TESORO GOLDEN SABRE

[nelson]

Same pins

Hi, has Ivconic said, you can just replace LM308 by TL081, no mods to the pcb board needed. Ivconic also said that he has never try this but in theory must work. Don´t know anything about performance jet. When i finish mine, i ll post results.
Regards
Nelson

HEllo,
If I replace LM308 whit TL081 is there need of changing the pcb or they are with the same pin configuration?Only replace?
Thanks

Hi

Hi,
Can I replace LF353 whit TL072?Will this afect the preformance?
Thanks

[kt315]

ivconic, can you connect simply resistor 1 MOhm in parallel to the diode? NOT TO THE SOURCE

!!! a source WILL BE COME UP for comparator output in case, if DC voltage on OP AMP output will be grow !!! you NOT NEED in the loading resistor you imaged!

HELLO?????????

Hello,
Can someone finaly explain how to connect the potentiometers and switches????
And their princips of operation?
Please

[Ultimate_Haze]

???????

HEllo,
If I replace LM308 whit TL081 is there need of changing the pcb or they are with the same pin configuration?Only replace?
Thanks

Hi

Hi,
Can I replace LF353 whit TL072?Will this afect the preformance?
Thanks

[Hush]

About nulling and tuning...

As you see, need explain about nulling coils. Is it posible nulling coils without
osciloskope, with unimeter which can measure voltage peaks, and without hmm... signal generator? He-he, I haven't much instruments, but have good
will. Also need some explains about tuning... maybe someone wish to tell me something more about it? Maybe Max from Mars or Ivconic or...
Wish you all the best!

[nelson]

A picture speaks more than 100 words

Hi Ivconic. What can i said, you are the master about this golden sabre project and the picture gives me a very clear idea about how to connect the coil.
Didn´t know that you can replace that 4.7 uF caps with two in series 10 uF electrolitic caps to get 5 uF cap.
Yes i think i will try TL081, this is a very common IC here.
Again my friend, i just whant to thank you for been a good man on sharing with us your knolegment and expirencies, that let us know more and more about electronics and MD.
Best regards
Nelson

Took another look at it, and...YES! KT315 is right! I traced pcb again.
Yes KT315 you are right! How i missed that!!!??? I have few different
schematics here....I payed attention on wrong one...Shhheeeeeesh!!!
Bravo KT315 and thank you!
But about loading resistor you mentioned...? I am not sure? Yes i can agree
with you, there must be loading resistor...but it is not there? And device is
working excellent!?
I corrected schematic and here is now; i really hope complete and accurate!
Porkluvr....Yes double O coil showed best results so far...but i gave up of those!
Why? I am gonna explain why; not so suitable on terrains i've been visitng lately.
There are a lot of bush arround,tree roots all over arround, high density opsticles
and OO coil is not just suitable enough to approach to every spot;under some tree or
between some stones...when coinshooting. I do that mainly...coinshooting.
So i made hard compromise and switched back to DD (double D) coils, again...
Double D shape is much more suitable for that kind of prospecting than double O.
But if you prefer leveled terrains than i suggest you to make OO coil cose a bit
greather depth than DD coil.That was my only reason to leave OO coils for now...
No i didnt say "...no gnd connection on RX..." !? Yes there is gnd connection on RX!
Must be! But not at pcb. That's why i didnt draw gnd connection in schematic.Not to
confuse somebody who might decide to draw pcb according my schematic...Later should
scratch or cut that piece of pcb to correct mistake...
GND connection at RX should be made in coil.
Pay attention on cable lead which connect coil via R13 to pin 6 of U101a!That lead must
be connected to gnd in coil!
I am using cable with 3 separate leads and common shield. Shield and 1 lead are connected to
faraday cage at both coils...all togather in coil housing. The other 2 leads i am using for
TX and RX....Simple as that. No twisted pair effect,no hums,interferences...no false signals!
I experimented with any other combination and this one is best.
Nelson, no you can not use only 3 lead cable....Shield and 3 leads yes! It makes 4 leads at
the end.
LM308 is hard to replace...beleive me! Only replacement i would use is TL081a...
About Bipolars....i never used those. I connect 2 ordinary 10uF cpacitors like this;
+ -- + and used those instead...
No, Nelson...if you using TLxx1 no need to reroute pcb; pin to pin compatible...
About NE5532...i am not sure...why dont you try NE5534? I never tried it...
OK. Again there is (i hope) very correct schematic...at the end. Take another look.
If something wrong let me know...
Anybody migh have good will to draw pcb for it? One-sided,small...C'mon....

[ivconic]

No ideas..

???

Hello,
Ivconic~!
Are you shore that I can change LM308N with TL081?And will this afect the preformance?
Also I cant find LF353 any Ideas?
Did you use 10 mF TANT or you used normal electrolithic?
Thanks

[ivconic]

???


