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I’ve recently had a few emails regarding my TDIBH so I thought I’d hammer out a response. I’m going to try and summarise with some dot points; I have close to 500 hours on this machine and run the 14.8v (nominal voltage) Lithium battery pack. Details in my earlier posts. The detector has found me quite a lot of big and deep gold. I don’t use it much in the water as conditions down here are generally quite rough. The 12” coil is physically too big in waves and white water. Also, digging 18” targets when you are being swept around by waves and swell is almost impossible even with 30 pounds of lead. The detector is now mainly used on the lower beach and low tide areas. I have had no issues running the 14.8v pack. I charge overnight and let the voltage settle down before using the next day as this avoids the off the charger voltage of 16.8v. My run time is about 6 hours before I swap out for a fresh pack. I have had no condensation issues within the detector. I do have a large silica gel pack in the battery compartment. The detector is quieter than other PI’s with the low delays when used in the shallow water and saturated hard pan. The SAT is very good in keeping things quiet even at low delay settings. Maybe it is the new Flux Capacitor that White’s now use 😉 I have several layers of yellow Plasti Dip on my coil to keep it well protected on the coarse shells and exposed reef areas. My ultimate power setting is minimum Delay and maximum Gain, threshold a fraction below audible with volume up high. Frequency is usually at the 12 o’clock position. I have only ever needed to change this once. My deepest ever finds have come from this machine. GB is always OFF unless I hit a rare patch of black sands. You need a BIG and STURDY scoop..............Tony

All-new patented 8"×12″ Dual Field coil for improved depth and sensitivity. Bonus 7.5″ Dual Field concentric coil for a limited time! To hunt all day, you need a lightweight detector that still provides high performance. The TDI SL Metal Detector has pulse induction power that provides unbeatable depth and sensitivity and is designed specifically for prospecting and identifying relics. Special prospecting features make life easier, such full-control ground balance that filters out the iron mineralization of hot rocks, black sand, and other tough grounds. This compact detector weighs only 3.5 pounds with its waterproof 7.5" x 12” High-Q Search Coil, which offers deep detection depth. Other accessory coils are also available. The rechargeable NIMH battery lasts up to 6 hours, and a backup AA battery back will power all-day exploration. Owner's Manual (for TDI SL series, none specific to High-Q) White's TDI SL High-Q Camo metal detector White's TDI SL High Q Technical Specifications* Internet Price TDI SL High Q $1099 (available in both tan or camo colors) Technology Ground Balancing Pulse Induction (GBPI) Frequency 3250 - 3370 Pulses Per Second Autotune Mode(s) Slow Motion Ground Rejection Manual, one turn control Soil Adjust Ground Balance On or Off (two position switch) Discrimination Conductivity switch*, 10 - 25 Pulse Delay Volume Control No Threshold Control One turn control Tone Adjust No Audio Boost No Frequency Offset One turn control Pinpoint Mode No Audio Output Speaker, 1/4" headphone socket Hip Mount No Standard Coil(s) 7.5" x 12" High Q plus bonus 7.5" round Dual Field (Limited Time only) Optional Search Coils Over 100 accessory coils available by White's and others Battery Rechargeable NiMH & AA Operating Time Up to 6 hours Weight 3.5 pounds Additional Technology The TDI was designed specifically to be able to use Minelab SD/GP compatible coils. However, performance can vary and the pulse delay may have to be advanced to compensate for coil differences that result in overload readings. Notes *The TDI is unique in that it can suppress audio responses into two different classes. Targets have a high tone or low tone audio depending on how the target relates to the ground balance setting. In general high conductive targets give a low tone and low conductive targets a high tone. The TDI can be set to allow for one response or the other. See White's TDI Coin Settings for more details on this control. *Notes on Technical Specifications - Detailed notes about the specifications listed in this chart. White's TDI SL High-Q Tan metal detector White's 7.5" x 12" High-Q coil for TDI series White's 7.5" round Dual Field coil for TDI series

Something to watch out for. Extra desiccant pouches in the case my not be a bad idea, along with changing them regularly. http://www.treasurenet.com/forums/white-s/612770-tdi-beach-hunter-already-going-back-repairs.html

