Vallon VMH3CS Mine Detector

[kingswood]

Well almost the full kit, as I have a few other ideas to investigate.
All I need now is an unthrashed area with lots of buried treasure. Nuggets, rings, coins or Spanish gold will do.

Eric.

[ATTACH]39793[/ATTACH]

Excellent work Eric!
Looking forward to seeing photos of all your good finds

[Ferric Toes]

AA batteries for Vallon power

One problem that has been raised in this thread, is that the balance of the VMH3CS is a bit coil light due to the heavy D batteries which weigh about 140gm each. Today I received some AA to D battery converters in which you can put 1-3 AA cells. I have some rechargeable ones with a capacity of 2300mAh so 2 cells in each converter give 4600mAh. Each of these pseudo D cells weighs 75gm so there will be considerably less weight on the back end of the detector to bring the coil down. It should run the detector for about 15 hours so no problems there.

I have a scrap Vallon battery tube, so I loaded three pseudo D's into that and charged them all up together. Everthing worked fine and the detector felt much better balanced. As you have seen from my recent posts, I have a range of coil sizes, all of different weights, so now I have more options to get the best balance. Put another cell in each converter, or leave one out, plus adjusting the length of the telescopic shaft.

The converters I bought appear to be rugged and the AA batteries fitted snuggly. In fact they need not be removed from the 3 converters as the whole lot is charged together. In old money, the detector is about 0.5lbs lighter with the 2 cell arrangement.

Eric.

[Mdtoday]

One problem that has been raised in this thread, is that the balance of the VMH3CS is a bit coil light due to the heavy D batteries which weigh about 140gm each. Today I received some AA to D battery converters in which you can put 1-3 AA cells. I have some rechargeable ones with a capacity of 2300mAh so 2 cells in each converter give 4600mAh. Each of these pseudo D cells weighs 75gm so there will be considerably less weight on the back end of the detector to bring the coil down. It should run the detector for about 15 hours so no problems there.

I have a scrap Vallon battery tube, so I loaded three pseudo D's into that and charged them all up together. Everthing worked fine and the detector felt much better balanced. As you have seen from my recent posts, I have a range of coil sizes, all of different weights, so now I have more options to get the best balance. Put another cell in each converter, or leave one out, plus adjusting the length of the telescopic shaft.

The converters I bought appear to be rugged and the AA batteries fitted snuggly. In fact they need not be removed from the 3 converters as the whole lot is charged together. In old money, the detector is about 0.5lbs lighter with the 2 cell arrangement.

Eric.

That's a good idea, more options, better balance, less weight, has to be a win!

Brian

[nelson]

An AA to D battery converters , works excellent on my valon too. It rest lots of weight

[kingswood]

Fun day out with the Vallon.
Picked up a 0.5g round shot gun pellet easily..maybe an inch under the surface.
Many (and I mean many!!) bits of wire, lead and metal scrap....worked an old mine area that had heaps of trash
I was surprised to find a bit of aluminium foil that I think was the outside wrapper from aspirin...It made a slight signal and I found it at about 2 inches...Lucky it was scrunched up as when I unscrunched it, the coil would not even detect it!
I am actually enjoying swinging this detector...It "feels" right to me...Much more comfortable than the others I have used. The GB is awesome. I have not had an issue in a long time with the standard coil.
Now I just need a bit of gold to prove to myself that it's all been worth the effort!

[Ferric Toes]

The real use of a Vallon

In today's (3rd June) Daily Mail is an article entitled 'Bomb Proof' by an army staff sergeant. The article and accompanying picture, which includes a Vallon VMH3CS, shows clearly the horrendous situations in which these mine detectors were used.

Many of the used ones that we have now, that are being turned into treasure detectors, must have witnessed some terrible scenes. How many lives were saved; how many lost. Food for thought.

Eric.

[6666]

Thanks Eric, just googled it, if you are quick you can read it online
http://www.dailymail.co.uk/news/arti...minefield.html

[Ferric Toes]

Fun day out with the Vallon.
Picked up a 0.5g round shot gun pellet easily..maybe an inch under the surface.
Many (and I mean many!!) bits of wire, lead and metal scrap....worked an old mine area that had heaps of trash
I was surprised to find a bit of aluminium foil that I think was the outside wrapper from aspirin...It made a slight signal and I found it at about 2 inches...Lucky it was scrunched up as when I unscrunched it, the coil would not even detect it!
I am actually enjoying swinging this detector...It "feels" right to me...Much more comfortable than the others I have used. The GB is awesome. I have not had an issue in a long time with the standard coil.
Now I just need a bit of gold to prove to myself that it's all been worth the effort!

I'm pleased that the GB is awesome. That was the one thing that I thought the Vallon might fail on, as all the official tests I read were on soils that are considerably weaker in ferric mineralisation than those in Australia.

I have being doing a bit of further refinement on the Vallon but have not had time to go out and do any real hunting. I have tidied up the audio jack that I re-routed to the rear end and added a 'speaker' that is louder than the internal one. This can be plugged in instead of phones. There was just enough room for the step down transformer inside the main box. The speaker is an old moving armature telephone insert of 150 ohms impedance and mounted the way shown gives better air loading on the diaphragm. It could be mounted on pillars straight off the Vallon case, but I did not want to drill into that as the speaker feature is still experimental.

Eric.

[kingswood]

Good work Eric
I am toying with the idea of trying some type of signal booster so that I can alter the tone.....something with a treble/bass/gain adjustment. I wonder if a mini 9v battery powered guitar booster effect pedal would work??...
There are signal boosters for minelab and these could possibly be made to work too...

[Mdtoday]

Nice work Eric!

I just noticed in the photo, the arm rest top section screws on, the one I have is a single piece.

Brian

[Mdtoday]

Getting closer to the yellow stuff Kingswood

[Carolina]

This is the newer two piece arm rest. $100.00+ and any tariffs. An additional $10.00 will get you the arm strap.

[Mdtoday]

This is the newer two piece arm rest. $100.00+ and any tariffs. An additional $10.00 will get you the arm strap.

Thanks for the info Carolina, wow a little on the expensive side after US to AUS$ conversion but interesting all the same
I will probably machine and fit a Garret or similar piece to fit later as Eric has done.

Brian

[kingswood]

Getting closer to the yellow stuff Kingswood

Its here somewhere...Just need to locate it
Had an interesting 2 hours this morning. Went to a spot I have not been to previously...a down sloping hill littered with broken quartz and banded ironstone. GB was spot on and easy...but I spent most my time digging up hot rocks. Need Eric to design a DD coil for me
On a very positive note, I ended up directly under overhead electrical wires and no issue with EMI at all.
Got the biggest signal I have had so far...then noticed the Water Dept's locator sign indicating where the underground water pipe is ha ha

[Ferric Toes]

Good work Eric
I am toying with the idea of trying some type of signal booster so that I can alter the tone.....something with a treble/bass/gain adjustment. I wonder if a mini 9v battery powered guitar booster effect pedal would work??...
There are signal boosters for minelab and these could possibly be made to work too...

I will have a look at the audio waveform on a scope and see what can be done. I was thinking that a simple divide by two circuit might help to bring the frequency range down; then filter the sharp edges off to make it more pleasant to listen to.

I had a SD2200 and you certainly need a booster for that. I used a small Koss device that you could alter the high, medium and low tones plus having some amplification. It was an EQ something, but I no longer have it as I sold it with the detector some years back. You don't need boost with the Vallon but you do need the transform the high impedance for piezo devices down to something lower for standard phones.

Eric.