Potentiometer 4K, balance, 1/4 turn

Discussion in 'General Electronics Chat' started by luis9191, May 31, 2015.

  1. luis9191

    Thread Starter New Member

    May 31, 2015
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    Hi everybody!

    This regulates the balance between an electric-organ's 2 keyboards, say upper keyboard vs lower keyboard.

    I haven't found anything like that at semiconductor-stores (I live in Mexico). http://1drv.ms/1d6Oa1J

    I'd appreciate your oppinions. I'm open to any suppliers or ideas. ;)
     
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
    1,066
    How about a buffer amplifier where you feed the two audio sources to the ends of a simple linear pot, and feed the wiper to the buffer. This makes a linear balance network, where the relative amount of the two sources is directly proportional to pot position.

    227.gif

    To go from 100% of one source to the 100% of the other source requires turning the pot ~270deg. It is possible to "amplify" the middle part of the pot rotation, but it would be a more complex downstream circuit and I will have to think about how to do it...
     
    Last edited: May 31, 2015
  3. ian field

    Distinguished Member

    Oct 27, 2012
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    Looks a bit like a stereo pot for a car radio, not exactly an off the shelf item but not impossible.
     
  4. luis9191

    Thread Starter New Member

    May 31, 2015
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    Wooow! That surely sounded like u know what you're talking about... hehe just kidding, I'm afraid I'm not that electronic-guru (only know how to weld and highschool level knowledge)... but what I did get... sound kinda satisfiyng :D . Just to go on about that idea, I was also thinking about welding a "resistor in parallel" to reduce the Ohms, cuz stock items are only 20K ohms and if you're way too lucky you might find 10K Ohms.

    The 270º sounds genius But I'm afraid the "equilibrium/center" position might have too much resistance and neither keyboard would sound, and not even understand how 0-90º angle would give me the ~4K Ohms I'm looking for.

    I totally agree, there's no stock item like it, and yes also, i guess a "stereo pot" would work, but didn't find any under that description either.
     
  5. luis9191

    Thread Starter New Member

    May 31, 2015
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    Gentlemen... I drew this. I guess this is how it works... hope comes in handy ;)

    Have a nice week!:cool:
     
  6. ian field

    Distinguished Member

    Oct 27, 2012
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    If its simply a matter of simultaneously controlling the amplitude of 2 similar signal sources, a couple of voltage controlled amplifiers might solve the problem.

    The old favourite was the CA3080 that's unobtaneum now, an alternative is the LM13700 - which I think is 2 units in one package.

    Another possibility is the TDA7052 with the A suffix which incorporates a DC controlled volume, its actually a BTL audio power amplifier, but you can use just one of the outputs in single ended mode at greatly reduced power - but more than enough for small signal use.
     
  7. luis9191

    Thread Starter New Member

    May 31, 2015
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    tnx 4 replying!!!

    How do you google those codes? I'm only getting chips [​IMG] ...or should a new circuit be built? I'm afraid I'm not that techy electronic guy and seriously not so eager to learn a new major, hehe. :eek:

    Sorry for "dodging" it, here's an Indie-Apple-amp video (skip to 4:01, the HTML didn't want to do it)
     
  8. luis9191

    Thread Starter New Member

    May 31, 2015
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    At the end I replaced it with another one. Didn't quite fixed it, but at least is working.

    Anyway Tnx guys!!!
     
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