Potentiometer locking knobs?

Discussion in 'The Workbench' started by adew1, Sep 27, 2020.

  1. adew1

    adew1 New Member

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    Anyone used these for an external bias adjustment pot, to prevent the pot shaft moving when the amp is in transit, etc? If so, any idea where I can get some? Seaches on Digikey and Mouser haven't been successful, probably because I'm not using the correct terminology.

    Thanks!
     
  2. thetragichero

    thetragichero Well-Known Member

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    loknob is a brand of em
    feel like they made that as a solution to a problem no one had

    is your bias pot in a position where it's going to get moved around a lot?
     
  3. anitoli

    anitoli Well-Known Member Gold Supporting Member

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    Bias for all practical purposes needs to be in a certain range specified by the tube type, it can be higher or lower as long as its between two points. It really isn't that critical to an amps operation to micro manage the bias adjustment. You don't need to check it every week or worry about it. Set it and play the amp.

    Tubes will let you know when they need attention, usually the first sign is sound degradation.
     
  4. adew1

    adew1 New Member

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    Thanks for your replies.

    @thetragichero It will be on the top of the chassis. Thanks for the suggestion re Loknobs. I'll look into those.

    @anitoli Sure, understood. However, if I want to micro manage, as you put it, the bias setting, so what? That's not why I'm asking the question. I just want peace of mind that the pot doesn't get knocked out of position, and a locking knob seems a way to address that.
     
  5. Rudy v

    Rudy v Well-Known Member

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    You can use something like this Z-PC10KBIAS-10k-lin-Loetoesen-orig-CTS-USA-Biastrimmer-1_200x200@2x.jpg
     
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  6. Gunner64

    Gunner64 Well-Known Member Gold Supporting Member

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    I know that when I build an amp I put the bias test ports on the backplate, and the bias pot on top of the chassis. With the back metal grill on there is really no way to bump the pot out of adjustment...works for me.
     
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  7. Im247frogs

    Im247frogs Well-Known Member

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    I’ve used the slotted 10k linear pots for fender style builds, but in my most recent amp a used a big old beefy PEC 50k pot and put a Tele knob on it. I have to reach around the choke to adjust it, it’s never going to get knocked, and the pot has a lot more torque than anything I’ve used before. Piece of cake. It’s a Princeton chassis so the whole rig is flipped. 2890B64A-5E51-4B1F-B7F2-6D7CAD7A5167.jpeg CD26DF1A-161B-4F5A-8CDC-258418F08894.jpeg
     
  8. Chris-in-LA

    Chris-in-LA Well-Known Member

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    That’s one beefy PT!
     
  9. Im247frogs

    Im247frogs Well-Known Member

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    It’s an Allen drop-in Princeton reverb upgrade so I can run 6v6, 5881s, 6L6s, EL34’s. B+ is a bit high for 6v6s but I like it w the EL34s at the moment.
     
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