TESORO GOLDEN SABRE

[nakky]

sound

Hi Nelson,
I've some 50 ne5532... tested there and it's not good (for me) as replacement this time, at least for my taste: lose many performances... and TL072 is better than it this time.

I have NE5532 originals by Philips.

If you have dubts, buy one and see with your eyes.
Very easy to find and cheap.

What I'm talking about is not just related to noise at preamp. but have more to do with input stage of op. amp. that is a very tipical fingerprint expecially for jfet inputs op. amp.

That's why I've indicated the analog and TI replacements.

I've tested 566 circuit (the one you can see in Sasho's thread, with bc547 and bc557, but arrows are in wrong places... anyway) I'm not so happy of results... get sound and VCO operations, of course, but sound it's not loud as I want. Think that a TBA820M could solve any problem of loudness.

Yes, LM566 is almost impossible to find. My new 3 pieces were from an old 80's stock. I'm sure somewhere is possible to find it from old stocks unselled products, but it's a hard challenge not for anyone to get this stuff.

Best regards,
Max

Hi Max,play with the 33K for sound.Grt Nakky.

[Max]

where they are... on the PCB

[Max]

Hi,
yo make things more clear, the differences you see:

- red : what I consider real mistakes, that could affect circuit working (or part of it working as expected e.g. battery checker)
- green : just a mod. for tuning and not really a mistake

Some mistakes are in schematic only, like 150pF and resistor connection to diode, or 47K resistors... others are in PCB (e.g. 5pF instead of 10pF) but I've indicated in schematic to have a reference there.

Best regards,
Max

[Max]

Hi,
I think that there are just few relevant things in that differences I described in the schematic using green color.

I think most important is that capacitor between pin6 and 6 of 353.

If you change values of this you have different freq. response of preamp.

I've mounted 5pF, like in PCB-chart, but I'm a bit puzzled and think that maybe correct values is 10pF for it. I'm not sure... of that, and also side effects could be really small for real.

But I think it is in a really "hot spot".

Also the 33k resistor that is 2K2 in PCB is not a real "error".

What to say... maybe it was 10pF ! But my detector works fine with 5pF!
So I'm not worried too much of this...

I'll check it, anyway, in next days.

Another funny thing is the 470ohm in schematic that become 470K in PCB,
at battery checker.

Best regards,
Max

PS: a big mistake was the 150pF cap ! But already corrected much time ago.

[Max]

Hi,
Max.
I think that I reach around 26 cm with unshielded coils.
The sound is from 8 ohm speaker/I now its no good,but..../!
But when you detect there are terains that dont alaud to keep search head close to the ground,so this is not so good result.
But its more than many expencive toys!'
I will try to achive better results.

Well done. Keep tuning now.

[Max]

MAX, WHAT YOU CAN GET IF YOU CHANGE THIS COMPONENTS HAS IS SHOW ON THE SCHEMATIC AND NOT THE PCB?
ALSO, I UNDERSTAND THAT GOOD RESULTS OBTEINED BY YOU AND IVCONIC ARE WITH COMPONENTS SHOW ON PCB SCKETCH, RIGTH?, CAUSE I DON´T WANT TO BE CONFUSED AFTER I FINISH MY 22 CMS COIL, SO BY NOW I HAVE PLAN TO DO MY TEST WITH THE ORIGINAL PCB SET UP.

REGARDS

NELSON

Hi Nelson,
I've done modifications of component list as indicated in an above post.
But just for active devices and some spare:
- 4xBF244B in middle section (sampler) instead of BF245C (changed pinout of to-92)
- 2xBF245C in battery checker and osc section
- 1xLF353 as preamp (but tested others)
- used 2N3904/2N3906 instead of 2N2222/2N2907
- 1xTLC2262 instead of TL062
- 1xC517 (not BC, but it's the same stuff, pinout etc)
- 1x8ohm speaker

+ 2xTL081 instead of LM308

Just these of above, not resistors or caps or diodes. I followed the PCB labels, so mounted e.g. 5pF between pin 6 and 7 of 353, not 10pF as in schematic.

Change e.g. of fets or bip.-transistors if not a big change really. About same thing. LF353 as preamp. as described, and just 3 IC mod (tlc2262 instead of tl062, 2xtl081).

So don't worry. About the same.

Best regards,
Max

[tiktak]

Hi

Hi,
Max.
I think that I reach around 26 cm with unshielded coils.
The sound is from 8 ohm speaker/I now its no good,but..../!
But when you detect there are terains that dont alaud to keep search head close to the ground,so this is not so good result.
But its more than many expencive toys!'
I will try to achive better results.

[nelson]

MAX, WHAT YOU CAN GET IF YOU CHANGE THIS COMPONENTS HAS IS SHOW ON THE SCHEMATIC AND NOT THE PCB?
ALSO, I UNDERSTAND THAT GOOD RESULTS OBTEINED BY YOU AND IVCONIC ARE WITH COMPONENTS SHOW ON PCB SCKETCH, RIGTH?, CAUSE I DON´T WANT TO BE CONFUSED AFTER I FINISH MY 22 CMS COIL, SO BY NOW I HAVE PLAN TO DO MY TEST WITH THE ORIGINAL PCB SET UP.

