10 turn potentiometer or not for ground balance?

[yatahaze323]

Quick question, would a 10 turn potentiometer that big of a difference compared to a regular potentiometer for ground balance?

Just trying to figure out if I should buy some or not.

[Tibuck19]

I used them because I thought it would of made a big difference, but in all honesty, I didn't find it to be anymore advantages over a normal pot, plus its a lot harder to ground balance if you turn it a few turns to many on either side. Maybe it would be on difficult soils but not for normal.

[Carl-NC]

I find a 10-turn to be too much, but a 1-turn not enough. Tesoro got it right with a 3-turn pot but they're rare & expensive. Still, 10T is better than 1T.

[green]

I have a 1 turn pot to set different target delay times(marked at 6, 10 and 14usec). Have been using a 1 turn coarse and a 1 turn fine for ground balance. The coarse pot is marked to ground balance for 6, 10 and 14usec target delay times then balance for ground signal with fine pot. I would look for a 10 turn dial pot instead of just a 10 turn pot if target delay is adjustable.

[Koala]

I used a 10T yes its over kill on a Bandido.

Yes it can be slow to adjust. Most of my fields are fairly similar so once adjusted for one its not too bad.

But at the end of the day it worked well.

[blobber]

For me is working well, a 47K trimmer for basic adjustment and a 4k7 potentiometer in series for fine adjustment GB, on my Bandido2.

[kt315]

I find a 10-turn to be too much, but a 1-turn not enough. Tesoro got it right with a 3-turn pot but they're rare & expensive. Still, 10T is better than 1T.

i had wrote an offer to do 3t pot to a manufacturer in aliexpress. will copy his answer.

[Tibuck19]

I find a 10-turn to be too much, but a 1-turn not enough. Tesoro got it right with a 3-turn pot but they're rare & expensive. Still, 10T is better than 1T.

A 2 or 3-turn would be much much better. Who manufactures them? or are they a in house made by Tesoro ?

[Hyena]

I use series of for example 47k resistor - 10k potentiometer - 47k resistor as substitute for 100k potentiometer for more precious adjustment. It might have too small range when you change coils. When I know I will use only one, you can make any range for pot you want.
Or 100k trimmer on board for coarse in series with 10k pot on front panel for fine...

[green]

I have a 1 turn pot to set different target delay times(marked at 6, 10 and 14usec). Have been using a 1 turn coarse and a 1 turn fine for ground balance. The coarse pot is marked to ground balance for 6, 10 and 14usec target delay times then balance for ground signal with fine pot. I would look for a 10 turn dial pot instead of just a 10 turn pot if target delay is adjustable.

Like blobber(reply #6)my fine pot is 1/10 the resistance the coarse pot. I have some hot ground from California that balances the same as the ground in my back yard. Having a dial pot would give an indication if a different ground didn't balance at the same setting or something was changing with the detector. Probably not worth a big cost difference(maybe 10%). If the dial setting was 7.50 turns(dial pot displays 750) to balance ground, adjusting a regular 10 turn pot 2.5 turns back from full CW would be the same. A mark on the knob might do the same.

Should different grounds balance at different settings with a PI detector if the other timings don't change?

[Carl-NC]

A 2 or 3-turn would be much much better. Who manufactures them? or are they a in house made by Tesoro ?

Bourns, maybe others. They run $20-30 each, unaffordium. Look to eBay and Alibaba for reasonable prices. Also consider 5-turn, those are out there, too.

[yatahaze323]

Thanks everyone for the input. It is difficult finding the 3 and 5 turns pots, the few I've found don't go up to 100k. Plus just like Carl said they're expensive!

Besides our metal detectors what other applications would these pots be used in? Just wondering if I could scavenge some from old equipment.

Also would the coarse/fine concept that blobber and green be a mentioned be a better option?

[Tibuck19]

Thanks everyone for the input. It is difficult finding the 3 and 5 turns pots, the few I've found don't go up to 100k. Plus just like Carl said they're expensive!

Besides our metal detectors what other applications would these pots be used in? Just wondering if I could scavenge some from old equipment.

Also would the coarse/fine concept that blobber and green be a mentioned be a better option?

If your in the United states this could be a good deal, https://www.ebay.com/itm/BOURNS-3510...jkPV:rk:4:pf:0 sadly for me, after exchange and shipping and import fee's it as expensive as buying from mouser or Digikey.

[Tibuck19]

Would the 3 Turn pots be worth using for threshold and discrimination pots ?

[Koala]

Would the 3 Turn pots be worth using for threshold and discrimination pots ?

not for me

however those cheap and nasty small POT's are terrible. The larger wattage ones tend to be much smoother.


turning up the thresholds as per several YouTube videos is a waste of time in my opinion. The only thing it does is make faint signals louder. great on a video when using the speaker. But in real life using headphones you loose the pinpoint and the ability to judge the depth.

Once the threshold is set to a faint hum. Your good to go. I mark the dial so I can see if it accidently get knocked you turn it back to the mark really it doesn't need to be on the front panel unless you detect wet beach when I turn it down slightly.

I do alter the disc slightly from field to field. A !T POT has an adjustment that fine enough for me.