Off to a good start with the EuroTek Pro, Plus minor changes to the unit.

Received the EuroTek four days ago, Perfect timing had the weekend off hit an old park and a sports field. On the last trip out dug an 18K ladies ring from the sports field, This makes two gold jewelry pieces the past week from the same field. When time allows will take her out to a couple of old sites see how the unit does in an iron ridden site, Based from my recent hunts can see a need for a smaller coil in areas with iron. It's fast but with the 11" coil and maybe the lower kHz the euro doesn't appear to get away with what the T-2 can with the 11" coil in an old site with lots of iron, Don't get me wrong the euroTek does well very well in fact but a smaller coil appears to be the better coil for a trashy area with iron.

Added on a manual GB the other day, This was the first phase of the adding on a ground balance pot and last night finished the second phase both go hand in hand.

What I wanted to do was maintain the stock preset GB yet with a flip of a switch go to manual GB, Now the unit can operate with stock preset for coin shooting and if someone new to the hobby used this as a loner can use the preset GB instead of fussing with manual GB.

Works great! I destroyed the stock minature trimmer pot by accident and as tiny as it is that was easy so had to replace it with another mini trimmer pot and remount it in a another area.. It's a simple mod basic layout going with a parallel setup.

Before I forget, One of the pics shows the short GB window when using manual GB. Like I was saying earlier this circuit is different from all the others I've encountered.

The mod has one drawback to adding on a GB and I knew this before starting the mod thanks to Pimento he mentioned the ID would be effected if adding on a GB to the euroTek, That is what I was needing to hear for because if the visual ID is effected then the manual ground balance does carry over to the disc mod.

For relic hunting this issue wouldn't matter since we dig all conductive signals above iron, Target ID is effected with the added GB. Depending how bad the dirt is or good for that matter any adjustment to the GB will effect ID. Not by much depending on soil conditions but for coin shooters one must rememeber these ID differences.

However, I adjusted the GB pot so placing the GB knob at 12'oclock will place the unit back to the same GB setting as preset GB and now with the added preset GB I can compare signals see if an added GB has it's advantages. It's cool, Hunt with manual GB or flip the switch it goes back to preset GB.

At least it's completed, A fun mod glad it turned out as planned.


Hope the pics show, And Thanks Tom for the great forum and Thanks Pimento for the information I needed to know.

Thanks for looking,
Paul (Ca)

Interesting way of doing it, I would have put the preset pot in series with the main one, and set it so fully-clockwise ( or counter-clockwise as appropriate) was neutral/stock setting. Then the switch isn't needed.
If you ever need to restore the original setting, I think adjusting for a precise target ID on a high-conductor (eg. half US dollar) should work. That is to say, if out the-box a half-dollar read as 90, then tweaking your pot or preset to give 90 will mean you are at the stock setting.

I see what mean going with the duel GB feature without the switch, that would be the better approach for a seasoned hunter.

The switch setup allows a beginner to quicky bond with the unit without having to adjust the primary
GB pot to place the unit in GB preset. A flip of a switch shifts it over, plus with this setup can compare signals without having to readjustment the primary GB pot to see if the manual GB really does help the machine maximize performance with a proper GB.

Fun unit for sure, looking forward to using it more offen.

HH, Paul(Ca)

By the way, since you've modified the machine already about where do you think the internal GB is set at?

Good question Mark,

Give me a day or so to run more test out in the field, would like to compare both preset and manual GB at various places see how much they differ.

Before adding on the second GB phase, Noticed ground conditions changed often from one park area to another. Quickly made a GB adjustment and continued swinging, that was cool seeing ground conditions change from one patch of dirt to the next and being able to make the GB adjustment as conditions changed.

I'll get back with with an answer for you were preset GB falls, give me a day I'd so.

HH, Paul (Ca)

Nice mod Paul,,,,

I am still not convinced the omega and G2 ground balance works in disc mode...

Those detectors have all metal modes and they need the ground for that and pinpointing..But believe the disc i.d. would be off on them also if it effected the disc circuit in ground balancing..

Good info

Keith



Edited 1 time(s). Last edit at 06/12/2013 07:28PM by Keith Southern.