REGARDS

NELSON

Hi all,
found another difference from schematic to PCB !

How many! Why ? Who knows ?... but it works good... so nevermind!

Difference is:

in schematic between pins 6 and 7 of LF353: cap =10pF
in PCB same cap is instead =5pF

Kind regards,
Max

Here is the map of misteries...

[Max]

Hi all,
found another difference from schematic to PCB !

How many! Why ? Who knows ?... but it works good... so nevermind!

Difference is:

in schematic between pins 6 and 7 of LF353: cap =10pF
in PCB same cap is instead =5pF

Kind regards,
Max

Here is the map of misteries...

[Max]

Hi,
About equiv. noise voltage vs freq typ (at 1KHz):
(and not considering load...)

LF353 : 16nV/sqrt{Hz} (data from National's datasheet)
TL062 CN : 42nV/sqrt{Hz} (data from STmicro's database)
TL072 CN : 15nV/sqrt{Hz} (data from STmicro's database)
TLC2262 CP: 12nV/sqrt{Hz} (data from TI's database)
NE5532 : 5 nV/sqrt{Hz} (data from Philips' datasheet)

So seems that 5532 beat all the others... well NO. On equiv. noise YES, but there are other things to keep in mind when playing with an RX coil signal.
This is not a microphone or guitar preamp...

So one have to consider other things too.

Kind regards,
Max

[Max]

http://www.diystompboxes.com/smfforu...8954.msg461001

If you have NE5532 please try to change with 353 and see the differance.

And this 566 is inposible to be found!

Hi Nelson,
I've some 50 ne5532... tested there and it's not good (for me) as replacement this time, at least for my taste: lose many performances... and TL072 is better than it this time.

I have NE5532 originals by Philips.

If you have dubts, buy one and see with your eyes.
Very easy to find and cheap.

What I'm talking about is not just related to noise at preamp. but have more to do with input stage of op. amp. that is a very tipical fingerprint expecially for jfet inputs op. amp.

That's why I've indicated the analog and TI replacements.

I've tested 566 circuit (the one you can see in Sasho's thread, with bc547 and bc557, but arrows are in wrong places... anyway) I'm not so happy of results... get sound and VCO operations, of course, but sound it's not loud as I want. Think that a TBA820M could solve any problem of loudness.

Yes, LM566 is almost impossible to find. My new 3 pieces were from an old 80's stock. I'm sure somewhere is possible to find it from old stocks unselled products, but it's a hard challenge not for anyone to get this stuff.

Best regards,
Max

[nelson]

Hi tiktak and Max.
Tiktak, my last 22 coil, is the same made by Max and now is giving me the correct values on inductance and resistance. So this weekend i ll play chanhing leads connections to get rigth on phase.
I also had a terrible mistake, when i discover that my rx cap value was wrong. This was around 10 pF and the correct value needed is 15nF, so i replaced it and the detector is working good by now and only need little work to go has Ivconic and Max said.
So i recomend you, to take the time to do all advices that Max is telling you. The main obstacle was passed, that is building the detector and make it work. Now you need to find were is the fault to correct it.

Regards

Nelson

Hi tiktak,
about coil 18cm for 1eur is low. But maybe problem is not at coil, maybe some mistake in circuit.
Also you have to exchange rx leads at each test you made... cause if no right phase you'll lose performances.
I swear, that my GS detector detect in air 1eur coin at 27cm, with DD22 without any tuning... even geb in mid position! I had no time for testing and tuning at best now. Coil is the same of bandidoII, no mods., nothing.
So try swap rx leads, sometimes there is the problem; if not you maybe have some wrong thing on PCB.
About TEA2262 is not same of TLC2262, it's another thing (used in TV sets and old VCR, switching power supplies).

If can't find TLC2262 you maybe could find TS27L2 or TS27M2 that are not so well but have much less noise than TL062.

Kind regards,
Max

[tiktak]

Hi

http://www.diystompboxes.com/smfforum/index.php?topic=58954.msg461001

If you have NE5532 please try to change with 353 and see the differance.

And this 566 is inposible to be found!

[tiktak]

Hi

Look at this:

Had anyone ever compare the electrical charateristic of TL072 to TLC2262?
What is the thing make 2262 produce lower noise ?

other than 072, What other chip is comparable to 2262?






Re: TL072 compares TLC2262 « Reply #1 on: July 05, 2007, 07:01:58 AM »

At 9v there will be no difference, but at + & - 15v possibly, but probably not losing any sleep over!



I think that there are no mistakes when I check!
I give it attention.
May be flux as you say,but I doubt!I will try to wash with acetone!
Thanks

[tiktak]

Hi,

I think that the probleme is in coil!
Can you tell me what you think for NE5532 it should be very good to be used according to data that I have.
Low noise....