TESORO GOLDEN SABRE

[dfbowers]

My TSGL

TGSL

[dfbowers]

Simon,

Yep, I'm using the LM7808. As you can see, it regulates down to 7.9V with a 12V source. The only difference in my circuit is that I am using one TL081 and one TL061 in place of the LM308s.. I need to order a pair of TL071s or TL081s I guess. I'm using cheap ceramic caps throughout except for polyester caps for the TX and RX tuning. No cable yet as I need to fill my coil shell. Otherwise, the circuit works exactly as advertised.

Oh, if you DO try to duplicate, try the AM mode as well.. on mine the performance gain is more pronounced there.

Thanks

DOn

[simonbaker]

Just curious.. I have been playing with my TGSL and just for fun, I replaced my 12V power source with an alkaline 9V battery and immediately noticed an increase in performance. I gained a significant (an inch or two) increase in depth, and the audio became slightly weaker, but longer and more drawn out. The thing that caught my attention was the increase in detection depth. Anyone have a 9V battery that they could drop in theirs to see if they experience the same?

Here are some other observations:

Supply Voltage: 11.4 v (8 AA) ------------- 8.5v(9v alkaline)

Regulator output: 7.9v ---------------------- 7.1v

Negative rail: -6.1v ------------------------- -5.3

TX amplitude 15.5v p-p ---------------------- 15.1v p-p

Current consumption 24mA ------------------- 25mA

TX Frequency No significant change noticed.

Phasing No noticable difference.

Thanks..
Don

Ok, now you've got our attention...

Are you using an LM7808 regulator in your circuit or something else, or none at all?

-SB

[dfbowers]

TGSL input voltage vs. performance.

Just curious.. I have been playing with my TGSL and just for fun, I replaced my 12V power source with an alkaline 9V battery and immediately noticed an increase in performance. I gained a significant (an inch or two) increase in depth, and the audio became slightly weaker, but longer and more drawn out. The thing that caught my attention was the increase in detection depth. Anyone have a 9V battery that they could drop in theirs to see if they experience the same?

Here are some other observations:

Supply Voltage: 11.4 v (8 AA) ------------- 8.5v(9v alkaline)

Regulator output: 7.9v ---------------------- 7.1v

Negative rail: -6.1v ------------------------- -5.3

TX amplitude 15.5v p-p ---------------------- 15.1v p-p

Current consumption 24mA ------------------- 25mA

TX Frequency No significant change noticed.

Phasing No noticable difference.

Thanks..
Don

[Dennis the Mennis]

Perhaps I'm not that old ? hahahaha ;-)

[Molzar]

That's not them! These are the original guys I remember......

[Dennis the Mennis]

Dennis,

Really just pointing out that different coil designs give different results regarding waveform characteristics. This was also dicussed in earlier posts than one Stefano cited, also by Qiaozhi I think.

How is Mr. Wlison?.....

Molzar

Hi Molzar ,

Mr . Wilson sends his regards

regards

Dennis the Mennis

[Molzar]

Dennis,

Really just pointing out that different coil designs give different results regarding waveform characteristics. This was also dicussed in earlier posts than one Stefano cited, also by Qiaozhi I think.

How is Mr. Wlison?.....

Molzar

[ivconic]

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

Exactly!

[Stefano]

http://www.geotech1.com/forums/showpost.php?p=103288&postcount=20

[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..)

[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

[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

[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

[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