Does anyone know any information on the new coil for the TDI SL and if the coil will be available separately? TDI SL is now ... TDI Hi-Q A new high performance coil design for added depth - in two options TAN Part Number: 800-0334-Hi-Q CAMO 800-0334-Camo MSRP: $1199.95 MAP: $1099.00

River Detecting for Gold Nuggets - See who gets the Biggest Nugget. Gold Prospector's Jeff ( Smithsgold ) and Gary ( Two Toes ) Head to the Hills in search of rare Gold Nuggets. Watch and see who gets the most Gold and the Biggest Nugget. SG 010

So there is a used Whites TDI pulsescan detector in my area for sale for $675. It is not an SL so im guessing its an older version. Is there any benefits to owning this detector along with a GPX4800? The price seems good and its close by. Ive also thought i heard that the older TDI were more powerful. I also believe it can use most GPX coils correct? I dont really need it but it seems like a great price for a PI detector.

I did a coil test some time ago using a Tdi Pro OZ, quite a variety of coils involved. Just a bit of information not wanting it to go to waste. The test area was located in the middle of the Golden Triangle in Victoria, Australia. Looking at the images the test site is located on a area that produced large nuggets. Heavily mineralized to give the depth tests some authenticity. Targets were varied as were the coils tested. The Tdi Pro was ground balanced, gain was at 5, conductivity was in ALL, pulse delay was 10. Frequency was set in the middle and the audio was boosted by a Nokia MD-11 external speaker. Only clear repeatable signals were recorded. All targets were buried in the ground sideway from a miners hole, so as not disturb the soil on the surface or above the target. Only the 1 grain ingot and one 0.5 gram gold coin were buried from the surface disturbing the ground. Not sure how useful this is for Tdi SL users, deduct 10% maybe.. Just gives a sense of what is realistic is this one location at that one time with the Pro with the variety of coils available back then. All the best, Karelian

I was just wondering if anyone had used that coil? I have the SPP and I have the large DF plus others but inquiring mind wanted to know about it . At a price they asking it would be in my interest to ask here first. You may ask do I need it and that answer is no ! I’m like a kid in the candy store are a toy store. I Want ! Chuck

I see so many people wanting to up the voltage. I know by doing so also improves sensitivity and overall performance. Maybe someone can tell me why didn’t White’s do the same. My thinking is less load on the electronics makes the detector last longer. At the same time the detector will have a better chance of making it through the warranty . Here’s another can of worms I’ve opened up. Chuck

Hi! after a year of snorkeling with TDI BH I concluded that I can clearly note the sensitivity goes down ones the voltage of my battery pack goes down. Other conclusion was that even at 12.6V the TDI BH is noisy underwater at maximum settings: it reacts to the waves. Thus at the moment I really prefer to have just a stabilized battery pack. For my experiment I took a couple of 21700 5aH Li-Ion cells and a dc-dc booster board. the plan is to get "one hunt" battery pack.

I was looking for battery tray design for my Tdi SL which would allow 4 x 18650 batteries. As luck would have it on the local Prospecting Australia website XLOOX posted a simple mod for a Whites factory battery tray. I don't know how to post links so the full description is to be found in the Prospecting Australia site. Simple cut out the guts of the tray, leaving the original battery connectors with mods on one end and a copper connector on the other. I can fit Panasonic NCR18650B cells, without nipples but with protection. They just fit snuggly. The only issue is closing the lid, you need to cut a channel under the batteries into the base of the tray to allow for this. I'll cover this with a thin carbon fibre sheet and look at using a thinner sheet for the cover also. I will also add something to secure the batteries in position. Just waiting for the postman to deliver my carbon fibre sheet before finishing my own version of XLOOX's design. What I like most is that this is simple and cheap. Must confess I am aware of many different designs, since there have been no reports of smoking Tdi Sl machines I have finally decided to give it a go. All the best, Karelian

Just bought a used TDI Sl from eBay. When the ground balance is off the machine is stable and smooth. The second I turn it on the machine goes crazy. I got a good deal on it. Do I send it back or do I send it in to Whites for repairs? Thoughts?