Took another look at it, and...YES! KT315 is right! I traced pcb again.
Yes KT315 you are right! How i missed that!!!??? I have few different
schematics here....I payed attention on wrong one...Shhheeeeeesh!!!
Bravo KT315 and thank you!
But about loading resistor you mentioned...? I am not sure? Yes i can agree
with you, there must be loading resistor...but it is not there? And device is
working excellent!?
I corrected schematic and here is now; i really hope complete and accurate!
Porkluvr....Yes double O coil showed best results so far...but i gave up of those!
Why? I am gonna explain why; not so suitable on terrains i've been visitng lately.
There are a lot of bush arround,tree roots all over arround, high density opsticles
and OO coil is not just suitable enough to approach to every spot;under some tree or
between some stones...when coinshooting. I do that mainly...coinshooting.
So i made hard compromise and switched back to DD (double D) coils, again...
Double D shape is much more suitable for that kind of prospecting than double O.
But if you prefer leveled terrains than i suggest you to make OO coil cose a bit
greather depth than DD coil.That was my only reason to leave OO coils for now...
No i didnt say "...no gnd connection on RX..." !? Yes there is gnd connection on RX!
Must be! But not at pcb. That's why i didnt draw gnd connection in schematic.Not to
confuse somebody who might decide to draw pcb according my schematic...Later should
scratch or cut that piece of pcb to correct mistake...
GND connection at RX should be made in coil.
Pay attention on cable lead which connect coil via R13 to pin 6 of U101a!That lead must
be connected to gnd in coil!
I am using cable with 3 separate leads and common shield. Shield and 1 lead are connected to
faraday cage at both coils...all togather in coil housing. The other 2 leads i am using for
TX and RX....Simple as that. No twisted pair effect,no hums,interferences...no false signals!
I experimented with any other combination and this one is best.
Nelson, no you can not use only 3 lead cable....Shield and 3 leads yes! It makes 4 leads at
the end.
LM308 is hard to replace...beleive me! Only replacement i would use is TL081a...
About Bipolars....i never used those. I connect 2 ordinary 10uF cpacitors like this;
+ -- + and used those instead...
No, Nelson...if you using TLxx1 no need to reroute pcb; pin to pin compatible...
About NE5532...i am not sure...why dont you try NE5534? I never tried it...
OK. Again there is (i hope) very correct schematic...at the end. Take another look.
If something wrong let me know...
Anybody migh have good will to draw pcb for it? One-sided,small...C'mon....

[nelson]

Previus post

Hi Ivcoic, again i was reading other electronics post that talks about LM308 replacements. One, the TL071 seems to be correct, but don´t know if i have to rerouted on the PCB.
There is another replacement that needs to by rerouted.
Please teke a look to the following posts.

Are you modifying a stock pedal or is this a DIY build? If it is a stock pedal you should just go back to the LM308 or use an LM071 with the compensation cap removed, you can't really do any rerouting with the PCB.

Otherwise, the LM308 pins are as follows:

1- Compensation
2- IN -
3- IN +
4- V- (GND)
5- NC (No connect)
6- OUT
7- V+
8- Compensation

The NE5532P is:
1- OUT1
2- IN1-
3- IN1+
4- V-
5- IN2+
6- IN2-
7- OUT2
8- V+

Basically, if you were going to reroute things, you'd have to use only one half of the NE5532P, and map pins as follows, LM308 to NE5532P:
6 - 1
2 - 2
3 - 3
4 - 4
7 - 8

And remove the cap connecting pins 1 and 8. Not an easy job. You'd really have to design it to use that OA.


Yes the pins would be different for a 5532 dual and a 308. I used 741 and it sounded pretty good which ignored the compensation caps.

You can"t use any of those 3 Opamps in place of the LM308...You need a Single Opamp not a Dual opamp and all of the Opamps you have bought are Dual opamps...A good replacement might be a OPA134 (You bought a OPA2134 which is a Dual opamp) and the LM833 which you bought is a 1.5w dual Power Amp IC which isn"t suitable either and the RC4558 is also a Dual opamp.....

Look for a OPA134 or a TL071 or a NE5534 , These are all Single opamps and there are Literally Hunderds of different types that could also work but also thousands of others that won"t work....

You should spend some time reading the Datasheet specs of these Opamps so you know what to look for when you need to replace them.....


Cheers

This post can be found on

http://www.diystompboxes.com/smfforum/index.php?topic=52733.msg399102

My english is not so good, but has i understood, TL071 will fit my needs.
Thanks and best regards
Nelson

Hi ivconic, today a got almost all components for golden sabre.
Only need to get 4.7 uF caps and LM308N.
Do you know if there are any replacement for LM308N.

About the coil, i´m thinking on using audio cable with shielding on it (3 cables). What do you think, is this correct?
In advance many thanks
Regards
Nelson

[nelson]

Parts replacement and coil construction

Hi ivconic, today a got almost all components for golden sabre.
Only need to get 4.7 uF caps and LM308N.
Do you know if there are any replacement for LM308N.

About the coil, i´m thinking on using audio cable with shielding on it (3 cables). What do you think, is this correct?
In advance many thanks
Regards
Nelson

Here some photos...

[Qiaozhi]

Hello Qiaozhi-

I'm already here so let me resond. If CD4066 were used to gate the signal to x and r channels a pull-up to +5V would be required. Instead, these JFETs will turn on with zero volts on the gates, and use an "active low" to turn off. I think it's kind of neat how that works out! The FETs are actually pulled up from -5V, to 0V.

Thanks. After I posted the reply I noticed that all the other Golden Sabre schematics (except one) were also tied to 0V.

[porkluvr]

FET pull-ups

Hello Qiaozhi-

I'm already here so let me resond. If CD4066 were used to gate the signal to x and r channels a pull-up to +5V would be required. Instead, these JFETs will turn on with zero volts on the gates, and use an "active low" to turn off. I think it's kind of neat how that works out! The FETs are actually pulled up from -5V, to 0V.