TESORO GOLDEN SABRE

[Max]

Hi,
Max.
I will use this method.
But the interesting think is that when I null now and conect again I dont have good performance,but when I separate the windings the md give good sound??
Why?
The null should be the best point,and this is almost 1 cm away?!?!?
I havent time today to buy 3240,but tomorrow will for shore!
Thanks

Hi,
the null is the most sensitive point ? Well, this is an old problem.
For me the null point is one of the most sensitive and the safest for your detector operations, cause you stay away from saturations with op. amps.
though...
as Ivconic stated some time ago... seems that sometimes a little imbalance gives better performances. That's true... expecially for air tests.

You know... if you can put your detector on "the edge" just before of saturation occours you'll notice a slight better detection.

That's why there is always an inertia due to many factors (capacitive effects, preamp. etc) so if you avoid that just avoiding instability, you'll get the best air-test for that coil.

That's surely true for air tests, I know cause also me sometimes don't nulled for minimum voltage (e.g. 1mV peak to peak) but some few mVolts.

But then I had problems with a coil unbalanced that way in the field test, so decided making other coils nulling at best. That's cause "ground" signal could easy put your op. amps. in saturation if you haven't a near-to perfect null.

Best regards,
Max

[tiktak]

Hi

Hi,
Ok!
Thanks
But its very poor performance when nuled!
I have average multimeter and its lowest ACV range is 0-200 and I adjust just between 0 and 1.

[tiktak]

Hi

I still can make this nulled this way but wondering if I haven't performance I dont'need this coil!Maybe little resistance is the reason for this?
18,8 ohms for both same!

[Max]

I still can make this nulled this way but wondering if I haven't performance I dont'need this coil!Maybe little resistance is the reason for this?
18,8 ohms for both same!

Resistance is ok. Find again a good null.

[tiktak]

hi

ok

[tiktak]

hi

I will do as you say,but when were null there were no sound at all!
Or my null was not accurate?

[Max]

I will do as you say,but when were null there were no sound at all!
Or my null was not accurate?

Hi,

Can't you restore original performace ?

I think so that :
- null could be inaccurate
- or you have bad connections, a mistake.


Kind regards,
Max

[tiktak]

Hi,

Hi,
Max.
I test again and when nulled no sound afther reconect as it should be!!
So not the right null!@!?!?!'
Never mind I smash the damn thing!
Now I have to wate untill 24-27 to get wire!
But I now what to do to get good homemade coil THANKS to you!
But now was very easy nulling I just leave it to swing between 0 and 1 right?
Which is the best value?
Next time I will make 26cm coil that IVCONIC show here.
And will not forget to test with 3240.
See you soon

[ivconic]

Very,very long post!


"..Ivconic can you tell us is the depth 38 cm in air with 28DD coil for dime?/what
you understand buy 1cm coin?/!"
Ehm, it's ONE SERBIAN DINAR , approx.1cm diammeter nickel coin. Since i already
used it so many times to check depth on almost all detectors,i ever saw in my life,
i just "established" it as standard coin with standard size, also standard alloy.
Why standard? I just had to have some reference according to which i can easilly
compare detectors. I could use any other coin,size,alloy...couldnt i? It is not
important at all. It is just my internal reference according to which i do a lot of
tests and checks, according to which i made several comparsions, which, on the other
hand, helps me a lot when dealing with some new,unknown design,project or original
detector...call it anyway you want. These comparsions gives me full right and
support to come here and freely claim some claims,like;
-TGS goes much deeper than Fisher 1266,
-TGS is superior over White's CL3,
-TGS goes deeper than Musketeer,
etc.etc.etc.
You can not judge about one detector,if you havent seen and tested other! Can you?
More detectors you tested,more experiences you have.More experiences you have -
easier for you to know what is good and what is not.
If photo of detectors collection Carl posted here is his own collection,than he must
be very happy and experienced man on this subject!?
Of course, meaning that he previously tested all of those and made comparsions charts?
Back to coin; why coin? Simply, one standard coin is the very best reference we can
use here. By the same coin i can test my detector here in Serbia, same as you can in
Guatemalla or New Zeland...
Other test reports doesnt mean rule. For example if i say here:
" I detected 20 roman coins at 20cm depth on old roman location..."
This should mean nothing to you! What coins? What size? Alloy? What soil?Compounds?
Mineralization? Day,night? Moisture? Propagations?
Too many decisive factors can
cause HUGE DEPTH DIFFERENCES between my handmade detector here, and your very same
handmade detector, there in Guatemalla!!!
Further,those differences can confuse you even more! You can suddenly start thinking;
"..either ivconic lie here...either something i did wrong while making my handmade..???"
How can i gain ivconics results??? What is secret? Is he liar?
Or in case my results are worse than yours;
"..is ivconic ignorant,cant achieve results i gained...???"
So to make things much simplified, we should accept as common, only reports and results
made using same method of testing. It is not possible to simulate same ground conditions
(not to mention other factors), so, although rough and unperfect, we can only relly on
detecting one single coin in the air. Same size and alloy. I was thinking; nickel coins
are so usuall....1cm size also. It is not big deal for all of us to easilly find one
nickel with 1cm diamm. and use it for comparing.
Nickel alloys are also very interesting to testing discrimination circuitry.

"Flux chaining is "proportional" to coil diameter, if you use e.g. 28cm diameter you get
some more depth."
This is very important to understand! Benefit is more depth - drawback is loss of p.pointing
and eventual instabillity (more sensitive to ground conditions).
***********************************************
I put TL071 instead LM308...same! Very stabile and good depth. TL082 instead LF353, also
very good, but lost 2-3cm...
I also put 741 instead LM308!!?? When Sensitivity is max, lot of false signals, but
when lower to 1/3 very good behavior and descent depth!
LF353 should stay unreplaced. LM308 can be replaced with TL071,TL081 or some other.
*************************************************

About audio mods:
"I am not sure it will work? Audio buffer at TGS - LM358 across that 27K is "pulling"
some voltage in range -4.xx to +3.xx volts..if i measured correctly?
On my previous mod with LM566 i had to put extra fet J107 to trigg it to -12v...it
showed as only way to make LM566 stage to work good. Direct connection gave a lot of
saturation and various "squeeking" with noise...
Either some level converter should be applied before ordinary audio amp...?
I have rough idea on my mind,only dont have it as schematic yet. It seems it only few
fets more can solve the problem. I am thinking to experiment with small capacitances
arround gate and source to make some "delay".....we will see..
CZ5...? Ehm,at the time i was very impressed with it...Now my TGS runs deeper...Yet, i
idore CZ sound!"
Actually, here at TGS, MPSA13 is working partially as "chopper" - not just as
simple amplifier. It is not so easy to apply any audio on it.
This we should reconsider more detailed.
I do not have scope here at my workshop yet, so it is so hard for me to follow signal
level and distinguish the voltage range in which MPSA stay "closed", and at what point
it is "open". Real succes would be if we make a sort of "limiter", to limit lower
point for opening MPSA13. Why? Simply, than we could adjust it better to avoid eventual
and in some cases ocassional chaters and false signals. Or apply versatile front panel
preset and adjust it from case to case...Other words, small,mum,suspectable signals we
could "reject" from audio, and allow only good,strong and clear sinals to be amplified
by MPSA13.....
That's why i started thinking other way; simply to turn to fets..only dont have clear
idea yet...
Come to think; have you ever saw Bounty Hunter Tracker 505..xx something. Cheap one..
I had chance to work with. Low depth, not serious...toy. But! Disc. was great!
In disc mode there is great audio separation. If detected item is iron - audio freq. is
noticeable lower and polyharmonic, other hand; if item is "coloured" audio freq. is
noticeable higher and sound is clear - no harmonics!?
It is also motion detector, also no pinpoint mode...
I dont have its schematics to trace and copy those disc and audio stages....
It would be very interesting to see it and try to use it to mod TGS audio...?!
Anybody have schematic? Esteban posted something about it once......
***********************************************
TikTak try this;
Connect TX coil to TGS, do not connect RX coil at all. Connect RX coil leads to
ordinary multimeter and pick 2v range AC to measure;
Turn ON TGS. Look on multimeter. You will see AC current induced in RX coil...
If hardly unbalanced, AC voltage can be higher than 4-5 volts...
Now, start balancing coils. Try to gain least voltage possible. Do that very slow!
At my 28cm coil i gained 0.015 V.... But it took me 20 minutes to adjust coils.
"Nanometer per nanometer"....Next is to use "Super Glue" and glue both coils
togather, fast and carefully not to spoil gained balance. Why super glue?
It is drying very fast.It has no relative movements while drying! Later when dry,
you can use some extra mass or glue to apply over.
And that is all! You have good nulled coil!
BTW, it is not so hard to achieve absolute 'Null'. To balance coils so good to
read 0.000 volts. There is one "region" on overlaping part where no induction
occurs at all. But i would not suggest you to finish nulling like that!
I noticed many times, on many coils, very noticeable LESS SENSITIVITY if coils
are balanced that "good".
Best sensitivity is when coils have "critical" balance...but hey! Not to much
"critical".....we dont want BFO syndrome here!
Further, my best coils so far, are balanced in manner to produce inductions
between 0.08 - 0.015 volts. Already proven on real fields under real ground
conditions...Those coils are real "coin killers" at high deths..
************************************************** *************

[tiktak]

Hi,

Thanks
Ivconic for the INFO
Will try make another coil soon.
Like yours.