Hi Keith,

Sorry for the slow reply, I feel you may be right on the GB not carrying over to disc mode. Just need to conduct more test to make sure, And if GB does not carry over to the disc mode that will be a relief knowing. I'd rather know for sure than be in the dark wondering

Thanks for the input my friend,
Paul (Ca).

I know on the Gold Bug's S.E. the frist batch I discovered would not hit on silver above dime...the cure for it was to send it in and they FIXED it..which anounted to adjusting the internal V.R. jsut a hair .. then the big silvr came in...yet the I.D.'s shifted slighlty...

When First Texas told what had happened it was that the assembly line techs had aligned the Gold to the same internal setting as the Greek series machine's....(Not Knowing any better)..so the higher freq required a little more travel on the V.R. to get it set right...

But the I.D.s do change when the internal ground is turned....and I am not sure how much range the ground has...I would bet its not a whole lot...just enough to align the final product for use...

I have tried and tried to manipulate the Omega and G2/Gold Bug to fasle in disc mode. by running the ground settings real low even into the salt range and no ground feedback is ever heard...So I am convinced on those models the ground bal is for pinpointing and all metal hunting.....the disc mode is locked in by the internal pot for I.D. ability...

I believe the Tesoro line does this also....And maybe the Prizm series also from white's...and SOME of the green Garrett's..

On a side not the T2/F75 does not exhibit this behavior....if you get the ground bal out on those machine's you know it right away...theres more sophisticated software working to compensate the I.D. for ground setting's...

Thats got to be why I love the T2 the best of all FT machine's...The depth is better because of the ground carry over into disc..

If I could have a T2 with variable tone break in 2 tone I would be a happy camper...Thats all the machine lack's....I can get very good depth out of a T2 in my dirt...really good depth!!!! but for iron work in a sleuthy way it could be on the same level as a GMP/DEUS/DTVG with variable tone break added oe at least in theory I think it could ...

Keith

Keith,
Couldn't you verify the ground balance works in disc mode by observing the loss of sensitivity to low conductors when the gb is adjusted down into the salt range?

Paul, I like your gb modification and thanks for the pictures. I'm assuming you are balancing in pinpoint mode.

HH
Mike



Edited 1 time(s). Last edit at 06/12/2013 08:41PM by Mike Hillis.

Hey Mike take a G2 and run the ground from zero to max and I cant see any differance on a gold ring...

I am not 100% sure the machine balances in Disc mode...

I have tried to find out but cant get no answers....if it does move I have a sneaky suspicion it does not move a whole lot...maybe below 40 it get's a new preset in disc? not sure...

I know a G2 can run on a salt beach...but alwasy wondered if it had to be ground balalnced to work or if it would workd say at a seting of 75 as long as you did not use all metal? ...

I dont have access to a salt beach...

I wish I knew with 100% accuracy ...

What does your F5 do when you manipulate the ground bal and stay in disc mode...Do you see any changes to repsonse...

I know a AT-PRO will travel alot before you get feedback in the disc from the ground.. but its not usually over 20 point's...I can get by with 60-65 if it grabs at 80 but that's pushing it.. after that it becomes unstable to hunt with...


I will say this though...

on the original Gold bug S.E. the first one's that were aligned internally like an Omega were hotter on gold than the ones that got the internal gorund bal moved to hit silver also...

Keith

Keith, my F5 will lose a lot of sensitivity to low conductors, like gold, in Disc mode when the gb is dropped down into the salt range. It is a gradual loss as the gb is adjusted downward. On the ferrous side it is much harder to get ground falsing response as the ground signal itself is used to minimize emi response. That same functionality tends to lessen ground response noise as well. But I'll see if I can create some ground noise later in the week, or least a change in the confidence meter.

HH
Mike

Thanks Mike,

Have hope for the added GB yet, Certain test point that it may carry over to disc mode.

I'll run this past you and Keith here shortly, You guys understand detectors more than I do.

Thanks again,
Paul

Mark,

I ran those test and found the preset GB compared to all-metal GB the preset falls at 2-3 o'clock on the GB knob. Depending on ground conditions the window was between 2-3 o'clock. Allot more to the positive side on a manual GB pot.

