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Originally posted by CDI View Post[ATTACH]36792[/ATTACH]Hi Ivica, thx for posting those nice project's, but can u please mark these values?
I will complete that and post it again.
That draw i did only as reminder, for servicing purposes.
Though is easy to distinguish those, just follow the schematics i posted.
Everything is the same, it is the very same detector.
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Originally posted by CDI View Post[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:Attached Files
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Originally posted by ivconic View Post
I had this one also, completely forgot about it!
It is more completed:
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.
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Originally posted by CDI View PostThaaaank'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.
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.
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Originally posted by ivconic View PostI 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.
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)
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Originally posted by CDI View PostLast 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.
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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...
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Originally posted by CDI View PostYes, 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...
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.
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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.
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