I'm chasing info on the pinouts and connector used for Sovereign

[Geo]

Also Heriberto must keep the same phase between Tx and Rx. If he loose the phase he will loose the discrimination

[betobrambi]

thanks my friends IBGold and Geo

Thank you very much, IB Gold and Geo...

I will take it into account ... Then, I will have to maintain the same inductance and resistance than the search original coil Minelab ...

Many friendly thanks mine, Alexis told me that here a true family is necessary to he helps ...

I do not know like to thank them so much help ...

Now, on Monday ... I go for looking for somebody that I manufactured the PCB Gramophone preamp ( circuit diagram ) that provided our friendly Mike, I design of Walter Jung ...

I will have to search, because I do not know that he would make the plate this way, in Manzanillo, Colima. Mexico ...

Thanks ...
Best regards

[kt315]

thanks Mike for the coil schematic that longly did not give me a pokoj.

this is a sound for you now... in your Honour!

http://beemp3.com/download.php?file=...e+On+The+Water

[mikebg]

The attached picture is the same circuit of Sovereigns front end as in posting # 2.
In my (not humble:-) opinion, there is something wrong in the design, especially the capacitor 0.6uF shunting TX coil.
In principle Sovereign is wide band metal detector. That means the designer should avoid coils stray capacitance and should use damping with coil resistance and shunting resistors. Damping is made for RX coil with shunting resistor R3. Note that damping is easy because RX coil has no cable capacitance.
However the TX coil has cable capacitance. The TX coil is damped by its own resistance 22 ohm and resistances of saturated transistors T1 ... T4. Even without shunting capacitor 0.6uF, these resistances are not enough to avoid ringing because cable capacitance is significant. Note that 22ohm appears too high resistance for TX coil because limits TX current.
The shunting capacitance 0.6uF worsens damping prosess of TX tank circuit causing TX current to ring at frequency about 180Hz. This frequency appears third harmonic of mains frequency 60Hz, however it is useless even for suppressing magnetic viscosity.
Is this the real circuit inside sensing head?

[kt315]

The attached picture is the same circuit of Sovereigns front end as in posting # 2.

no, not same. 0.6 uF sits in RX coil, not in TX. thanks again.

Note that 22ohm appears too high resistance for TX coil because limits TX current.

this is so-called high resistance coil - must find out those mentions from Eric Foster. he uses them in his last designs.

[Altra]

Mike that "600n" is a 680pf and the TX coil is about 1mH at 1 ohm.