Question about the Minelab Sov and Elite

[Sean Goddard]

Re: Active circuit in coil.

Thanks for confirming this Carl. ;-)

[Henry (OR)]

Re: Active circuit in coil.

Mr. Bill is right. Thats sounds logical to me. I am also a an electronic tech, self employed and been detecting nearly 30 years now. The output on detectors are usually in the 1/10th to maybe 2/10th of a watt. Though .1 to .15 watts is common. Only one output transistor, usually a low noise audio amp transistor is used usually coupled with a resistor of 1% tolerance to keep the output stable. Since power is very low, one of those ICs may just be a transmitter. I am not sure that Minelab wants anyone to know the ins and outs of their machines. Garrett is the same way. won't realease schematic unless the unit is 20 years old or unless you are an authorized repair center. Some "secret" might get out that only 15 years old!.........Henry...ps....one other thing that most people don't know, is that even though the Sov and Explorer send out multiple signal at once, they can only process the info from TWO frequencies at a time. The question is,.....which two? What 2 frequencies are you actually getting info from? Just thought I would share this.

[Norbert]

Re: Question about the Minelab Sov and Elite




Hello Solmer!

Is it possible to trace the circuit diagramm from the board.

I think the NE5534 is for amplifying.

LM394 is a Supermatch Pair of two transistors

[Sean Goddard]

Re: Well that sure doesn't look like the Tx section!!!

I reckon Minelab use some VERY creative imagination when it comes to advertising.

An alternative could be that they are full of s**t.

It is true that a lot of false claims are allegedly made with respect to the workings of their machines, and indeed, some people claim great success with them, whilst others do not. This is due to the way in which the so called "multi frequency" machines choose which "channel" they use during the setup after switch on.

The Sovereign seems only to be able to tune to TWO frequencies out of it's alleged 17. The new Elite does this dynamically, and I know of a lot of people who have upgraded to get this feature.

I'm sorry but I have to say "You've wasted your money" in a lot of respects, as the old Sov XS2a-Pro can also do this. If working a site and you start to get interference, simply switch off, wait 30 seconds then switch on and wait a short while, and the machine will automatically retune to a NEW pair of quieter frequencies.

The Explorer does this with the machine switched on. This is what the "Noise Cancel" facility does. It forces the machine to search through it's range of channels to find the quietest set to use. Problems arise from this as the frequencies it tunes to may NOT be those which are optimum for finding Gold or Silver.

The Whites DFX for example only has two frequencies, both of which are chosen for a VERY specific reason. No chance of going "off optimum" there then.

Depending on the soil and environmental conditions the Explorer can choose three wholly inappropriate frequencies and thus give some users very poor performance.

[David]

Re: Question about the Minelab Sov and Elite

On the original sovereign there are 6 pins on the control box coil connector. Two of these pins are ground one is a receive input and two are transmitter outputs from a bridge circuit made up of four power transistors and an additional four driver transistors. The last pin comes off the output of an op amp that is the final stage in a circuit that supplies the Id signal. It's all on the main board you can monitor this pin with a scope or volt meter and see the levels change with different targets. The coil contains a LT1028 ultra low noise pre-amp. There is no power wire connected to the coil. The + and - voltages for the LT1028 are obtained from a bridge rectifier circuit connected across the transmit coil. The power for the ID meter must be obtained the same way, this is why the cable daisy chains through the ID meter. This also makes the cable softer because it dose not apear to have stiff shielding. A lot of the gain is at the coil so I believe the signal impedance on the cable is lower and less chance of amplified noise.