Vallon VMH3CS Mine Detector

[Ferric Toes]

The days of easy pickings for the average person hunting for gold on known ground are gone. Many potential buyers are in reality, inveterate gamblers. After putting in much time on research for likely locations, and expending considerable fuel and precious free time to get to the chosen spot, they are not going to further stack the already high odds against - by use of a product with inferior detection ability.
It seems a certain manufacturer cottoned onto this. If you go to any of the forums/websites where photos, videos and narratives of gold finds are posted, you will see what make and model predominates. And more importantly, what size of gold is predominately found.

Loaming is a well known method for zeroing in on the source. Being able to see and count the specks in the pan indicates whether its time to move to new ground, or keep looking. Same with gold detecting, its a form of electronic loaming. Those small, or weak and faint targets are the breadcrumbs that lead to the heart-pounding "big-uns".

The make of gold detectors that predominate, is of course Minelab.(not sure why that is a taboo word here). I would be surprised if that were not the case, as they are based in Adelaide, which is within easy reach of what were prolific goldfields in extremely bad ground from a metal detector's point of view. Developing a detector to handle severely iron mineralised ground which is virtually on your doorstep is a huge advantage. They thought they had bad ground in the US but from samples I have tested, Oz ground can be 10x worse in terms of the signal it presents to the detector.

Minelab certainly cottoned on to this and designed the SD2000 which is still revered today as one of the best, and it found a huge amount of gold for those first users. All the follow on models, as far as I am aware, are refinements of this first detector. This success was built on in terms of strong advertising (why not?) and over the years 10's of thousands of Minelab's PI gold detectors have been sold. That has resulted in what you state i.e. "If you go to any of the forums/websites where photos, videos and narratives of gold finds are posted, you will see what make and model predominates". This is advertising building on advertising and it sells detectors; that is what business is all about. There is also a psychological aspect; If everyone and his dog is using a Minelab and finds gold, then they must be good, and I will be at a disadvantage if I don't have one too.

This does not mean, however, that other detectors are necessarily inferior in detection ability. It all depends on what you want from a detector and whether there is a chance of recouping your considerable cost investment in the case of a Minelab.
Although your post was not Vallon specific, it was posted on a Vallon thread and I can see why. Kingswood said that he prefered the Vallon to the new Minelab model which is advertised as being particularly sensitive to very small gold. From the tests I have done, and others like Kingswood are doing, it appears that it does have competitive ability in gold detection in severely mineralised areas. It is also extremely rugged, as one would expect from military hardware, easy to use and a fraction of the price, although a new one would be up there, and probably above, the top Minelabs. One disadavantage of the Vallon at the moment is that the only coil is the truncated 12 x 7in elliptical, unless you want to shell out $1000 or so for a new 12in round.

I have made a few coils of my own for the Vallon and am presently testing a 6in elliptical. This has improved the sensitivity slightly so that I can now detect a 0.2gm nugget at 1.5in and a 0.3gm nugget at 3in. This is the same both in 'normal mode' and in 'mineralised mode' through a lump of Victorian ironstone. A US nickel comes in a 13in on this coil and I am happy with all these figures and would say that they are more than adequate for what I would want to do. I would also look for ground that has not been hunted to death so that only fly spot flakes remain. I know I would not have the patience to go loaming electronically.

Eric.

[kingswood]

The days of easy pickings for the average person hunting for gold on known ground are gone. Many potential buyers are in reality, inveterate gamblers. After putting in much time on research for likely locations, and expending considerable fuel and precious free time to get to the chosen spot, they are not going to further stack the already high odds against - by use of a product with inferior detection ability.
It seems a certain manufacturer cottoned onto this. If you go to any of the forums/websites where photos, videos and narratives of gold finds are posted, you will see what make and model predominates. And more importantly, what size of gold is predominately found.

Loaming is a well known method for zeroing in on the source. Being able to see and count the specks in the pan indicates whether its time to move to new ground, or keep looking. Same with gold detecting, its a form of electronic loaming. Those small, or weak and faint targets are the breadcrumbs that lead to the heart-pounding "big-uns".

Yes I agree with this....But recently a 5kg nugget was found not far from here and ounce+ nuggets are found here all the time...its just not "advertised' much

[greylourie]

Not Vallon related. But here is my take.

The days of easy pickings for the average person hunting for gold on known ground are gone. Many potential buyers are in reality, inveterate gamblers. After putting in much time on research for likely locations, and expending considerable fuel and precious free time to get to the chosen spot, they are not going to further stack the already high odds against - by use of a product with inferior detection ability.
It seems a certain manufacturer cottoned onto this. If you go to any of the forums/websites where photos, videos and narratives of gold finds are posted, you will see what make and model predominates. And more importantly, what size of gold is predominately found.

Loaming is a well known method for zeroing in on the source. Being able to see and count the specks in the pan indicates whether its time to move to new ground, or keep looking. Same with gold detecting, its a form of electronic loaming. Those small, or weak and faint targets are the breadcrumbs that lead to the heart-pounding "big-uns".

