very well, I would go as far to say Smoother than my GP 3500 use to run, If anyone has any info of factual use that would be great to here your views, along with how high you can run them etc because if it cant go above 5 or 6 then my SL is going to be deeper maxing out at 10, There seems to be many folks talking about how the Pro warbles is it really that bad, baring in mind I run my MXT and the GMT just where it starts to warble depending on my mood and patients, I am not bothered about chest mounting the machine because I like to get away from the machine when I am digging So am I making the right choice, ?? Note I was going to buy one of the 4500s but because of the junk over here it is impossible to work a PI without some form of Disc system, Yes I do want the Pro,, Is it a wise choice ?? Is it any better ? can I run it up around the 8+ mark without losing targets due to the warble?. the SL is a great machine and I have some new battery tests coming up which I will add to the Battery Thread, Thanks Guys,,, john

Steve has this article been removed because I have tried to read it a few times and I keep getting the Error 404 page?? Thanks, john

Steve, I just read your TDI Moore Creek Review and In it you said the you managed to run the TDI At Full Gain, Yet I have heard tales stating that the TDI is Noisy, So what I am asking is it the Location that made the TDI Quiet so you could run it that Hi or Is The TDI pro more Noisy than the TDI you Have/Had, Because I have read many times that most people can not run them about 6 on the Gain,?? Thanks Steve. John

Posted the following on a particular site and almost immediately picked up ridicule for adjusting the TDI in the manner stated. I'm a very open person and can take constructive criticism if need be. After several hours hunting with the TDI SL I finally found the perfect settings for this particular site. This place is littered with the waste bi-product of burnt coal over many years. Much of the waste is small in size, ranging from BB to marble size and the smaller pieces easily attract to a magnet. In addition to that, the area is littered with nails ranging from 1 to 4" in length and some up to 4" deep. These nails, especially the larger ones give a good audio, especially with a ground balance of 8-9. After a suggestion from Reg, I began adjusting the GB to 4-5 and if the signal became inconsistent then the target was most like a nail. After a lengthy amount of hunting I decided to run the machine at gain max, pulse 10 and GB of exactly 5. Surprisingly the false signals all but stopped and I started finding old copper pennies some being wheat pennies in an area where I had gridded off and cleaned out of all good targets. Amazingly, I still can't believe I had missed that many targets with my other machines. Now my next plan is to locate, what I believe to be good non-ferrous targets with the SL and mark each location. Then use my regular VLF machine and see if I can detect each target and note the audio responses given. Many things to consider in this journey, very excited to say the least. Well it seems some people on other sites think it is a sin to adjust the TDI the way I did in the following statement. I want to add one thing; the ground I hunt is very unique. All I'm stating below is what I observed and found to be true at this site on this day. I'm very well aware the best settings would be GB 8 and pulse 10, but the ground does not allow the best settings to be used to produce what I'm looking for. Coins mixed in with heavy coal waste made of iron, BB size to marble size to be exact. Well, went back to the same site where I posted, "perfect settings for this site" and hunted a small area not more that 60' from the prior hunt. Used the same settings "GB 5, pulse 10 and gain max" and off I went. After a short while I noticed a lot of clipped or inconsistent audio reports. Decided at that point to reduce gain to 7 and continued. Hunted a few more feet, still clipped audio, strange, so I stopped to analyze the area a little more closely, sweep in one direction and get a some what good audio, but the return sweep was either silent or chatter. Suspecting something was the cause I stopped and increased the pulse delay up a tad, nothing changed. Continued to increase the pulse until I reached 17 and suddenly the audio came through as a loud, almost overload low tone. Thinking it might be a nail; I dug and out came a copper penny at less than 4" deep. Now to say the least, I was excited and puzzled. Decided to start over where I started hunting and experiment using a pulse rate of 17. A few moments later came the same type of loud low tone. Thinking there is no way I missed that one my first pass I changed the pulse to 10 and the signal all but disappeared. Increased the pulse to 20 this time and spent over 5 minutes rotating around this target checking from every possible angle to see what might be causing the anomaly, switched the conductivity switch to all and still a consistent low tone with nothing else mixed in. Now one must keep in mind I'm using the stock 12" and at times it is very difficult to exactly pinpoint where the target actually is. Changed the pulse to 10 and the low tone practically disappeared. Now I was wishing I had brought my Deus to recheck some of these inconsistent signals, maybe next time. Well anyway I dug a nice plug and out came a wheat penny at less than 5" deep. I was very excited to recover something from an area that quit producing years ago. Continued hunting with settings of pulse 20, GB 5 and gain at 7, and found many more coins dated in the early 60's all within a 3' path some 60' long. Already planning what I'll do my next hunt. What I learned from this hunt: Regardless of what some may say, don't assume you have the best settings for any site especially the sites where coal waste has been discarded for many years. I'm suspecting the partial or complete cause of the anomalies is the small BB size waste particles from the coal fired furnaces that will easily attract to a magnet. In fact dropping a strong magnet into the same hole where a coin was revealed exactly that. I'm relativity sure I need a mono coil, but undecided as to what I'll get. More reports to come.