[Max]

"..Ivconic can you tell us is the depth 38 cm in air with 28DD coil for dime?/what
you understand buy 1cm coin?/!"
Ehm, it's ONE SERBIAN DINAR , approx.1cm diammeter nickel coin. Since i already
used it so many times to check depth on almost all detectors,i ever saw in my life,
i just "established" it as standard coin with standard size, also standard alloy.
Why standard? I just had to have some reference according to which i can easilly
compare detectors. I could use any other coin,size,alloy...couldnt i? It is not
important at all. It is just my internal reference according to which i do a lot of
tests and checks, according to which i made several comparsions, which, on the other
hand, helps me a lot when dealing with some new,unknown design,project or original
detector...call it anyway you want. These comparsions gives me full right and
support to come here and freely claim some claims,like;
-TGS goes much deeper than Fisher 1266,
-TGS is superior over White's CL3,
-TGS goes deeper than Musketeer,
etc.etc.etc.
You can not judge about one detector,if you havent seen and tested other! Can you?
More detectors you tested,more experiences you have.More experiences you have -
easier for you to know what is good and what is not.
If photo of detectors collection Carl posted here is his own collection,than he must
be very happy and experienced man on this subject!?
Of course, meaning that he previously tested all of those and made comparsions charts?
Back to coin; why coin? Simply, one standard coin is the very best reference we can
use here. By the same coin i can test my detector here in Serbia, same as you can in
Guatemalla or New Zeland...
Other test reports doesnt mean rule. For example if i say here:
" I detected 20 roman coins at 20cm depth on old roman location..."
This should mean nothing to you! What coins? What size? Alloy? What soil?Compounds?
Mineralization? Day,night? Moisture? Propagations?
Too many decisive factors can
cause HUGE DEPTH DIFFERENCES between my handmade detector here, and your very same
handmade detector, there in Guatemalla!!!
Further,those differences can confuse you even more! You can suddenly start thinking;
"..either ivconic lie here...either something i did wrong while making my handmade..???"
How can i gain ivconics results??? What is secret? Is he liar?
Or in case my results are worse than yours;
"..is ivconic ignorant,cant achieve results i gained...???"
So to make things much simplified, we should accept as common, only reports and results
made using same method of testing. It is not possible to simulate same ground conditions
(not to mention other factors), so, although rough and unperfect, we can only relly on
detecting one single coin in the air. Same size and alloy. I was thinking; nickel coins
are so usuall....1cm size also. It is not big deal for all of us to easilly find one
nickel with 1cm diamm. and use it for comparing.
Nickel alloys are also very interesting to testing discrimination circuitry.

"Flux chaining is "proportional" to coil diameter, if you use e.g. 28cm diameter you get
some more depth."
This is very important to understand! Benefit is more depth - drawback is loss of p.pointing
and eventual instabillity (more sensitive to ground conditions).
***********************************************
I put TL071 instead LM308...same! Very stabile and good depth. TL082 instead LF353, also
very good, but lost 2-3cm...
I also put 741 instead LM308!!?? When Sensitivity is max, lot of false signals, but
when lower to 1/3 very good behavior and descent depth!
LF353 should stay unreplaced. LM308 can be replaced with TL071,TL081 or some other.
*************************************************

