TESORO GOLDEN SABRE

[Pompey]

hi Ivconic ive had a look &think TGSL is a great project &am going to try to build one as my first project~ i've had alook at the complete details in the projects section and just wanted to check on a couple of things before i start~

-for the capacitors they all match up with the parts list and schematic but when i looked at the placement OC theres seems to be ten 0.1 on there &only one on the schematic&parts list, also five 0.022 instead of seven on the schematic and for the RXc shown on the placement, is this just the one 0.015?

-for the resistors i havent checked with the placement OC yet but on the parts list~ R1 2k2 & R2 24K & R52 330are missing, also R4 1K & R5 330 ithink must be R56 &R55, there are 3 values for R6 im checking the first one 47K is right~ and for the amended R13 &14 values the schematic shows 4K7 but parts list has 5K1 could you let me know which to use, thanks~

Never mind part list has some mistakes -pcb is correct.Put all parts as on pcb.Schematic is also correct.

[Math]

ok but am just beginner a &bit confused by the 0.1 onthe pcb placement are these 0.1nf =100pF, thanks

[Pompey]

ok but am just beginner a &bit confused by the 0.1 onthe pcb placement are these 0.1nf =100pF, thanks

0.1 means microfarad ,so 0.1=100nf

[Math]

great thanks for help Pompey, just ordered parts now~

[simonbaker]

When disrimination pot is replaced with 10k sinus on pin1 improves.Sinus on pin1 depends from Tx sinusoide.I tried this.When you put 10k disc pot Tx signal goes weaker and it`s crack at the top disapears -sinus on pin (LF353) improves too.I think that disc. pot must be 10k -in TGS there are 100k and 10k paralel,so 10k is correct I think.

That is interesting point about parallel 10k pot on original schematic. I tend to agree.

However, the funny thing is that Molzar's original Tesoro TGS still had somewhat ugly waveform at LF353 pin 1 also, even with all the circuitry. That was surprising. http://www.geotech1.com/forums/showp...postcount=3896 (see pdf files).

But I agree 10k pot seems like it would be more consistent with original circuit. And your tests say it improves the signal so -- good observation!

I devised another circuit to get rid of the "oscillations", but I don't think it is worth trying if your oscillations are not too bad.

-SB

[Molzar]

[quote=simonbaker;106338]That is interesting point about parallel 10k pot on original schematic. I tend to agree.

However, the funny thing is that Molzar's original Tesoro TGS still had somewhat ugly waveform at LF353 pin 1 also, even with all the circuitry. That was surprising. http://www.geotech1.com/forums/showp...postcount=3896 (see pdf files).

Hi Simon,

If you are referring to Image 3 (LF353 pin 1) in the pdf, the picture (left) is Max's handmade (which has distortion) the graph (right) next to it is the original machine / coil (no distortion)

So the original has no distorition.

Molzar

[ivconic]

.

[simonbaker]

[quote=Molzar;106340]

That is interesting point about parallel 10k pot on original schematic. I tend to agree.

However, the funny thing is that Molzar's original Tesoro TGS still had somewhat ugly waveform at LF353 pin 1 also, even with all the circuitry. That was surprising. http://www.geotech1.com/forums/showp...postcount=3896 (see pdf files).

Hi Simon,

If you are referring to Image 3 (LF353 pin 1) in the pdf, the picture (left) is Max's handmade (which has distortion) the graph (right) next to it is the original machine / coil (no distortion)

So the original has no distorition.

Molzar

Thanks Molzar, I completely misunderstood your presentation. Now I understand; photos on left are Max's handbuilt, graphs on right are your original TGS.

So no distortion of discrim signal at LF353 pin 1. Makes sense now. Oscillations are because our handbuilts use larger oscillation voltage (because no feedback JFet), and it causes overdriving of LF353, which makes oscillations. Original TGS has smaller TX voltage (10 v pp).

Apparently 10k pot instead of 100k pot helps some in our circuit also, good to know.