Whites TDI SL Went to an old school where the coal cinder waste has been dumped for years and hunted for 1 ½ hours. This area has been grid hunted for years and I was sure there were no goodies left to be found. Well wrong again. GB to a little over 8, pulse 10, gain 10 and off I went; very first signal was a wheat penny at 4-5 inches and perfectly vertical. You can see the scratch I made with my shovel. Wow, was I off on my pin pointing skills. Couldn’t believe how I could have missed that one because it gave a very good, consistent audio response from every direction. One thing I noticed, it didn’t give a double beep like a VLF machine would on a vertical coin. Thought I had the sound nailed down, but was I wrong. Started digging nails, three to be exact, all sounded fairly good but I could tell there was something wrong, but I’m learning, so I dug anything that sounded remotely good. A few minutes later, not more than 10’ from the penny, another signal that sounded different, not sure what sounded different, still learning. Wow, a silver dime and not quite 5” deep. Now I am wondering how I could have missed that one, not a clue yet. Well anyway, the next two targets were nails, then another perfectly vertical copper penny. Had a very good hunt, for an area that basically dried up over a year ago. Wonder what I'll find once I have a little time on this machine?

Well a good while back I finally decided and purchased a Whites TDI SL. As always, each new machine has to pass through my test garden. Did some detailed work in my test garden yesterday using the TDI Sl. First results are very promising. Settings were, pulse delay 10, ground balance 7 ½, gain max threshold just audible. I have a copper rivet buried at 7” about the size of the end of a pencil eraser a 6 ½” quarter, dime, nickel and penny along with each at 4 ½” deep in a different part of the test bed. In addition to these I purposely left nails where they were when I planted the garden over 7 years ago. Please keep in mind these were the depths when I put them in the ground, so the exact depth is not known after 7 years. Starting off in high conductor mode each (except the nickels) gave a very good, smooth audio in every direction except the nails which gave a completely different sound, very much different. Keep in mind I’m still in a steep learning curve, by no means close to experienced but having a fantastic time on my journey. After listening to the differences between the coins and nails I reduced the gain to about half and listen to each target again. I continued reducing the gain little by little until the deep coins and rivet ceased giving a audio response and that was about gain 3 ½. Raising the gain back to 4 and the coins gave a very faint, low volume tone. Wanting to play a little I raised the pulse rate, re-ground balanced and checked each target with a gain setting of 6. The biggest difference came when the pulse rate was set above 20. The coins still gave a good audio, but the rivet, which is very small compared to the coins, became difficult to hear, very statically, extremely low in volume. All in all I had a very enjoyable evening, very educational. Mark Gillespie