About audio mods:
"I am not sure it will work? Audio buffer at TGS - LM358 across that 27K is "pulling"
some voltage in range -4.xx to +3.xx volts..if i measured correctly?
On my previous mod with LM566 i had to put extra fet J107 to trigg it to -12v...it
showed as only way to make LM566 stage to work good. Direct connection gave a lot of
saturation and various "squeeking" with noise...
Either some level converter should be applied before ordinary audio amp...?
I have rough idea on my mind,only dont have it as schematic yet. It seems it only few
fets more can solve the problem. I am thinking to experiment with small capacitances
arround gate and source to make some "delay".....we will see..
CZ5...? Ehm,at the time i was very impressed with it...Now my TGS runs deeper...Yet, i
idore CZ sound!"
Actually, here at TGS, MPSA13 is working partially as "chopper" - not just as
simple amplifier. It is not so easy to apply any audio on it.
This we should reconsider more detailed.
I do not have scope here at my workshop yet, so it is so hard for me to follow signal
level and distinguish the voltage range in which MPSA stay "closed", and at what point
it is "open". Real succes would be if we make a sort of "limiter", to limit lower
point for opening MPSA13. Why? Simply, than we could adjust it better to avoid eventual
and in some cases ocassional chaters and false signals. Or apply versatile front panel
preset and adjust it from case to case...Other words, small,mum,suspectable signals we
could "reject" from audio, and allow only good,strong and clear sinals to be amplified
by MPSA13.....
That's why i started thinking other way; simply to turn to fets..only dont have clear
idea yet...
Come to think; have you ever saw Bounty Hunter Tracker 505..xx something. Cheap one..
I had chance to work with. Low depth, not serious...toy. But! Disc. was great!
In disc mode there is great audio separation. If detected item is iron - audio freq. is
noticeable lower and polyharmonic, other hand; if item is "coloured" audio freq. is
noticeable higher and sound is clear - no harmonics!?
It is also motion detector, also no pinpoint mode...
I dont have its schematics to trace and copy those disc and audio stages....
It would be very interesting to see it and try to use it to mod TGS audio...?!
Anybody have schematic? Esteban posted something about it once......
***********************************************
TikTak try this;
Connect TX coil to TGS, do not connect RX coil at all. Connect RX coil leads to
ordinary multimeter and pick 2v range AC to measure;
Turn ON TGS. Look on multimeter. You will see AC current induced in RX coil...
If hardly unbalanced, AC voltage can be higher than 4-5 volts...
Now, start balancing coils. Try to gain least voltage possible. Do that very slow!
At my 28cm coil i gained 0.015 V.... But it took me 20 minutes to adjust coils.
"Nanometer per nanometer"....Next is to use "Super Glue" and glue both coils
togather, fast and carefully not to spoil gained balance. Why super glue?
It is drying very fast.It has no relative movements while drying! Later when dry,
you can use some extra mass or glue to apply over.
And that is all! You have good nulled coil!
BTW, it is not so hard to achieve absolute 'Null'. To balance coils so good to
read 0.000 volts. There is one "region" on overlaping part where no induction
occurs at all. But i would not suggest you to finish nulling like that!
I noticed many times, on many coils, very noticeable LESS SENSITIVITY if coils
are balanced that "good".
Best sensitivity is when coils have "critical" balance...but hey! Not to much
"critical".....we dont want BFO syndrome here!
Further, my best coils so far, are balanced in manner to produce inductions
between 0.08 - 0.015 volts. Already proven on real fields under real ground
conditions...Those coils are real "coin killers" at high deths..
************************************************** *************

Hi Ivconic,
I agree that direct connection for TBA820M's input was a bad idea... have connected then after C517 and audio was loud etc but I was not satisfied.
About "delay" you mean a monostable ? I was thinking too same thing... cause the weak audio response is due, at higher depth, to fast commutation of op. amps... (too fast) to get a good sound.
I think that e.g. a 300mS monostable could be fine there... adding some inertia when saturation occours.
Of course, pinpoint would be damaged by greater inertia.

About tones... I think the way one could wire such a mod. is related to the 2 channel informations:
watching at voltages of the 2 lm308 outputs is the key to get multiple tones.
One could also use outputs of comparators near the sens pot.

When iron is present channel output voltages are in oppositions, thus giving zero effect on output. When coloured metal is present, instead, channels have similar behaviour.
That way is possible making a multitone information.

Problem is that if you vary disc pot setting you'll vary also audio response, and that's no good, confusing the user. So a real mod. must be place disc pot as trimpot with minimum setting, then leave the user just ear the sound difference to disc stuff, not moving the pot (as in original GSabre design).

Do you think is possible that way ?

Kind regards,
Max

[tiktak]

Hi

Ivconic what do you think can I use CD3240 insted of LF353?
Will this afect performance?

[tiktak]

Hi

Max,
Are you using metalbox for device and ground all to box?

[Max]

Max,
Are you using metalbox for device and ground all to box?

Hi tiktak,
at now ?
No no, have just the PCB, wires, etc on table, no case for now. Have no time for that... just some rough testing.

On bandidoII I had to make gnd planes, then find a suitable metal box... but with GSabre PCB no need of anything. You can test as you want, it's really stable.

No problems.

Kind regards,
Max

[tiktak]

Hi

Ehm, it's ONE SERBIAN DINAR , approx.1cm diammeter nickel coin.

Ivconic what is this coin 1cm?The smalest I think is 1,5cm D!
please check again!If this is true than I am not even close to the results that I have to achive!!!!
Can you preforme air test with 1 euro coin and post results please~!