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Thread: Various pot values for analog read

  1. #1

    Various pot values for analog read

    Hi all,

    I'm working on a Teensy synth, and I just realized that the slide potentiometers that I want to use are not available in 10K or 5K linear format. (Almost every other variation is available but not 10K or 5K for some reason.).

    I'm curious what difference it makes in accuracy/noise/current draw to use different pot values for a basic analog read circuit. (There will be 8 of these sliders hooked up to various analog inputs.) I've heard that 5K and 10K are ideal for Teensy, but I'm wondering how much of a real-world difference it would make if I were to use 20K, 50K, or 2K pots in this basic analog read circuit.

    This feels like a very generic question, so I apologize if it's been answered before. Thanks for any advice!

  2. #2
    Senior Member
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    @toutant:

    In my <<TeensyMIDIPolySynth>> project (original version - I've since converted to using a 7: RA8875 display with all of the pots simulated on the display), I had 48 pots (each 50K) which were all wired thru 74HC4067 MUXs & sampled (one pot read per pass thru the loop() function) via analog reads. I've seen comments in other threads indicating that higher resistance can result in higher noise on the input, but my setup seemed to work without too much extra noise from the pot/pin sampling. In my case, I wanted to minimize the amount of current wasted thru all of these pots wired across the T4.1's built-in 3.3VDC regulator.

    Hope that helps . . .

    Mark J Culross
    KD5RXT

  3. #3
    Thanks, Mark! And congratulations on the MIDIPoly. It's a really cool project that I've borrowed from a few times .

    That's good to know. I've read that higher values might case extra noise, but haven't experienced it yet with 20K pots. I guess I'll trust my ears.

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