I did both of Reg Sniff's suggested mods to my 2013 model TDI SL. I also use a 16v battery pack. I was testing it yesterday on pieces of nickel. I buried a 1 gram piece at 6", and a 1.84 gram piece at 10". The TDI saw both with the 7.5"DF coil, and the 8 x6 NF Sadie coil. The 12"DF coil could only see the 1 grammer....same for the Super Pulse 14" 350. The signal on the 1.84 grammer was faint, but repeatable. I'd definitely have dug it in the field. The signal on the 1 grammer was strong with both the Sadie, and the 7.5DF. Could have easily been deeper. Jim

Is it true that some Minelab coils will work on Whites TDI?

This mod has been done at the factory on all SL's made since 2015. So, only applies to earlier models (mine is 2013). It consists of removing the diodes D20, and D21, and capacitor C56. You also have to install a jumper across two of the three diode leads on D21. I'll post a pic showing what I did. The effects of this mod are much more subtle than the sweep speed mod. Maybe a 5-8% gain in sensitivity in the air test on the 1 grain gold bar. But, still some gain, though I had to be paying attention to hear it. This mod should not be undertaken unless you have some serious soldering skills. The components are REALLY tiny....like 1/8" wide, or maybe 3/16" at the very most. Getting the jumper in place is tough...took me 15 minutes of fooling around to get it soldered in. The mod pushed my air test distance on the 1 grainer to 3 1/4", without headphones. Might have done a bit better using the hp's. there is also a slight increase in ground noise to contend with, but nothing that really bothered me. In really ugly ground, it may be worse. We'll see. In the pic, the red triangles are where the diodes were. On D21, you can see the jumper under the lowest leg of the triangle. That jumper is 3/16" long. The straight red line, on the right, is where C56 was located.

Hi folks, so I've ordered myself a TDI SL and spent a few hrs on line trying to find anyone that ships the RnB innovations 14.4v battery to Australia which proved to be an impossible task. So I went on to try and find the highest capacity longest lasting AA batteries for the dry pack and came across the Kentli 1.5v 3000mWh rechargable lithium polimer batteries. I have to say it looks like a brilliant idea but some of the reviews I seen aren't all that great. Now being aware that a lot of reviews are probably BS of one kind or another I have to ask who here has heard of or tried these? The idea of getting a constant 12v in the machine is appealing. Would be good to see some of you electrical gurus out there put them to the test?

Bit the bullet and did the sweep speed mod this morning. Made a huge difference in the acceptable SS. I ran the 1 grain gold bar past the 8 x 6 Sadie coil before doing the mod, and there was a relatively slow, specific sweep speed that gave the best signal. Too fast, and the signal completely disappeared. After the mod, the SS made almost no difference. Fast, slow, the signal was steady. No change in indicated depth in the air test. Threshold was still smooth. I'll post a video of the before/after tests later on. I changed the filter caps (C20, 21) from .47ufd, to ,22ufd. A friend in Florida, who is a civilian tech working for the Navy, was kind enough to send me a few matched pairs of the caps. Without his encouragement, and help, I probably never would have tackled this. Now I'm really glad I did. One tool I'm glad I had was my fly-tying magnifying light. My eyes don't focus like they did when I was young, and that magnification allowed me to see the soldered spots, to be sure I had done a thorough job. Jim

Hello, I'm looking at penetration through schist / slate type bedrock and quartz vein medium mineralized on a 70 deg vert plane, so the end grain is detectable. Fair amount of fracturing from the use of explosives I believe leaving hairline to 1/32 cracking here and there and some larger along the rock wall with 60 or so years of CA. High Sierra weathering on it. . But I'm also looking at what the penetration depth would be for the same material in solid condition further in from the rock face. Anyone have any experience with these conditions? Target is a leafy up to .5 mm thick ribbons and crystalized pockets of gold in, umm, not sure what they're called but they look like flattened bubbles in the quartz coated with crystalized gold inside, the only visible "bubble" is .70" w x 1.7" or so deep, at least according to my fillet knife. Anyone?

