70 vs 705 for gold nuggets.

[David]

http://www.nuggethunting.com/forums/index.php?showtopic=6087

Allen in MT wrote, "From what I see the difference between the xterra 70 and 705 is as different as night and day, as with the processor being a whole lot faster and when you balance out a hot rock with most machines you will loose depth, but the 705 will average out the hot rock and won't loose depth. A small flake of gold that can't be heard with the 70 will be picked up with the 705. The 705 is a whole different ball game than the 70, using the ellipitical coil
Still playing with it.
Allen"

Very interesting thread and statement above. I thought the 70's and 705's Tracking and Ground Balance were indectically the same and the only difference in the Ground Balancing between the 70 and 705 was the Off-Set Tracking(+15 to -15) for a positive and negative setting? What Allen has wrote above has got me puzzled? Any comments on this please.

 

[thedeserttortoise]

He may have something there David. In that comparison chart its says improved performance in a couple of places. I wonder if the Minelab people just used the same hardware and reconfigured the software or if they did a complete rebuild with new cpu/circuits and software. I'd like to see the builders specs.... I know, good luck. I still cant beat my X70 for sensitivity on small goodies. I foreever picking up single stramds of super fine wire about an 1/4 inch or so long. The diameter of these strands is about 1/2 the size of the lines in this type. I don't know how they got out in the gold fields but there's always a few in each days digs. Lots of hobnails from the soles of the old miners boots too. I'll say one more thing though. After buying all these coils for the Xterra I'll be damned if I'm going to buy another controler to hunt gold better. Even in the article you found, one brand and name comes up consistantly as the BEST vlf gold finder.....ah! Tesero Lobo Super Traq. It seems to handle any soil and ground ballance conditions thrown its way. And its a heck of a lot cheaper than the 705 and carrys a lifetime warranty too. If Minelab offered the upgraded controler at a discount,,,, I might bite. But everywhere I turn, everyone that finds gold, they all say the Tesero is it. Even the main blog in the article you quoted rated the Tesoro as the tops it seemed. And, besides. I'll add additional functionality to my arsenal without duplicating equiptment.


This is a quote from the site you linked too above...I believe NuggetHunting.com. This is one paragraph from a individual up at Moore Creek in Alaska...

What we found was units that can be set to reject hot rocks have had the most success at Moore Creek. I have found a lot of gold there with the Fisher Gold Bug 2 set in iron disc mode, as the hot rocks are totally rejected or at most just pop or click. The Tesoro Lobo has over time proven itself to be possibly the best performer when put in disc mode and with the disc set at about 1.5 to reject the rocks. The MXT does well in coin mode with just enough disc cranked in to reject the rocks, or in relic mode with key forward, which nulls iron signals.

 

[David]

Thanks again! It is funny that no one knows if there was another improvement to the Tracking from the 70 to the 705, besides and other than the Off-Set.

Yes our X-70's with the 5x10 DD HF should be just find to use for small gold. I cannot see how the X-705 is greatly better? Only minorly better IMO. Yes the Off-Set Tracking GB is an advantage but not a great big advantage IMO. It is like we use to do with manual GB metal detectors(like how the Gold Bug II and Vaquero-Tejon are set up now) many years ago, in All-Metal mode by setting the GB a little to the positive side(the sound volume increases) on the downward pump of the coil when manual GBing. Instead of no change in sound volume, which is how it is normally run.

 

[Digger]

Being a detectorholic, I bought the 705 so that I could make direct comparisons to my X-70. I wasn't interested in a backlight as I don't hunt at night..... I wasn't interested in another Pattern mode because I hunt in all metal most of the time. (for the times I don't, Patterns are so easy to modify that adding a fourth made little sense). I do like the new Pinpoint Sizing mode as it allows me to size up the target similar to the way I use Prospecting mode on my X-70. Since it is a "Pinpoint" mode, it continues to provide visual TID (Prospecting mode does not provide visual TID). But the "feature" that attracted my attention most was the GB Tracking Offset. I do offset my X-70 a couple digits positive when I hunt. Although it does seem to make the detector a bit more chattery, I am convinced that it provides me with more depth. On the X-70, I would set my GB automatically, recheck in manually and then lower the GB phase number a couple points. I did not use the Tracking feature on my X-70 because it would continually set the GB phase "as programmed" and not provide me with the positive phase that I am wanted. I am still not a big fan of tracking as many of the sites I hunt are littered with small bits of iron and I don't want the detector to get fooled into thinking that those pieces of iron are actually the soil matrix. But if I find a place that is not littered with a common form or metallic trash, I like the fact that I am able to maintain my "positive setting" while in the tracking offset mode.

As to depth differences between the X-70 and 705......... it is becoming more apparent to me that my 705 does have more depth capability than my X-70. Nothing scientific, mind you. But I have ran "side by side" tests between the two detectors, using the same exact coil, and the 705 will provide somewhere between 10% -15% more depth. Can that be attributed to a more advanced Sensitivity scale? Is it because the 705 provides a definitive "whisper" signal on deep targets that the X-70 just can't provide a signal on? Can it be attributed to the "improved performance" of the GB electronics? Or is it simply a comparison of my X-70 and my 705? Who knows? All I know is that my 705 will hunt deeper than my X-70, by between 10% -15%. And I am hearing deep whisper signals on the 705 that I can't hear on the X-70. As with all comparative analysis, your mileage may vary! JMHO HH Randy

P.S. I still carry both the X-70 and the 705. I keep the 9-inch concentric at 3 kHz on the 705, with the 6-inch DD at 18.75 kHz on the 70. I figure if the 705 does go deeper, just as well give it the maximum opportunity to prove itself with the 3 kHz coil. Although the 6-inch is not a slouch by any stretch of the imagination, separation of targets is the primary reason I use it. Ya know, I use to think that changing coils was easiest when you had an extra lower rod. Now I find that having these two machines (equipped with these two coils) is the way to go!

 

[Jack Flynn]

Is it because the 705 provides a definitive "whisper" signal on deep targets that the X-70 just can't provide a signal on?

I heard several of those nice light high toned whisper signals the last hunt I went on in S.C. I dug several of them but in a community park setting I prefer to just not break out the groundshark and backhoe away. When the lesche trowel is all the way in the hole and I can still get a signal I leave it for the bulldoziers. I'm glad I read this post, it seems to verify what I thought.

 

[Digger]

I have no scientific evidence to support my theory......afterall Minelab is pretty tight lipped when it comes to sharing technical specs on their detectors. But when I test the X-70 and the X-705 head to head, using the same coil (not just the same freq and size, but the same coil) I am able to hear a definite whisper tone with the 705 on targets that are just out of reach of the X-70. I am convinced that the audio tone on the X-70 is "go or no-go" where as the audio tone on the 705 fades away to nothing. Thus, there is a certain depth that provides a "whisper" tone on the 705 that I am convinced I would have missed with he X-70. Again, nothing scientific. Just my opinion based on my tests in my soil. HH Randy