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Whites Tdi Pro Stock Vs Whites Tdi Pro Modified


karelian

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The passing of a friend unfortunately has led to me taking ownership of a modified Tdi Pro. My machine is mounted on an Anderson shaft and is factory spec. My old mate had his machine modified to smooth out the threshold and to add some sensitivity. The specifics related to the modifications are not known by me, other than that they were conducted by 'Luke'..Oz Digger.. This happened some time ago. So the modified machine is probably not a keeper, I don't want two Tdi Pro machines.. The opportunity to do a comparison cannot and should not be ignored. 

My intention is to focus on small gold performance, the threshold smoothness, the ability to use gain, basic performance and handling characteristics  under different circumstances. The machines will use the same fully charged battery pack, same coil, same targets, same test location and conditions on the same day etc. Trying to minimise external variations. I'll start with the usual useless air test. Later I'll follow up with in ground testing on the actual goldfields in mineralized soil. Test coils will be with a small coil and a large coil. Targets will be gold only. The 1 grain ingot, the half gram gold coin, a half sovereign gold coin. Some real small sub gram nuggets to see how small we can go.. There is a process involved so I'll take my time and do it right.  Any specific questions or suggestions, speak now or forever hold you peace.. I'm only doing this once. Once it sold it will be too late to revisit.. 

All the best.

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phrunt, the answer is the modified unit is a goner, long term I'll keep the standard machine, regardless of the results. The reason is I know the history of the standard unit and have looked after it since near new. I can vouch for its history etc if I ever decide to sell.

Do you keep the car with service books and history, or the one with an aftermarket turbo..... 

I've been asked to do a video showing the differences in threshold, I'll show the Tdi SL, modified Pro and standard Pro. It won't be very exciting but it may be informative.. At least I used a DSLR, external Rode microphone and a decent Miller tripod.. no music, just threshold hummmmmmmmm...

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I'll do better next time, titles would be nice. Clearly first machine is a Tdi Sl, second is the modified Pro followed last by the standard Tdi Pro with Anderson carbon fibre shaft.. The modified machine clearly has smoother audio than the standard machine which exhibits that atypical warble.. more to come..

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Good video. Nice to hear those differences, at last. First time I've heard the threshold on the Big box units.

JIm

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That warble in the unmodded Pro is what drove me to distraction in both my original and Pro machines. For me that particular mod was a life saver.

Karelian, I believe the second mod in the modded Pro is to increase sensitivity to small gold. That may be worth looking into during your testing. And for me if the turbo vehicle met my needs better than the stocker, the stocker would be the goner. Looking forward to your test results. Thanks for doing the testing.

 

Mike

 

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Tested small gold sensitivity and ability on porous gold using Coiltek Tdi 6" mono coil.  Both machines were tested on the one grain ingot, the modified unit beat the standard unit by 5mm or half a centimetre. I suspect the smoother threshold makes it easier to pick up the target response but even taking that into account it was marginal. The quartz infused and partially porous gold sample is a challenge for PI machines, from testing I know the small Coiltek Tdi coil and the Sadie will pick it up. The standard machine managed 4 cm whilst the modified Pro came in at 5 cm, marginal but still a 20% advantage. The unstable threshold works against the standard machine, I only record target depth as that which is repeatable and in my mind stands out as a target.. Threshold seems to be key here, actual sensitivity is very close, just a small fraction in favour of the modified machine. Also the ability to advance the gain or sensitivity before instability was checked. A clear advantage to the modified machine. Where the standard machine peaked at six, I got the modified unit to eight. So the threshold component transcends into a bit more gain, an advantage in detecting whispers, with a bit extra sensitivity. Tested were conducted with the same battery in both machines, same time and location etc. These were air tests to determine sensitivity and threshold only. One final air test to follow before actual ground testing in the goldfields. 

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Same test as above, changed the coil to the Jimmy Sierra Digger 14 x 8 mono, by Miner John. Gain was less this time, only got the standard machine to 5 and the modified machine to 7. Suspect coil size plays a part in this.

Standard Pro got 1 grain 8cm,  0.5g gold coin 31cm, Half Sovereign 42cm.

Modified Pro        1 grain 9cm, 0.5g gold coin 33cm, Half Sovereign 45cm.

Both machines with ground balance OFF, pulse at 10, conductivity on ALL.

So a pattern of behaviour is showing, the modified machine has a smoother threshold, it allows a couple points of extra gain and has a fraction more depth. This pattern seems consistent regardless of the size of target or size of coil used.. It will be a while before the next test. In ground testing on the goldfields, weather, fires and other factors will determine when.. hopefully soon.

Mike T, performance is one thing but that smoother threshold certainly makes the modified unit more pleasant to use, if using headphones to drown out the sounds of the oceans, wind etc, it can make all the difference in terms of concentration, ability to pick up on small variations in audio or whispers etc.  

The Tdi Sl has a beautiful steady threshold hum, music to my ears, with the 16v battery pack there is still a small performance deficit.. but it is a fun, super light and a well balance machine to swing.

On the standard unit I sometimes turn threshold to just silent, makes for more pleasant experience with headphones on the beach, with a small loss of performance. 

 

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I'm a bit confused.  Does the quieter threshold improve detection depth when the gains on the two Pro's are the same?  Or is it simply that the ability to increase the gain on the modded unit results in more depth after increasing the gain (and keeping the threshhold wobble the same)?

Thanks for the tests and I look forward to the continuation.

 

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Karelian, I agree completely with your comments about the smooth threshold. I am able to run both the original and Pro units wide open on gain and threshold with no warble at all. Makes for a very satisfying detecting experience.

Mike

 

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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. 

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