Magnum on steroids!

[Lubo-BG]

26Vpp coil is dd 32sm

[bernte_one]

@ Lubo
how much is tx amplitude? and what diameter is your coil?

[Lubo-BG]

Hello! I made TH version but heve some trouble. The detector work fine. Good GEB and DISC. The coil is from Wave, frequency 8kHz. balanced- 50mV on pin 1 4053. The problem is depth... about 20-25 sm for 1 euro coin in air. Treshold is nice. Where could be the problem?

[bernte_one]

big thanks ivica

[mst]

the link

http://forum.jokerdedektor.com/index.php?topic=10.0

[mst]

ulra gold vlf new desing (mst)

https://youtu.be/hKt0db2apKc

[CDI]

Must try today with Deus, i have the Lite version, but effect will be almost the same.
Im sorry for offing thread.
About the GM1, is those machine have fully 2 tones or we must use disc pot to find where machine starting to give low tone for fero? I mean like Idx Pro.

[ivconic]

Yes, i noticed that analog meter and asked myself for what u need that, lol.
This is very easy to make, take only few minutes.
Wanna ask you, what about phase? I guess there u must use scope?
Sometime i got weird problem about some type of coins, they are discriminated out, no mater if they are big.
I dont have that problem with tiny and small roman coins, but our Serbian 1 dinar or 2 are discriminated. But not all of them, only few coins. Just like they contain some procent of iron. I dont know...

Yes that's true. Some "dinars" (yellow ones mostly, but also few silver color ones too) are made from terrific alloy!
For example; XP Deus is giving fully iron audio on those, totally discriminating them.
...
No, i just did what Andy Flind suggested in his article and that's how i nulled coil from the video.

[CDI]

Yes, i noticed that analog meter and asked myself for what u need that, lol.
This is very easy to make, take only few minutes.
Wanna ask you, what about phase? I guess there u must use scope?
Sometime i got weird problem about some type of coins, they are discriminated out, no mater if they are big.
I dont have that problem with tiny and small roman coins, but our Serbian 1 dinar or 2 are discriminated. But not all of them, only few coins. Just like they contain some procent of iron. I dont know...

[ivconic]

Last time when i maked SMW 555 version, i found the 074 is better chooise if your ears can tolerate little chattering, depth increased for 20% easy, but i modified smw on that stage that we cannot call him smw more, many component's replaced, many, many hours of experimenting with more than 10 multiturn trimmers inside, various IC's and capacitors. Last thing which i wanna try is LF347 in ceramic case, as u suggested in one thread, or maybe LF147. Air test is 52-53 cm for 1 euro coin. 32cm coil size. This stole 10 years of my life.
All this is done without osciloscope, just with average multimeter.
And... TX wire 0.40, RX is 0.30 - (Musketeer version of coil, 1mh TX, 15mh RX)

For most of the job you don't need oscilloscope at all.
For setting up the coil too. Andy Flind suggested circuit from the picture bellow.
I made it and used "VU scale" taken from faulty "Seben" metal detector, you may see it on posted video demonstration, laying behind the detector.
Although i do have 2-channel digital pc scope up from recently; i founded much easier and straightforward to set up the coil with Andy Flind's circuit.
10 times easier and simpler than with scope.

[CDI]

I know what are you saying; but "rule of thumb" does not apply generally in all possible cases.
All depends on how the signal is amplified and filtered.
On some designs LM324 is better choice, on some designs TL074 is irreplaceable etc.
What's the use of high amplification if the signal is just above treshold level and dc offset is bad?
High amplification will only additionally introduce worse S/N ratio.
Especially at wideband frontends.
So there is no general rule, all depends from case to case.
However... i haven't even bother to try LF347 on this machine, somehow i missed that.
Maybe in future when i have enough spare time; i will.
In meantime if you decide to make it and if you test it; please inform us here.

Last time when i maked SMW 555 version, i found the 074 is better chooise if your ears can tolerate little chattering, depth increased for 20% easy, but i modified smw on that stage that we cannot call him smw more, many component's replaced, many, many hours of experimenting with more than 10 multiturn trimmers inside, various IC's and capacitors. Last thing which i wanna try is LF347 in ceramic case, as u suggested in one thread, or maybe LF147. Air test is 52-53 cm for 1 euro coin. 32cm coil size. This stole 10 years of my life.
All this is done without osciloscope, just with average multimeter.
And... TX wire 0.40, RX is 0.30 - (Musketeer version of coil, 1mh TX, 15mh RX)

[ivconic]

Thaaaank's...
Btw, im not fan of LM324 and TL074, according to SMW with those IC's, device is a bit jitter or loose depth, LF347 wil be maybe best chooise, but i don't wanna judge before construct my own and test.

I know what are you saying; but "rule of thumb" does not apply generally in all possible cases.
All depends on how the signal is amplified and filtered.
On some designs LM324 is better choice, on some designs TL074 is irreplaceable etc.
What's the use of high amplification if the signal is just above treshold level and dc offset is bad?
High amplification will only additionally introduce worse S/N ratio.
Especially at wideband frontends.
So there is no general rule, all depends from case to case.
However... i haven't even bother to try LF347 on this machine, somehow i missed that.
Maybe in future when i have enough spare time; i will.
In meantime if you decide to make it and if you test it; please inform us here.

[CDI]

I had this one also, completely forgot about it!
It is more completed:

Thaaaank's...
Btw, im not fan of LM324 and TL074, according to SMW with those IC's, device is a bit jitter or loose depth, LF347 wil be maybe best chooise, but i don't wanna judge before construct my own and test.

[ivconic]

Several schematics on the same subject...

[ivconic]

[ATTACH]36792[/ATTACH]Hi Ivica, thx for posting those nice project's, but can u please mark these values?

I had this one also, completely forgot about it!
It is more completed: