OneAcre Posted August 5 Share Posted August 5 Has anyone succesfully added a volume control for the MXT E-Tracker's speaker? If so, how? Recently I've been using enjoying the therapeutic simplicity of my older bfo and tr type machines for shallow targets in the parks carrying only a pinpointer and probe for recovery. Volume control is necessary to avoid attention, oddly my older machines have this feature. I already have volume controlled earphones as well as an inline earphone volume control for lightweight headphones when doing serious hunting with the MXT. Something that could be spliced in the positive speaker wire would be nice. 1 Link to comment Share on other sites More sharing options...
OneAcre Posted August 8 Author Share Posted August 8 There are only a couple sites that i could find showing this. This one uses a 1k pot: https://m.youtube.com/watch?v=kkSe9hAtCZ4 This one uses a 1k pot as well: https://www.instructables.com/Garrett-ACE-250-MOD-VolumeLCD-LightGround-Ballance/ A couple forums recommend a 10k pot. The speaker on the Whites MXT is 16ohm / 0.3watts if that helps. Some say it is better to place the pot at the amplifier rather than the speaker. It seems controlling at the speaker should work well since headphone volume controls are made that way. I was hoping for someone with experience over time to weigh in verifying the workability of this preferably on the MXT 2 Link to comment Share on other sites More sharing options...
Sven1 Posted August 10 Share Posted August 10 You can try a 5K or a 10K Audio taper pot. One will one will silence the speaker at 1/2 a turn and the other at a full turn of the pot Keep it simple and use this diagram to wire the pot. An connect to the wires that run to the speaker. 5 Link to comment Share on other sites More sharing options...
Sven1 Posted August 10 Share Posted August 10 There should be a volume control trimpot on the circuit board, you could remove it and replace it with an external pot of the same value. The value will be a code on the trimpot. This would be the correct way to do it. The volume control will also control the volume of the headset when it is plugged into the detector. The diagram is from a White's detector. 1 Link to comment Share on other sites More sharing options...
OneAcre Posted August 10 Author Share Posted August 10 Sven... Have you or anyone you know performed this mod on the MXT? My only fear is there may be a good reason why there are no verified volume mods for the MXT that I can find. This detector has special meaning for me or I would just do the mod to find out. Your response is MUCH appreciated, it's more an overabundance of caution than a lack of trust. 1 Link to comment Share on other sites More sharing options...
locator Posted August 10 Share Posted August 10 18 hours ago, Sven1 said: You can try a 5K or a 10K Audio taper pot. One will one will silence the speaker at 1/2 a turn and the other at a full turn of the pot Keep it simple and use this diagram to wire the pot. An connect to the wires that run to the speaker. That will be the way I'd do also, Sven. A pot like R61 for volume control, shown in the second image you posted, isn't available on the MXT layout. @OneAcreGo with Sven's solution and use a 10K. This will not damage the electronics, but be careful where you mount the pot so that nothing is touched by the connections or the pot itself and thereby short-circuited. 2 Link to comment Share on other sites More sharing options...
OneAcre Posted August 11 Author Share Posted August 11 What is the reason for grounding the pot? On the linked video this was not done. 1 Link to comment Share on other sites More sharing options...
locator Posted August 11 Share Posted August 11 3 hours ago, OneAcre said: What is the reason for grounding the pot? On the linked video this was not done. The reason for this is that this is always regulated with defined working points. The other solution simply changes the resistance. If the current is no longer sufficient, the loudspeaker is silent and the control is left more to chance. The fact that it looks like the potentiometer is grounded is purely a coincidence. That's my explanation, but someone else may be able to explain it more clearly. 2 Link to comment Share on other sites More sharing options...
OneAcre Posted August 11 Author Share Posted August 11 Locator... Your explanation makes sense. It led me to the attached thread clarifying the difference between a rheostat (controls current) and a potentiometer (controls voltage). https://www.physicsforums.com/threads/potentiometers-vs-rheostats-or-why-a-pot-needs-a-ground-connection.686710/ Based on the advice of you and Sven1 it looks like the 3 wire circuit is the one to use. By the way, thanks to Locator for the massive Whites literature link. Thanks to Sven1 for the vintage literature on the treasurelinx/geotech site. Also noticed Steve Herschbach's thumbs up on my original post, thanks for all the MXT info. I may not comment here much, but certainly visit often. Thanks to all. ...OneAcre 2 1 Link to comment Share on other sites More sharing options...
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