Just with the Minelab PI coils being used on the TDI's. I've heard that once you get over about 14" with some coils the TDI's struggle to run them regardless of pulse delay settings etc? Was wondering if anyone has had any success with a larger coil on a TDI? Most, in Australia at least, seem to have success with smaller coils on the TDI series like NF Sadie & 12" x 7", 14" x 7/9" etc. Only ever heard of one being used with a 16" Coiltek but never seen or heard back any results with it, although I see one bloke said he tried one & then sold it going back to a Coiltek Blitz 14" x 9" which runs fine at 10uS. They seem to do well on small gold with the smaller coils here @ 10uS.Was wondering if this is why Miner John/Razorback are making coils specific to the TDI & Minelabs I.e. they have a 14" round for the TDI but it's not compatible with the Minelab PI's. They do however have other coils specifically for the Minelabs.

A couple of recent posts referred to the whites TDI – so I thought I'd pass along the following. Last week I purchased a secondhand TDI from a guy who had sent it in to have Reg Sniff's noise reduction mod done - along with replacement of the op-amp. I had a TDI previously and the difference between that one and this one is like night and day. My old one had a warbly threshold that drove me nuts and made it very difficult to use the sensitivity higher than about 2/3 of full. My house is EMI hell, the neighborhood has underground utility service and the transformers sit on the ground. Even mildmannered VLF's like Whites Classics go nuts here at full sensitivity. This TDI has a silky smooth threshold with just an occasional blip at full sensitivity (12). It also air tests 17" on a nickle with the standard 12" DP coil! That's 4" more than I ever got with my old TDI here at the house with the same coil. I have been playing with the silver coin hunter trick with the high conductor mode selected and the GB offset to kill all ferrous. It really works - with the GB on 4, I hear no iron - and a quarter that I buried down 8" about 5 years ago gets a good signal with 2-3" air gap even using a 10" elliptical Coiltec mono. Now I need to find a dead Bigfoot coil and build a mono PI "Bigfoot". The mods were $125. Reg could probably furnish current details.

Comparing the TDI SL and The MXT Pro (12") I was wondering if anyone as Compared these Two Machines, Because the SL is an in between machine, Between it and the ML 5K, I have been wondering about these two machine Because I have Read Stories about people Pulling One Ounce Nuggets at 18" At Gains Creek with the MXT fitted with the 12 inch Coil, And I have seen Coins come up at over 13" with the same setup with the Gain set between 6.5 to 7, Yet I have never heard about Deep Nuggets found with the TDI SL, and I have heard about people digging Bobby Pins on the beach with the TDI's at 16" to 18", In Air Tests My GMT with the standard 5X9 coil versus the TDI SL, On a Round Flat 1 1/4ozt Lead Nugget TDI SL = 18" and the GMT = 21" set at 7'5 (pre set mark) So I could do up to 10 if conditions Allow, But considering the SL has a 12 DF mono I would never of expected that to happen, Like The MXT when you Turn The GMT up you Can hear it Changing Gears so to Speak as it Multiplies the Gain, Has anyone here found any Deep Nuggets with the SL, I know that someone in OZ found a 5.6ozt nugget AT 32" using a 20 NF Coil, I have picked up Large Iron at have 4 foot deep and the subway Tunnel at over 6 feet deep, But as winter is all but over I am hoping to get out and do some testing ect, Thanks Guys,, John

Great updated thread with photos by Jim Hemmingway at http://www.treasurenet.com/forums/metal-detecting-gold/461891-white-s-tdi-pro-northeastern-ontario-silver-country-revised-edition.html

