Mark Gillespie

I'm with you Steve.  For some strange reason I'm thinking they will wait until someone released a detector that grabs our interest.  I know 1st Texas wants to release a perfect machine (nothing is perfect) out of the gate but there will be a point where people will quit waiting and move on.  As I recall a couple years ago they, (presumably a leak of 2 new detectors under development, "CZX" well I waited until the Equinox was released and jumped on board.  And I'm glad I did.  If they wait too long, it will cost them. 

You know, Minelab listens to what is going on and it wouldn't surprise me if they don't release something to pickup part of that market before 1st Texas.

I want to post and give a big thanks to Jim for all your help with my battery pack.

  All your suggestions and encouragement were much needed.

Great find, never dug a seated.

I'm speechless, wow.

I'm presently pursuing if there are any revisions that might explain performance differences between the SL version of the TDI.  This is my board.

Thanks for taking the time to test and post your results.

I did notice your starting voltage was 16, this obviously tends to prove, more voltage, more depth capability. 

Your nickel test basically states that the nickel detection range does not regrade when GB is switched on, until GB is above 6, using the 12" dual field coil.  Very similar to my results with the US nickel.  You gain quite a bit over my unit using the same settings, very impressive. 
 

16 hours ago, Jim in Idaho said:

Switch to 12"DF coil

GB off    17"

GB on:

2-5       17"

6-11     16"

It would be very interesting to see the same test settings using a US dime and quarter.

I think you should notice a difference using these high conductors. 

Can you share how you came about the 16v battery pack?

6 minutes ago, Steve Herschbach said:

Finally, I think you have brought clarity to this issue Mark. It is not just ground balance on or off.... but where the ground balance is set in relation to the target type. Your tests confirm exactly what I would expect. At some ground balance settings there is no difference of import, and at other settings a massive difference. Excellent work and thank you very much. I guess it now falls back on others to compare and confirm.

I do feel like "duh, I should have seen that"! 

To be honest I'm kind of ashamed I had not remembered that.  I knew better but for some odd reason it didn't click when I tested the first time.

On ‎5‎/‎17‎/‎2019 at 10:05 PM, Mark Gillespie said:

My SL was manufactured in 2014.

Rechargeable battery pack was 11.62 v

Fresh set of alkaline batteries in the Alkaline battery pack 12.61v

I re-tested my SL this evening using the above battery packs and the 12" dual field coil.

I saw, absolutely no air test difference between ground balance on and ground balance off.

So, it would be obvious if I was hunting at the beach, to use the GB on feature over the pure PI function of GB off.  At least I'd have some control over the iron and still hear the gold. 

Now I'd like to see other SL users post test results.

Curious to see a date relationship to the depth reduction of ground balance on.

 

I guess I should start by making a few statements:

If driving along you come up to a stop light and its red, what will you do?
You stop, right?  Natural habit of good driving behavior.  It’s late at night and you get up to use the bathroom, the room is totally dark, you can’t see anything, and what will you do?  Turn on some kind of light so you don’t fall, right? 

Now, I’ve said all this to make a statement about using my PI machine.  Typically I charge my battery pack prior to leaving the house and off I go.  When I reach my hunt site, I power up the detector, set gain to about 8, make sure the ground balance is somewhere around 7 ½ to 8, set pulse delay to 10, set the conductive switch to all and away I go.  Now, when hunting with my TDI this is a natural procedure for me, to insure these settings are checked before starting my hunt. 

Now I must correct a statement I made in response to ground balance off verses ground balance on.

Quote: “I saw, absolutely no air test difference between ground balance on and ground balance off.”

This answer is both true and false but I failed to perform one adjustment when I performed my test. 

The following is actual test results of ground balance off verses ground balance on.  The results plainly indicate there is a huge depth reduction (-2”) when the ground balance is first turned on up to about GB 6 ½ with both the dime and quarter but not with a nickel. At GB setting >= 6 ½ depth (air test is equal to or exceeds the GB off settings.  I must admit I was not adjusting the GB to these lower numbers when I made the above statement and I greatly want to apologize for the oversight.

Key note on the graphs:

Test were done with a battery voltage of 11.5 as noted on each graph.

GB Value 0 = Ground Balance Off

GB Value 1 = Ground Balance Minimum

USGA1007.pdf

23 hours ago, gflores71 said:

I spoke with Reg many times about making changes to my TDI-SL

We also exchanged many emails, I do still have them. He describes the changes and purpose and also included images of the circuit board and locations. 

