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View Full Version : White's TDI SL

Steve Herschbach
08-14-2011, 12:40 PM

When I was down in Nevada in June I was able to spend a couple days running a prototype of a new White's TDI model - the TDI SL

The new unit addresses several issues. First and foremost, weight. The original TDI weighs 5.6 lbs with battery. The new SL is available with either the 7.5" coil or 12" coil as standard. The weight with the 7.5" coil is only 3 lbs and with the 12" coil 3.5 lbs. I found the weight and balance with the 7.5" coil to be a real pleasure at 2.6 lbs lighter than the original TDI. The SL is not set up to hip or chest mount but there is little need because it is so light. If it was desired though it would be an easy modification as there are no wires in the rod. Replace a couple rivets with bolts and it could be belt or chest mounted.

Some of the weight savings is that the SL comes with the NiMH rechargeable battery and charger used in the V3i and the same AA battery pack as used in the GMT, MXT, etc. The Lithium-Ion batteries were heavier and presented shipping problems due to restrictions on shipping by air. The downside is the SL will suck up a set of AA batteries in about 5 hours. When I get my SL I will get a second NiMH battery so I can run the first half of a day on one then swap to the second for later in the day. The AA pack is better for an emergency backup unless you detect a lot less than I do. I went through 24 AA batteries in two days.

Still, I much prefer this to the Li-Ion batteries. The reduction in weight on my arm is worth carrying a spare battery pack in my pouch. And since the SL costs much less without the Li-Ion batteries you can afford to get an extra rechargeable pack or two and still be money ahead. Or get rechargeables to use in the AA pack.


The original TDI has a very uneven threshold. Much work went into getting a smooth threshold on the SL. This has been done though in theory a bit of depth may have been sacrificed. But unless your ear could pick a faint signal out of the noisy threshold on the original TDI I doubt most people can get that extra depth. I much prefer a smooth threshold that allows me to easily hear a faint signal. The SL has a threshold that generally is rock solid though in some ground it can be more variable.

There is currently a mistake on the White's page at http://whiteselectronics.com/tdisl.html that describes the unit as having both coarse and fine ground balance controls. It does not. It has a single one turn ground balance. I would have preferred a multiple-turn control for finer tuning but the decision to eliminate the GB On/Off toggle switch and incorporate that function into the GB knob precludes that idea. The Power On/Off toggle has also been eliminated and instead incorporated into the Gain knob. This all ends up being a control set more familiar to users of the MXT or GMT.


All existing TDI coils are compatible with the SL.

The bottom line for me is simple. This unit is so much lighter and compact compared to the original TDI that I immediately sold my old TDI so I can replace it with an SL. Multiple tests of the SL against the TDI or TDI Pro with multiple people and machines involved saw the majority thinking the original TDI and Pro as have a slight edge in performance. For me that is overshadowed by the weight and smoother threshold. I have to enjoy myself when detecting and I really enjoyed running the SL.

The more compact design offers hope for a waterproof version. No, I do not have information that leads me to suspect we may see a waterproof TDI. But I do keep trying to get White's to make one and the SL makes the case easier to argue.

The TDI SL with 7.5" Dual Field coil, NiMH battery and charger, Plus AA battery pack has an MSRP of $1249.00 and the SL with 12" Dual Field coil instead of the 7.5" is $1299.00

little man
08-14-2011, 01:44 PM
THANK STEVE we been reading all we can about it looking for more test on it we going to hold off right now on getting one we will be keeping my TDI Pro we love that thing we mite get one this spring if thing go ok like you said if you can't here a target then all the dept in the world not going to help

Steve Herschbach
08-14-2011, 02:00 PM
Hi little man,

I am not advocating anyone give up their TDI or TDI Pro for the TDI SL. The Pro is still the flagship unit. It is a personal thing on my part as of late that weight matters a great deal to me. The only reason you should consider an SL is if you can get your hands on one and try it first. That is what I did and so I decided to make the switch. You may decide just the opposite given the chance. Wait for tests from regular Joe User. Guys like me are great for getting out good technical information and advice but it is wise to ignore anyone early on like myself who has connections to the industry and wait for multiple reviews from regular users to come in.

Steve Herschbach
08-14-2011, 02:10 PM
I finally got to meet Digger Bob in Nevada. Nice guy and a far more careful tester of detectors than I am. I am pretty casual. I use it, and if I like it, I'm done. Guys like Digger compare every tiny aspect to the nth degree. So in many ways my technical knowledge is pretty weak compared to guys like Digger since I pretty much believe at the end of the day it is all about getting over the target. I am not a tuning wizard. Digger is.

Anyway, here is a great video from Digger Bob about the SL, with perhaps the best thing illustrated being the smoothness of the threshold. Check it out.


little man
08-14-2011, 04:59 PM
we been keep up BOB and REG and two three more on it we have a little noise on mine TDI Pro but can run up to 10 in a lot place we hit the old site that they say are hunt out and the old house place we can find here so finds we got two week a go the bayonet is broke it doesent look that way it the PIC. we still like to get my hand on one I thank it would get so of the target that we are miss because of the noise we hunt in all. Coal token around here was made of brass and alum copper and pot metal as we call it they use then for 60 year ther got to be high dollars and the SL is liter would be a + for me