I was curious just how a dual D coil would work on a TDI and this is what I found but first, I need to say my Dual D differs a little from ML's or Minelab's design a little. The reason is simple, I wanted to use what I already had made and just modify the mounting. My main TX coil looks basically the same is those in the posts of the dual D coil, but my RX coil is a little different. Instead, my two D coils are part of one large winding shaped into two D's, with a half twist in the leads passing through the center of the TX winding A simple half twist puts one winding out of phase with the other RX winding, so cancellation is the same. Ok, here are the results. First, the coil is quite sensitive, very quiet, and requires no ground balance signal at all. At least, it doesn't at my house. The detector is so quiet with or without the GB on, it is clear that I could increase the gain and, thus, the depth when using this coil. The coil housing I used is a 12" by 9" so it is smaller than the factory 12". However, the sensitivity is close to the same I am also betting I can increase the windings in the receive with little to no major noise effect,and possibly a little gain. I also have an idea to increase the gain another way. Right now, I see a depth increase on the TDI since I can run with the GB off just fine even over really bad ground, but I feel I can do much better with a few other tricks. So, it is possible even the old detectors have life left. Reg

I am in the market for a pi detector for beach hunting. I cant afford new so used will have to do me. The TDI Pro is at the top of my list but I do have a chance of picking up a good GP3000 with DD coil at the right price. I know that the Minelabs are not to fond of salts so I am wondering would the GP compare in performance, depth wise to a TDI?

After Reading many post about the TDI SL The Topics always Returned to the Issue about Batteries so I thought I would Buy A Few Dozen Batteries and put it to the Tests Because I think that most people are Holding Back or putting off buying a really Good Machine based on the Issue of the Batteries, So I am posting this in order to let people see that The problem is easily solved and is A lot Cheaper than you might think, HH I have done Tests with Batteries here's what I Got, 1) The Standard HD 2200mah NiMh Pack 4 hours 20 minutes 2) The Dry Cell Pack Fitted with 8 X 2650 mah NiMh AAs =(11.63 volts) 6 hours 37 minutes 3) Modified Dry Cell Pack to Fit 9 x 2700 mah NiMh AAs =(13.009 volts) 6 hours 38 minutes NOW IF YOU USE:- Righto If you use 2900 mah NiMh Batteries you should get Around 7 and A half to 8 Hours Run time, which is more than enough with out Taking A Break, So My Advise to All You Fellow TDI SL Brothers and Sisters, Is To Use the Dry Cell Pack with either 2650s, 2700s or 2900s As Your Main Pack and use your Standard HD 2200 Factory Pack As Your Backup, Using the 2650s and the 2700s works out 4 X Cheaper than Buying the RNB Pack. NOW YOU:- Now You might of noticed that I Modified the Dry Cell Pack To Except 9 X AA's, Why you might Ask??, Well many People have Claimed that By Increasing the Input Voltage That you would Get More Depth?? Well It Did To A Degree But it helps the Sensitivity more than depth because it is running at A Peak Voltage, Is it worth the $10.00s to buy an extra Battery and the Single Battery Holder, Maybe?? But for ease of Use I am Going back to using 8 X 2700+ Batteries, Although I was Running A Higher Voltage It did Not Give me more Run Time as I expected, Because when you increase the Input Voltage that has A Down Side, Because The TDIs will Consume more Amperage as with all things Do although that 13.00 volts does give you a Happy feeling Inside, If you are going to Carry Disposable Batteries then Only Use Energizer Lithium's as they have A Much higher Voltage than Duracell's and Normal Energizers at 1.61 Volts, Where AS The Energizer Lithium's Have 1.83 volts which @ 8 X 1.83 = 14.64 Volts, DON'T PANIC Because the TDI SL Can Run 16.00 Volts Safely, OK, NOW These Energizer Lithium's Have A 10 Year Shelf Life, and have Working Temperature of -40*c to + 40*c++, and they are the only Battery that Is Guaranteed Not To Leak, So If you Own ANYTHING of Value to YOU Only Use these Batteries In It and Even more So with your Detectors because The High Voltage Makes the Machine A Bit Deeper and A Little More Sensitive and A Longer Run Time than Normal Energizers or Duracell, Please Note That Duracell's work Better than the Normal Energizers because Duracell's power slowly goes down, Where as Normal Energizers stay Bright and then the Voltage suddenly drops Fast and if you are using them in a flash light/Torch Then Don't Be Surprized if you find your self in the Dark, Anyways I hope this Helps, John,