I know that most of you guys are not using TDIBH for underwater hunt. TDI is actually horrible for this task 'couse it floats. Youare really suffer to hold it under water.... Horrible, you have to spent a lot of energy to sink down the detector. Somebody uses the coil weight, but in my opinion it is not so good solution as it provokes extra wear on the washers and makes the coil not so hydrodynamic.... My solution is to use lead shots in the 3d printed plastic case as a weight. It works great. The weight is just clipped on the shaft and that's it. No modifications whatsoever are needed. If you hunt on the dry send, just take a weight off. Here are some pictures:

I finally had time to do some testing on the SL, regarding the Ground balance. Here's the result: TDI SL GB TEST 350 Super Pulse coil. battery voltage at start of test = 16.0v Freq. max., Switch in "ALL", Gain MAX, Pulse delay MIN. 1979 US nickel Sweeping side-to-side. The test setup was having the detector vertical, with the coil on top of a 5 gallon bucket to minimize the ground effects. I taped a yardstick to the shaft. I did NOT use headphones, but did repeatedly sweep the nickel to try and get honest results. GB off 13" GB on: 2 14 1/2" 3 15 1/2" 4 15 1/2" 5 15 1/2" 6 14 1/2" 7 to 11 15 1/2" Freq. set to minimum GB off same GB on: 2 14 3/4" 3 14 1/2 4 14 1/2" 5 14 1/2" 6 thru 11 15" Switch to 12"DF coil GB off 17" GB on: 2-5 17" 6-11 16" 12DF with 1 grain gold bar GB off 3 1/4" GB on: 2-11 3 3/4" Both coils with 6 gram men's gold ring: Both coils detected this very close to the same as they did with the nickel. But, turning the GB on and off had very little effect on the depth. It's apparent to me that on some items, my detector is definitely better with the GB on, but set to 2, or minimum. But on larger gold, the GB has little effect. But what effect there is favors having the GB on, but set to minimum. There was only one instance where having the GB off was an improvement. I also tested my NF Sadie 8 x 6, and was surprised to see it was LESS sensitive to the 1 grain gold bar, than the 12"DF. The Sadie struggled to make 3". For me the best coil is the 12"DF, where it can be used. Where it's too cumbersome, I'll go to the Sadie. The Sadie was better than the 7 1/2"DF, and the MJ 5 x 9. I sorta wish I hadn't sold the 7 1/2"DF...I'd like to test it more. I also tested a 1" thick x 4" diameter hunk of aluminum, with a 1 1/4" hole through the center. Neither coil could detect it near as well as they did the nickel. Jim

I have never experienced this on any version of the TDI. The “ground balance off” mode should be the pure unfiltered signal. Engaging the ground balance engages a filter which reduces the air test results in a properly functioning TDI. The only reason the TDI has the ability to turn off the ground balance is to get this extra depth back, as has been highlighted in numerous online posts and videos. The manual says air test depth increases with the ground balance shut off. What you are saying simply makes no sense from a pure electronics standpoint and how the ground balance functions. If a TDI loses depth in air tests when the ground balance is shut off then in my opinion it is not working properly.

At one time I bookmarked or downloaded photo and text instructions on modifying the TDI/SPP to effectively turn it into a TDI/SL. I can't seem to find it. Anyone here know the link(s)?

Is there anywhere on this site that has the research or post made from Reg Sniff pertaining to TDI depth in relation to battery voltage? I remember somewhere that stated the reason the original TDI had greater depth capabilities was the increased voltage of the batteries not necessarily the model number. It also had information in relations to voltage limits/performance issues. Just thought I'd ask.

I have had my TDI BH for 2 months now and was wondering if a mono coil would get more depth and less sensitivity to small targets namely lead bullets than the stock Dual Field. Where I hunt there are a lot and they sound good but fall through the holes in my scoop { 10 mm}

I just purchased a TDI SL special edition. The unit came with the Miner John 8x12". It seems to do OK at the beach but leaves me wondering if another coil could do better. Not overly concerned about finding all the tiny bits. Also I find the walking pace when using the 12" mono, for complete coverage, is a challenge for me on the beach.