RickUK Posted January 26, 2020 Share Posted January 26, 2020 Outstanding video and general observations regarding all 3 machines,i own and use a TDI Pro with a selection of coils but the main one that i use is the Coiltek 14x9 Mono which is similar to the Digger coil which i wish i had also added to my Jimmy Sierra closing down list of coils.I bought 3 rom him a about 2-3 years back including the monster 20'' Sierra Grande. Mine is totally stock from the factory and although i was tempted to get it tweaked it was still in warranty at the time. Missed your indepth coil comparison testing on FindsMall as that was possibly the best testing of any TDI Pr/sl of all time,meticulous and precise information was provided. Thanks again for providing some further information on the TDI range of detectors. 3 Link to comment Share on other sites More sharing options...
karelian Posted January 27, 2020 Author Share Posted January 27, 2020 RickUk, I suspect that there are a number of factors a work that determine depth between the machines. First as a simple air test, with the ground balance OFF, we are focused only on threshold and sensitivity. Ground conditions are usually a huge factor.. but in air tests we can dismiss this, for now. This will play a big part in the later in ground testing.. So the modified Pro has a smoother threshold, making it easier for us to distinguish target response. Secondly the more pleasant threshold makes for a more 'pleasant' detecting experience, less concentration required, less fatigue etc. Finally I believe there is a small but noticeable improvement in sensitivity. Combining all of the above the machine could be regarded as outperforming the standard machine, by a small margin in regards to depth, but significantly more pleasant to use. Finally the modified unit can advance the gain a little further before it becomes a bit unstable. Not sure if it is the modifications or a common variable between all Tdi Pro detectors. Rare to find detectors that settle gain on the same point on the dial. I had two XL PRO machines and they were identical, but one could push gain a little higher than the other, with almost identical depth and sensitivity.. question remains unanswered? After years of using the standard Pro my brain is hardwired to 'work with' the warbles and I can easily distinguish target reponses. I work at a certain sweep speed which I believe is optimal, lots of coil control, know my machine and more.. I am immune to the warbles, others could easily find them distracting to say the least. Another reason why I have a Tdi Sl as a loaner machine, light and balanced, decent performance with the battery upgrade and that super clear and stable threshold.. Our detectors are what they are, so it is up to us to work out how to get the most out of them, normally we have to adapt to the machine since machines cannot adapt to our way of doing things. The modifications on this Tdi Pro are I guess a way of fixing what many would regard as shortcomings in the standard machine and to some extent they have been successful. 5 Link to comment Share on other sites More sharing options...
karelian Posted January 27, 2020 Author Share Posted January 27, 2020 Sorry about the dove in the background, a little bit of native wildlife intruding.. Just the Tdi Sl, followed by the standard machine with Anderson shaft and finally the modified Pro. Threshold and target response from a 1 grain gold ingot, just to flesh out some detail. 3 1 Link to comment Share on other sites More sharing options...
Jim in Idaho Posted January 27, 2020 Share Posted January 27, 2020 My SL is much more like the signal you're getting from the Pro's. Same 1 grain bar. It does soften a little with the MJ 8 x 12, however. I was trying mine indoors, and that makes the threshold noisier. Which coils were you using, Mike? Jim Link to comment Share on other sites More sharing options...
karelian Posted January 27, 2020 Author Share Posted January 27, 2020 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.. 3 Link to comment Share on other sites More sharing options...
Jim in Idaho Posted January 28, 2020 Share Posted January 28, 2020 That Sadie is a great coil, Mike. My SL is definitely louder than yours, with that Sadie and the 1 grain bar really looking forward to the in-the-ground tests!. Also the results with that 4 x6. Would you believe I also have a 31/4" x 6 1/4" Razorback for mine? I'm guessing those are the actual dimensions of what you're calling a 4 x 6? I have yet to try it. Jim 1 Link to comment Share on other sites More sharing options...
karelian Posted January 28, 2020 Author Share Posted January 28, 2020 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.. 5 Link to comment Share on other sites More sharing options...
Steve Herschbach Posted January 28, 2020 Share Posted January 28, 2020 I had no idea they had made a 4” x 6” coil for the TDI... that’s the first one I recall seeing. Link to comment Share on other sites More sharing options...
Jim in Idaho Posted January 28, 2020 Share Posted January 28, 2020 10 hours ago, Steve Herschbach said: I had no idea they had made a 4” x 6” coil for the TDI... that’s the first one I recall seeing. I was surprised myself, Steve. Found it on Ebay last summer...Brand new. As I recall, it cost me $50. (sometimes you get lucky...ha!) Has a nice, sharp signal on the 1 grain bar at 2 1/2" Mine is identical to the bottom pic on Karelian's post. Jim 2 Link to comment Share on other sites More sharing options...
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