Anyone interested can shoot me an email and I will forward. 
I can also copy them and post them here but would like to know if Reg is OK with it first.

Gilbert

gflores71@hotmail.com

Thanks for the information.  Interesting information.

11 hours ago, Tony said:

Hello Mark

Gain at max and delay at 10us......plus the extra voltage of course. This is where the extra 1 to 2 inches comes from over the standard pack. I leave the frequency at the 12 position. Stock coil. Turn the threshold down low.....a fraction below where it is heard AND increase the volume.

Tony

That is very impressive results from your machine.  Mine will struggle to get 12 1/2" on a nickel and that is at best with the 12" stock coil, but of course I have a regular SL built in 2014.  I have wondered about the extra voltage from a new battery pack, but I'm happy for you.

I have hunted many sites that exhibit harsh EMI on the Equinox.  At these sites, if after performing a noise cancel in the conventional way and not seeing good results, I'll lay the coil flat on a clean ground area and do a noise cancel.  If at that point the machine doesn't quieten down to my satisfaction I'll listen to each channel and pick the one with the least "noticeable" EMI.  Now, If I'm still not happy I'll reduce the sensitivity a couple numbers at a time.   

Final note, in most cases, as long as the coil is in motion the machine will run quiet but when I stop to dig a target the EMI will ramp up.  I know this is not a documented noise cancel procedure, but it works.  Give it a try.  Don't get frustrated and give up. 

After spending many enjoyable hours of testing my TDI SL I'm starting to see some of the true advantages the AQ will have over my SL at the beach.  Comparing written accounts "forums" of the AQ's capabilities to my "known" TDI experiences, it's becoming quite evident the TDI will fall quickly behind in the category of a beach hunter.  Oh, there is so much to know about this new machine.  For sure, there will be many unique "combination settings" discovered once the machine is released to general users.  Exciting times ahead.

On ‎9‎/‎15‎/‎2018 at 2:53 AM, Tony said:

Just got back from the beach....in one word.........awesome. Some observations;

It is the deepest detector I have ever used on the beach (in the past 25 years) by running the higher voltage pack.

It is the first time I have ever detected (with any detector, including the Minelab PI's) my gold wedding ring at a measured/buried 18" deep.

The US nickel can be heard at 16" in buried wet sand...but with GB OFF. With GB ON it drops to 12"-13" !

My machine is much deeper with GB OFF across all targets.....the rock solid threshold with GB OFF is unbelievable with no loss of sensitivity.

Even with the coil swept through shallow salt water at max gain and 10us......it is so smooth. I don't know how White's have done it....maybe a new batch of the latest flux capacitors......

I tried with GB on but in clean white sand, there was no perfect GB....it was close but just a slight positive signal as the coil was lowered to the ground...but the depth loss was significant with GB on and slight falsing with higher GAIN. None of this is a problem with GB OFF.

Tony

Very interesting depth post.  US nickel at 16" in the wet salt sand area.  My SL can't come close to that even with the stock 12" dual field coil.  It would be interesting to know a little more on the subject.

Stock 12" coil?

Pulse delay, 10?

Gain?

Frequency offset -, 0, +?

Battery voltage?

Very sad, they made some of the very best audio machines I've ever used.  Very distinctive audio ID.  Loved the Tejon.

Add a battery holder and all is good to start.  No more soldering wires to battery ends.

https://www.aliexpress.com/

Nice batteries can be found in used laptop battery packs. I found 6, nice batteries inside a HP laptop battery pack. All test good and can provide some nice project batteries.
Some of the best on the market can be found in laptop batteries.  A trip to the local computer repair shop can usually find some nice discarded batteries cheap.

Sadly yes, I'm actually concerned for White's.

My SL was manufactured in 2014.

Rechargeable battery pack was 11.62 v

Fresh set of alkaline batteries in the Alkaline battery pack 12.61v

I re-tested my SL this evening using the above battery packs and the 12" dual field coil.

I saw, absolutely no air test difference between ground balance on and ground balance off.

So, it would be obvious if I was hunting at the beach, to use the GB on feature over the pure PI function of GB off.  At least I'd have some control over the iron and still hear the gold. 

Now I'd like to see other SL users post test results.

Curious to see a date relationship to the depth reduction of ground balance on.

Carl on the Getech just posted air test distances.

13+" all metal, 1-2" less in GB.

I'm assuming this is with the stock 12" dual field coil and a nickel.

This is right in line with what I've saw with the exception of GB on doesn't reduce my depth.  I'll check again and confirm. 

1 hour ago, auminesweeper said:

Jim, Mine was built in 2013 as well, but none the less mine did not show any depth advantage with the GB switched Off,  all I noticed was that smoothing effect that the TDI pro does with the GB off my SL did it when the GB was On which means it was trying to balance out the target. 

Well we have 3 for 3 that all show zero depth increase with the GB off, which is making me start to doubt the many posts I have read claiming that there is a depth increase with the GB Off, Yes there is with the TDI Pro but Not the SL.

auminesweeper

Would it be possible for you to do an air test similar to the settings I mentioned above, using a nickel and quarter?

I posted the same information on Carl's Getech site and he stated not having any idea about the GB question I posted.  Makes me wonder, if White's knew something had changed but never revealed it to the users.  Else I can't imagine Carl not having an answer but a reply, "Sorry, no idea what might be going on."  I would bet Reg would have an answer.

I guess the main thing I'm trying to figure out is why my machine's performance does not increase when ground balance is turned off.  100% sure of what I'm seeing now.  I sent Carl a message but he's not replied and if anyone would know why, what, how on what I'm seeing, it might be him.

I did another detailed test last night, using the TDI SL with the 7 ½” dual field coil with a freshly charged battery pack.

1. Ground balance on and set to 7 ½, conductive switch set to all, gain max, smooth, low volume threshold.  Results, two different tones, high tone for a nickel and low tone for a quarter.  Air test, 11” for the nickel and 9 ½” for the quarter.

1. Same settings but turning ground balance off, counter clock wise until it clicks off, conductive switch still set to all, one tone for both the nickel and quarter.  Air test, 11” for the nickel and 9 ½” for the quarter.

The same results were also noted using both the 12” dual field and the super pulse 350, no air test increase when switching from GB on to GB off.

It is obvious this machine is different from others whom state gaining from 1-2” additional air test distance with the ground balance off. 

The manual also states, " Turning the Ground Balance to the OFF position disables the ground balance and TDI will run as a straight PI detector. This gives a slight improvement in depth but, of course, will respond to mineralization and eliminates the ability to discern conductivities.  "

All this being said, there must be at least two variations of the SL.  You would never get White's to comment on this, for sure.

I'm guessing you are correct.  I'd guess the TDI's changed over time, as components fell to the discontinued status, substitutions were made.  I'm doubting White's will provide any information but I'd still like to know why there are so many variations with the machine.

10 hours ago, Jim in Idaho said:

I just tested the voltage output on mine, and it tracks perfectly with the battery pack voltage. With the 4 cell pack at 14.53v, I got 6.29v of output to the coil, and with the 3cell pack at 12.03v, I got 5.3v of output. So the higher battery voltage does push more current through the coil on mine. Thus a stronger magnetic pulse going into the ground. I figured out the correct terminals by using my inductance meter to see which terminals showed a coil across them. Looking at the connector, with the gap at the bottom, the correct terminals are the second from the left, and the second from the right.

 Inductance on both the NF Sadie 8 x 6, and the Super Pulse 350 14 x 9 showed 1.4 micro-henrys.

Jim

Very interesting Jim. 

What device are you using to measure the voltage? 

I was using a calibrated Fluke True RMS and was measuring directly from the TX output on the board.

All this said I noticed a very large difference in voltage from a complete counter clockwise frequency offset to a complete clockwise setting.  Even though there was a large difference in output voltage I didn't see any extra air test advantage.  The manual states this feature function is "This control makes small adjustments to the transmitter pulse rate".  I was guessing a small shift in the frequencies and wasn't expecting the voltage span.

Now you have me to wondering if the inductance of my coils might be different than yours because if the inductance is quite a bit larger (value) that would limit the current flow considerably.

On ‎5‎/‎14‎/‎2019 at 9:11 PM, Mark Gillespie said:

White's TDI SL, manufactured 2014, pulse delay 10
Air Test	Freshly Charged Battery Pack
			GB OFF		GB OFF		GB ON MINIMUM		GB ON MAXIMUM
			GAIN MAX		GAIN 8		GAIN MAX		GAIN 8
7 1/2" Dual Field Coil			11"		11"		11"		11"
Super Pulse 350			11 1/2"		11 1/2"		11 1/2"		11 1/2"
12" Dual Field Coil			13"		13"		13"		13"
To be honest I'm kind of disappointed
Very smooth threshold In ground performance may be different

Sorry for the mistake, the first post had the 7 1/2" coil only getting 7 1/2" but it's actually 11" with a nickel.