Hello Steve, I was going to wait until March 1 to see if Whites was going to come out with a water proof TDI or TDI SL. Not Going to Happen !!!! So....I purchased a new TDI SL and made a few modifications to make it at least "splash proof". Is it water proof....no. Will it protect against an errant sand grain or two, sea spray and an occasional splash....I hope so. I know it is not pretty, but you do what you need to do. Take Care....Jeff

I recently acquired a through hole version of the TDI with the sole intent of modifying it to run the 8 uS pulse delay. Does anybody know the procedure for this? I will also need help in getting a coil to run properly with it as well. Any assistance would be greatly appreciated. Thank you.

I have been expecting this one and oddly enough I am pretty excited about it. "Why oddly" you ask? Normally I tend to go for pure horsepower. Instead in the new White's Sierra Pulse Pro what we have is simplicity and killer bang for the buck, in a lightweight, well balanced detector. In a nutshell the Whites SPP is a TDI SL ground balancing pulse induction metal detector with the control set focused down to exactly what you need to hunt gold nuggets. And best of all White's broke through the $1000 price barrier offering the first ground balancing pulse induction (GBPI) metal detector for a manufacturer suggested list price of only $995!! And that, my friends, is something to be excited about! The only caveat is the name. Pulse Pro implies this is some kind of super powerful professional PI. Don't let that mess with you and lead you to believe the SPP is something it is not. There is nothing new here per se. But again I am excited by this detector because I am a bit tired of heavy overly complicated expensive GBPI detectors. In my opinion this is just what the market needs. A White's customer can walk out the door after cutting a deal on a GMT and SPP together and have on heck of a fantastic combo gold getting setup that will get most gold under a wide range of conditions for way less money than most single GBPI detectors currently on the market. The SPP is locked into the hot 10uS pulse delay mode for best gold sensitivity. The conductivity switch is eliminated to insure you hear all targets, but you still get the tone responses that help identify many ferrous items. Intriguing to me is that the model comes stock with a normal 12" mono coil instead of the 12" dual field. This gives up a tad on tiny gold but offers smoother performance in bad ground and hot rocks. Anyway, kudos to Whites. I gotta have one of these for rough and tumble detecting in extreme terrain. Only three pounds, battery and speaker included. But I will need a smaller coil for most of what I do. I wonder if White's can be talked into selling it stock with a smaller coil?

Hi steve, just thought I would drop a line on testing tdi at winnemucca 3 days. Ended up pretty good. walked a lot of the desert, found a lot of lead. Then I found a nice little area that has been over by numerous detectors before. The ground was to hot down there to run with geb off, so ran with it on Gain around 9 ground balance 9 to9.5 pulse 10 most of the time, low conductivity a little noisy but I could work with it fine.i havent weighed any thing yet nice heavy pieces though. Area I found I would test tdi against gb and there was two pieces tdi could not see at all. These were all flat pieces of vein very thin. Anyway was great weather after snow first morning, overall pretty pleased with first pi machine, especially knowing mineabs and everything else has electrified the ground here before me.

Recently got this tdi, have studied over and over everything I could get my hands on to gain a little knowlege of this PI. I have only hunted 3 times so far(6hrs.maybe) what a cool, machine never been around them but wanted to try one. First time out was overwelming, almost, wrote everythig down I did. 2nd. Time out was getting to understand it now, alot of experimenting found 8 coins and a lot of you name it.running in all full gain pulse 10 in this ground gb about 8. Wasnt sure if I had brought a long enough shovel for it's capability, wished I had a tape I dug 2 beer cans burried easily24 inches first 6 or 8 inches was dirt and rock then pure wet sand.It would have hit these even deeper, you guys that run these already now that. Trying to teach myself the different variations of targets, gonna take time for sure. Have a few questions I hope to get some answers to. By the way I ran 2 coils experimenting.(7.5-12") I did some air tests with some nuggets I have found with gb2, apparently the current doesnt hold well on porres nuggets under 6 grams, maybe my settings, but I tried with it set full power and didnt get much response on the porres, I think I read it cant hold current very well on targets like these, is that true and to what extent? Havent got to do any under ground testing yet ground still muddy and frozen. Thanks for any input here rick I want to take this to the desert shortly, now wondering if it will still go very deep on these big nuggets that could be over half ounce we now there are more here, just want some input on this dellima. just hoped it would go deeper than gb2 that have found several BIGnuggets here.

