My TGSL Build

Now I'm in the quandary of buying or making a coil.. I don't know which coil is the right one to buy, and I don't know which housing is the correct one to buy if I do build my own. Time to cruise the forum for the answer! 

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http://www.thunting.com/smf/index.php/topic,27269.msg193511.html#msg193511

Hahaha, yeah.. It's a one off deal for me. I plan to get a cheapo stick at Radioshack or ebay, along with some 100K pots to put on the outside for ground. Keep in mind I'm using lead free solder with a flux core. Made the job much easier. I got the stuff at radioshack.

In a month I'll be able to afford the coil housing, etc in sound mind. I redid my soldering points after that picture because there were some dry points. now it's all dandy. I'm not too concerned with 100% hole coverage, as long as there is suffucuent contact with the lead, the juices will flow. I plan to put some adhesive foam in the casing as shock mounts, so that's even less to worry about and parts getting jarred out of place, though that's impossible at this point. I have been thinking of casting the finished board with leads from the pots and coil in some clear epoxy resin to make it water proof. I don't know if that's a great idea or not. Just throwing that idea out there.

Posted on: September 04, 2011, 05:14:58 AM

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Here's a cool forum with useful info.

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Talks about conformal coating, which you can buy in a spray can! I probably won't do this, but it's an interesting subject.

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http://www.thunting.com/smf/index.php/topic,27269.msg193522.html#msg193522

Hi guys and gals,

I built and heavily modded IGSL and now I'm almost happy about the way it works. There is one detail about the Fe channel that isn't put right, and I fixed it ikebana style. The rest of it is fine, but the gain stages may be improved a bit. More about my mods later 

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http://www.thunting.com/smf/index.php/topic,27269.msg229365.html#msg229365

It is not polite to drag stuff from other forums, so I'll just make a list of it all. When I do the final touches I'll make a video (if my camera and youtube like each other) fix a schematic with all changes and give final notes. Changes I made are:
- LM833 is turned into a true differential amplifier - this allows for unshielded center tapped Rx coil
- GEB channels are ported to a single GEB channel control
- pins 8&9 of U4 and 10&11 of U7 are swapped, thus fixing the Fe channel
- gain stages are scrambled a bit - second stages feedback capacitors are removed, first gain stages' diodes are put in place of removed capacitors antiparallel to the existing ones in the second stages
- Disc Sens is now a single pot - thanks to fixing the Fe channel error
- Threshold control is actually audio volume control, and it got its stereo potentiometer
- circuitry around U7 is reworked and many components are removed, anti-chatter is now on C20 and C33 only
- C19 and C34 are reduced to 22n, causing considerably less delay.

I am still playing with audio stages, but so far this is working nice. I already found some tinsmith thrash in my backyard, pieces of iron, a jar lid at over 20cm depth... and gave up. Today i fixed my shaft, and after only a bit of tinkering with audio I'm off for real treasure hunting.

I'm mostly active at Geotech forum, and you'll find me there by handle "Davor"

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http://www.thunting.com/smf/index.php/topic,27269.msg229369.html#msg229369

Well, I waited a long time with the thing almost completely soldered up and Starting Yesterday I started thinking about buying a coil for it again. I think I'm going to forgo the coil production. So I hope to be adding more pics as the project progresses.

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http://www.thunting.com/smf/index.php/topic,27269.msg233416.html#msg233416