[kingswood]

Just a bit of info for comparison
Spent a few hours this morning with the wife's Minelab sdc2300. Now comparing this to the Vallon, the Vallon is by far the better designed machine. The 23 batteries have a habit of disconnecting every time the coil hits a rock and then the machine goes thru a re-start. I also lost count of the times today that I put the 23 on the ground to dig a noise and the thing turned off and back on!!
I have dropped my Vallon when I tripped over a log and the thing still went on working away!! Google reveals that it is a known issue with the 23 and recommendations are to use some tape around the batteries...you'd think that for $3700 AUD, they would have solved that issue before release really !!
The 23 is dynamite on small things though!...picked up a tiny piece of lead fragment that I struggled to see even once it was in the scoop.
Yesterday, while swinging the Vallon, detected a tiny piece of wire that was less than 3mm long.
I guess the question is; Do I really mind if the Vallon misses 0.2g flakes of gold??....probably not really. I'd rather have something decent !!
The wife can have the 23, I will stick with my Vallon

[Ferric Toes]

Hi Eric, thanks for the info on the 5" coil, I'm interested in your results
So the circuitry is happy if you just trim the coil resistance with resistors ?
did you use the 7x.2 stranded wire for the 5 inch ?
Thanks

Yes, the circuitry seems quite happy to have the resistance trimmed this way. I use the same method on the ferrite cored probes that I made, where the winding resistance is quite low. You can of course use thinner wire but trimming this way is easy. There is ample room inside the Souriau connector to house the resistor as it is best not to have it at the coil end as the metal terminations are detectable.

I have gone back to using enamelled single core 0.53mm wire as it makes for a smaller bundle. I only used the Teflon 7/0.2 wire in the 15in coil where the shell had sufficient depth to accomodate it. I found out that the Teflon wire was silver plated rather than tinned which is just as well as the resistance with cable measured 4.6 ohms, which is still OK. The Whites 12in shell is quite shallow, so the 0.53 wire was used there. Provided the spiral wrap is used to space out the shielding material, the resonant frequency remains sufficiently high. The enamelled single core is also much cheaper than Teflon stranded, so that is a consideration.

Eric.

[6666]

Hi Eric, thanks for the info on the 5" coil, I'm interested in your results
So the circuitry is happy if you just trim the coil resistance with resistors ?
did you use the 7x.2 stranded wire for the 5 inch ?
Thanks

[Ferric Toes]

My first small elliptical coil did not work properly when I tried it on the field at the back of an old mill. Any bit of vegetation the coil touched caused the detector to sound off, which is the symptom of a disconnected shield. The only reason I can think of is that the potting resin exothermed badly and the heat and mechanical stress must have pulled away the ground wire from the copper braid tape. The resin was a twin pack with resin and hardener automatically in the correct proportions, but it started to get warm as soon as I commenced mixing. After two or three minuted the coil housing was too hot to touch and it is a wonder that it didn't distort the shell. I had used a similar resin pack, bought at the same time, a few days earlier when I potted the 15in coil and this took 12 hours to set. I have potted hundreds of coils and not had this problem before. Maybe that pack had the wrong hardener.

Anyway, I have made a new coil using the bottom half of the elliptical former. No lugs of course so I bolted one of mine on with stainless steel screws, nuts and lock washers which give absolutely no signal. No potting as yet until I have waved it over the grass, just to be sure everything is OK. L is 1.49mH, R total is 3.8ohms, of which 1 ohm is a 3W metal film resistor inside the cable connector. Resonant frequency 160kHz. Notice how the shell becomes transparent when viewed from the underside.

Eric.

[kingswood]

Ha ha thanks.
Smashed it with a big sledge hammer into multiple smaller fragments. It is now a really weathered piece of schist with yellow spots in it...Not gold though ...
Google shows it is perhaps mica...Not 100% sure. The inside of the rock once smashed looks similar to ironstone or basalt. The outside had turned to a reddish rush colour.
Whatever it is, its not gold...But the good news is it is certainly volcanic in origin, which means my block is roughly in the right place We have an abundance of stained quarts, ironstone and shale.
The other good news is that we are picking up a fair bit of lead...means that whoever has detected here in the past has missed stuff...Hopefully they missed some gold too

[greylourie]

2 hours out today....Standard coil. Small bit of scrunched up aluminium foil easily detected in the soil at about 3 inches....Took me a while to locate it once it was out of the hole as it made such a small squeak noise! Signal was better when it was still in the ground.
Small boot tack among ironstone and laterite that signal very well from about 2 inches.
I had a great signal from a flattish looking rock...smacked it into 3 bits with the pick...1 piece of the 3 was still sounding off on the Vallon and also the wife's new Minelab SDC2300....Have it at home and I will smash it into small bits soon!...Hopefully a nugget lies inside

Fingers crossed.

[kingswood]

2 hours out today....Standard coil. Small bit of scrunched up aluminium foil easily detected in the soil at about 3 inches....Took me a while to locate it once it was out of the hole as it made such a small squeak noise! Signal was better when it was still in the ground.
Small boot tack among ironstone and laterite that signal very well from about 2 inches.
I had a great signal from a flattish looking rock...smacked it into 3 bits with the pick...1 piece of the 3 was still sounding off on the Vallon and also the wife's new Minelab SDC2300....Have it at home and I will smash it into small bits soon!...Hopefully a nugget lies inside

[Chet]

Hi Chet,
The electronics box as in the picture with the two Li-ion cells, plus back lid and belt clip weighs 0.8kg (1.75 lbs). The 15in coil, shaft, and cable weigh 1.02kg (2.25 lbs), as does the 12in coil and shaft.

The 5.5in coil and shaft is heavier because I used a standard polyurethane resin without a lightweight resin for 1st pot as per the first two. Also the top shaft is heavier as it has a flange for mounting a control box. This coil and shaft setup weighs in total 1.13kg. (2.5lbs)

For comparison, a complete VMH3CS, with 3 x D batteries weighs 2.6kg. (5.75 lbs).

Eric.

Hi Eric


That is a great savings (1.02kg, 2.25 lbs vs. 2.6kg, 5.75 lbs) in swing weight!


Thank you,
Chet

[Ferric Toes]

..being a full time dad can be interesting at times! Also noted is the leadwork..not often seen but should be mandatory with decking near or above damp course, good job there.
I have sent you a PM regarding arm supports if you have any available, Im not sure what or how you get a notification of message so have mentioned this here.
Looking forward to more nuggets of information and knowledge..and hopefully a wee little manual of hidden info on these machines.

Having had 6 children, I know all about the full time dad syndrome. They have all flown the nest and now have their own families, so home life is peaceful once again.

The picture is a bit deceiving as the damp course in the wall is about 10ft below, as I am not on the ground floor. The leadwork is to prevent the runoff water in the small grooves discharging down the wall. Underneath the deck is a concrete platform with a drainage gutter which then conducts the water into a down pipe. There are gaps between the deck planks for when we get serious rainstorms.

The other items will be dealt with in a PM during the next couple of days.

Eric.

[Ferric Toes]

Hi Eric

All around great work! Could you tell me the weight of the electronics box and the 15” coil and shaft?

Thank you,
Chet

Hi Chet,
The electronics box as in the picture with the two Li-ion cells, plus back lid and belt clip weighs 0.8kg (1.75 lbs). The 15in coil, shaft, and cable weigh 1.02kg (2.25 lbs), as does the 12in coil and shaft.

The 5.5in coil and shaft is heavier because I used a standard polyurethane resin without a lightweight resin for 1st pot as per the first two. Also the top shaft is heavier as it has a flange for mounting a control box. This coil and shaft setup weighs in total 1.13kg. (2.5lbs)

For comparison, a complete VMH3CS, with 3 x D batteries weighs 2.6kg. (5.75 lbs).

Eric.

[Chet]

Hi Eric


All around great work! Could you tell me the weight of the electronics box and the 15” coil and shaft?


Thank you,
Chet

[daverave]

I have been adding to my armoury of coils for the Vallon electronics. I now have one in a 12in shell, which I think would be my preference for beach hunting, and a 5.5in coil squashed into a small elliptical housing. These two latest coils worked first time with no problems, provided I kept the inductance, resistance and resonant freq. with certain limits. The Vallon coils I have range from 1.493mH - 1.512mH with resistances of 4 ohms and 160kHz f(res) with cable. It seems that you can go outside these limits to some degree as my 15in coil reads 1.556mH, 3.7ohms and f(res) 171kHz. That works very well.

The 12in coil was a bit closer with L = 1.493mH, R = 3.3 ohms and 160.3kHz. The 5.5in coil has L = 1.446mH, R = 2.6 ohms and 172kHz. The only worry was the low R, so I added a 1.0 ohm metal oxide resistor in series with the coil to bring it up to 3.6 ohms. Running the electronics on a bench psu set to 4.5V gave 372mA draw current for the 2.6 ohms, compared tp 332mA with the additional 1 ohm, so the resistor was cemented into the end of the coil housing. The latter level of current is similar to the standard Vallon coil at this supply voltage.

To get L close as possible to 1.5mH the 15in coil requires 39 turns; 12in coil 44 turns and 5.5in coil, 70 turns. Spiral wrap on the coil, then copper fabric tape as a shield. Nickel plated copper fabric tape is to be tried on the next coil but connecting the ground wire to it requires a different method as soldering is not possible. A thin drain wire is one possibility as the sample I have has conductive adhesive. The drain wire can be between the tape and the underlying spiral wrap.

The small coil in the elliptical housing can still detect a nickel at 13in and a 18K thin gold ring weighing 3gm at the same range. This coil I plan to use in cluttered areas, such as a field we own behind a watermill. The Mill goes back to the 13th century and a quick run with the standard Vallon gave a lot of signals quite close together.

Eric.

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Hi Eric....A very impressive line up indeed