Sensitivity Adjustment Question ...

[Willee - Texas]

I have a Minelab SOV XS-2a that will run max sensitivity at the beach without chatter.
Is there an internal adjustment that will kick it up a bit more.
I would like to have it so that the front adjustment knob would make it chatter when set to max.
It can always be cut back a bit.

 

[MatthewS]

Eh... that would depend on how the sensativity is controlled. Assuming the POT is placed in the feedback loop for the op amps, an increase in value would reduce the feedback even more and thus the op-amp would have a higher gain. It's not know for a fact, but it couldn't hurt to assume that and try something simple.

On the sensativisy pot, looking at the rear, should be the wire on the farthest left. Note the value of the POT itself, Ie. 50k. Detach that far left wire and insert a resistor between that wire and the terminal it attached to. For the value of the resistor try starting at 10-20% of the overall POT value. For example if the POT is 50k thats 50,000 ohms. Now 20% of that would be a 10k resistor. This would allow an additional 20% of 'overdrive'

Now that brings us to two things here. Try not to go over 20% overdrive and secondly there is no guarantee that the op-amps are not already overdriven at max sensativity to begin with. But whatever that pot value is, take 20% of that, find a resistor as close to that as possible and add it as suggested. That should allow you 20% more gain adjustment assuming the op-amps capable and the topology is correct. If you do this, report back with your results.

- Matt