Last Saturday I decided to get out and enjoy the unusual, for January, weather here in N. Calif. I met my partner Reno Jim and headed for a spot we've hunted for years. We didn't expect to find anything, maybe a crumb that had been overlooked in all the trash. It was just a good day to get some exersize after the holidays. While Jim worked the banks digging trash, I started up a dry creek bed rechecking exposed bedrock I'd already hunted before. I came to a spot where a 10 ft section of new bedrock has been exposed. It looked like a gully washer had come through and blown off the overburden. It was just above a spot I had done well at in years past. I wasn't expecting anything as I had seen fresh dig holes further down stream. Within a foot of hitting the new bedrock I got a good signal which I knew for sure was a bullet. I scraped a bit of dirt off and the signal was gone. Checking the dirt, there it was, right on top, a nice little 1.5 dwter. Wow, that was easy. I wonder how that got missed. I moved another foot up stream, and bang, another signal. Again, I was sure it was trash, it was so big and loud. This one I checked with the pulse delay to see if it went away like a nail, but it was still there, so again, thinking it's a bullet, I scraped off the dirt and got the signal in the cup. It couldn't be a nugget, that first one was a fluke, the only one in all that bedrock. But, sure enough, out rolled an ugly 3 dwter encased in red quartz! At this point I thought I'd better call Jim over to hunt the rest of the spot. He'd been on a long dry spell. He hunted that spot the rest of the day but could only come up with one tiny little .1 dwt grain. I left him to clean it out and moved further upstream. Around the corner was more bedrock that I had hunted at least a dozen times over the years. A couple of nails later came a loud booming nail signal right in a little pocket of rock. And again, scraping the dirt out with the pick, again, I look down and see a huge flat nugget just laying there. I couldn't believe it! How could I have missed it before? Because it was SO big and loud, I just passed it up KNOWING it was trash. Geezz, you think I would know better by now. Glad I wasn't hearing nearly the iron trash of years past because I was using my TDI in low conductivity which knocks out the larger iron. We were both using the TDI SL with the 9x5 Jimmy loop. So, by the end of the day, we each had found one more small piece for a total of just over 1/2 oz. The big ugly slug weighs 5.7 dwt. Good start to the new year! Digger Bob

Back around 2008 I was involved with the use of the White's TDI in a very big way at my mine at Moore Creek, Alaska. I made various posts at locations around the internet on our success with the TDI but never did get around to collecting it all together in one place. Until now. I just made a belated entry on Steve Mining Journal titled White's TDI at Moore Creek, Alaska - Summer 2008. Lots of gold nugget stories and photos there - check it out. Also added a page about the TDI itself I am still working on but a ton of information there at White's PulseScan TDI Metal Detector already so went ahead and posted it. 0.31 ounce Gold Specimen found with White's TDI