-SB

[Stefano]

The same for me. I thought that the images to take as good were the ones on the left!
Just now I realize we had the orignal TGS scope pictures sampled on a standard Tesoro setup (Tesoro coil and circuit). Very good.
But if these are the waveforms which we I can consider as reference, I can't understand why the pictures F1 and F2 show as phase difference of -20 and -30 where I expected to be +20.

[Dennis the Mennis]

[quote=Molzar;106340]

That is interesting point about parallel 10k pot on original schematic. I tend to agree.

However, the funny thing is that Molzar's original Tesoro TGS still had somewhat ugly waveform at LF353 pin 1 also, even with all the circuitry. That was surprising. http://www.geotech1.com/forums/showp...postcount=3896 (see pdf files).

Hi Simon,

If you are referring to Image 3 (LF353 pin 1) in the pdf, the picture (left) is Max's handmade (which has distortion) the graph (right) next to it is the original machine / coil (no distortion)

So the original has no distorition.

Molzar

Same for me ....

Does anybody know if Max's machine did work with these scoop tracings ?

regards

Dennis the Mennis

[simonbaker]

[quote=Dennis the Mennis;106483]

Same for me ....

Does anybody know if Max's machine did work with these scoop tracings ?

regards

Dennis the Mennis

I believe Max's machine worked fine. Apparently the oscillations in the discrim signal do not matter that much (surprise). However, if they are extreme, you will probably have trouble with the discrim control. In theory, those oscillations also lose a little gain from the detector. But very good TGSL machines are made even with some oscillations as far as I can tell.

The difference in null phase is curious also. However, as mentioned elsewhere, I feel the null phase is not as critical as others think, so long as the detector (Jfet) output bias does not go too negative and forward bias the JFet. Also, the original TGS may not perform as well as the home-builts, so maybe Max, Ivconic, and others have actually improved the design.

-SB

[Molzar]

Are you using DD or concentic coils?

I think you have to take into account that the original 8" coil for TGS is concentric design, not DD. I think this is why (maybe?) shift is in other direction.
Other characteristic (Ampliture near metal or iron, direction of movement (left or right) of Rx signal when near metals.) are also reversed comparing concentric to DD.

Also not sure what coils Max was using during his test, DD I presumed, but I know he also had a Spider coil (concentric).

Also has been my experience that more Tx voltage (amplitude) creates more distortion, probably for the reasons stated in previuos posts.

Molzar

[Dennis the Mennis]

Are you using DD or concentic coils?

I think you have to take into account that the original 8" coil for TGS is concentric design, not DD. I think this is why (maybe?) shift is in other direction.
Other characteristic (Ampliture near metal or iron, direction of movement (left or right) of Rx signal when near metals.) are also reversed comparing concentric to DD.

Also not sure what coils Max was using during his test, DD I presumed, but I know he also had a Spider coil (concentric).

Also has been my experience that more Tx voltage (amplitude) creates more distortion, probably for the reasons stated in previuos posts.

Molzar

If you are refering to me :
I'm using a DD , at least I'm trying to make it work with a DD coil , I don't know what Stefano is using if you were refering to him ( I thought he had a 8' Laser coil but I don't know what type it is )

regards

Dennis the Mennis

[ivconic]

Are you using DD or concentic coils?

I think you have to take into account that the original 8" coil for TGS is concentric design, not DD. I think this is why (maybe?) shift is in other direction.
Other characteristic (Ampliture near metal or iron, direction of movement (left or right) of Rx signal when near metals.) are also reversed comparing concentric to DD.

Also not sure what coils Max was using during his test, DD I presumed, but I know he also had a Spider coil (concentric).

Also has been my experience that more Tx voltage (amplitude) creates more distortion, probably for the reasons stated in previuos posts.

Molzar

That is interesting observation. And i think you could be on right track.
Maybe i am wrong, but i think Qiaozhi already posted somewhere something about differences between DD and CC coil setups (reffering phase shifts etc..)

[Stefano]

http://www.geotech1.com/forums/showp...8&postcount=20