Hope this helps,
Paul

Keith or Mike,

Here are my findings when experimenting with the manual GB, You guys are more up to speed with the hobby please share your input based from these test.

Ok, Out in the field when running the ground settings low (counter-clockwise) the unit falses in disc mode constant falsing unbearable to the ear. Ok, This was long before it was even full counter-clockwise it started to false.

However, When adjusting the GB pot full (clockwise) the unit operated great only ID was much higher. Couldn't tell a difference in performance only that target ID was off allot either direction, GB Counter clockwise ID was lower, GB Clockwise target ID was higher.

Any special test you'd like to me run please let me know, Plus, If I advance the GB pot or reduce it the unit squeals. Based from these findings do you think GB in all-metal carried over to disc mode?

Please note this was done in the added GB mod setttings,

Paul (Ca)



Edited 1 time(s). Last edit at 06/13/2013 05:32PM by Old California.

Paul, I am assuming that you use the pinpoint feature to tell you the balance point of the ground and adjust until the pinpoint audio tells you that you are balanced? That the pot you are modifying is actually a ground phase pot?

For me, an air test of a small gold item or small piece of pie plate foil that reads in the low 50 range would tell me that the setting carries over if the air distance decreases at some point as you adjust counter clockwise. I doubt you would see the same affect on a silver dollar as you adjust clockwise as there are some software stops, but you might.

I'm trying to remember who has a good video of phase response on a o'scope. Chris Gholson has a good interview with his Dad in one of his prospecting videos and they cover this and you can see the phase response on the scope......I think the Tesoro tour shows some of this as well....

HH
Mike

Paul....

That pot you are messing with inside is the Disc ground bal......

It seems to behave like it should negative counter clockwise should cause constant ground chatter and squeal and positve clockwise should be quite yet depth may be sacrificed...and the i.d will be off...

the omega and G2 have the same pot inside.. yet they also have the means to manually ground bal... but its generated from another circuit....

I know on the G2 and the omega if I turn the internal pot like your doing it will effect the machine's perfromance big time like a machine that manually ground blances both modes..such as the Tejon for example...

I am sure the external pot you have added is balancing the disc of the machine...

it's the omega and the G2 that have the factory external ground bal ability that does not seem to change the disc modes Ground a whole bunch or maybe just a little if all......

Thats why i was wondering if you would see a whole lot of gain from installing the external pot....the machine when in disc mode on the omega and G2 seem to handle the mineral fine and see through it well,,,, with the factory internal pot set for normal operation...

I think FT has approached the ground bal a bit different that normal.. and it may be in the software...

in a nuts hell

Change the internal ground pot on the g2/Omega/Euro and the machine CAn get unusable in disc mode....as it should....

Change a omega or g2 factory external ground control and put it anywhere you like all the way to zero and it still runs fine in disc mode?????

They have done something UNIQUE...yet not sure what it is...

thask's for the info..

Keith

I would say that when the internal pot is set correctly, the machine would be adjusted for neutral ground, zero degrees. Balanced to ferrite. The pot will allow fine-tuning of this phase, so should be able to adjust plus and minus from zero. How much adjustment it has is anyones guess, +/- 10 degrees? For reference, 'typical' ground gives a phase lag of 5 degrees. It looks like your front-panel pot has the same value as the trimpot (am I correct?) so you probably have the ability to go beyond 5 degrees lag and thus get the ground chatter bad, or you can set it to positive angles, where the machine will be quiet, but less sensitive (less than in the stock setting).

Thanks Mike,

Use the pin-point feature to adjust ground balance, Adjust the GB until the pinpoint audio (slight increase in audio) tells me the unit is balanced.

I tired like you said with a small piece of foil, appears to have a slight decrease when fully counter clock wise. But when I increased the GB clockwise the signal increased slightly.

Thanks Mike,
Paul (Ca)

Thanks Keith and Pimento,

Maybe with adding the external GB pot, The machine may be kind of unique and have other positive effects changing tone and ID, Been playing with it on different conductive targets as well as with ferrous targets. Can reverse the audio signals once the pot is adjusted too far counter clock wise.

Still hope something good will come out of the added GB, For the time being will use manual Gb for relic hunting and switch back to the preset when coin shooting.

Thanks again,
Paul