Editors note: Mark contacted me regarding the use of a PI, specifically the White's TDI, to try and get better performance on coins at a difficult location. I asked him to post here to get the ball rolling on the subject - Steve H The reason I'm asking these questions is because where I live all the old schools used coal for their heat source. After burning the coal the waste was spread out over acres of land to get rid of it. Most is the size of a bb up to maybe a small marble. It is some sort of iron makeup because it attracts to a magnet fairly easily. And as you well know a regular VLF machine is rendered about useless with the exception of very shallow targets. Over the past 7 years I have owned or borrowed each of the following machines and none can get any depth over 4" in these areas. The following is a list of the machines. Tesoro Vaquero, Tejon, Lobo Supertrac, Garrett A250, Teknetics Eurotek Pro, Fisher Gold Bug Pro, F75 and the LTD version, Whites XLT, DFX, V3i, Minelab Explorer SE, Etrac and CTX 3030. Please keep in mind, not all the machines were mine. Some were loaned to me just to try in this bad coal cinder ground. One interesting note about the Minelabs, when auto sensitivity is used the machine will throttle down to 8 or lower in these areas. Now you might be wondering why I'm so interested in this one particular area well it is because it was one a huge group of ball fields used back in the 40's right on up to the 70's. I have pictures of actual ball players and at times there were hundreds of people watching games. Now that said, there should be many silver coins at this location, but none have been found and I can only guess it is the ground. Because over the years we have buried coins at 4" deep that none of the machines mentioned earlier can detect and 4" is not deep for any of these machine. So my assumption is that the material robs the transmit signals from the machines to the point depth can not be achieved. I have talked to Carl at Whites and Dave at 1st Texas about these extreme harsh locations and actually sent them each a 4 pound box of this material to test. Dave suggested ground balancing to the material and using the motion all metal mode to hunt. This provided some positive results, but only to about 5" in depth. On the other hand Carl was working on a PI prototype at the time and could only provide his comment, which was, no VLF would be able to perform at these locations. After reading many of your post and watching your videos I decided to contact you for additional information. I sent Carl another message after reading about your postings on the Whites TDI and here is his reply. Re: dirt Quote Originally Posted by markg Carl, a guy that hunted the digging in Virginia swears that the Whites TDI will punch through this kind of dirt. I know you can agree or not on this subject. But the cost of buying one to try would be a gamble. What do you think? Quote Originally Posted by Carl-NC just tested your cinder soil with a TDI... it's actually pretty mild compared to my Australian soil. The Oz soil is strong and has a very tight ground balance setting, whereas the cinder soil is weaker and has a broader GB range. So I think the TDI would handle this stuff easily. Regards, Carl I guess I really would like someone close to where I live visit and try a pulse machine. That way I would know. I can provide an open invitation to hunt about any evening.

ATX, TDI, GPX. What is it with detector companies and three letter acronyms? I liked it more when they were called Coinmaster or Goldmaster. At least that gave you a clue about what the detector was supposed to do. The three detectors representing the state of the art in ground balancing pulse induction (GBPI) metal detectors. The Garrett ATX, White's TDI, and Minelab GPX 5000. You rarely see them all pictured together so I thought I would post one. Garrett ATX, White's TDI, Minelab GPX 5000 These three detectors are all very good at what they are basically made for, which is dealing with ground mineralization and hot rocks that make using VLF detectors very difficult. In particular VLF performance is severely impeded in extremely mineralized ground. In low mineral ground a good VLF prospecting detector running in all metal mode can deliver results rivaling PI detectors with the added benefit of having good discrimination options. Anybody doing much prospecting, however, will eventually run into locations where ground mineralization and hot rocks makes using a VLF such a challenge that a good ground balancing pulse induction detector is the only real option. The GPX 5000 represents the current state of the art, and is the easy option if money is no object. It is well designed for long hours of prospecting, has an incredible variety of optional coils, and can handle most any ground conditions with many tuning options. The Garrett ATX provides performance that comes close to the GPX at a much lower price, with the added benefit of being waterproof to ten feet. Actually, this is only a benefit if you need it. Otherwise it makes the detector heavier than need be and limits the available coil options. Still, if the GPX is not an option the ATX would be my next choice in a new detector with a warranty. For those needed waterproof it is the only real option along with its predecessor, the Garrett Infinium. The White's TDI is an older design but still very capable. It costs less than the other two options, and unlike the Garrett it has light weight versions and models that can be hip or chest mounted. It is a good option to explore for those on a budget or needing the most ergonomic solution. The TDI is also a very respected beach detector, like the ATX above, but it has no waterproof option.