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Audio Circuit too sensitive

Discussion in 'Audio' started by Diggar, Feb 27, 2017.

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  1. Diggar


    Dec 22, 2016
    Hi I have in ceiling sound system in my office. I am connected to Sirius radio to play in house. The receiver is connected to an amplifier as you can see from the photo.

    The device was built by someone to make it work but it is way too sensitive. In other words when I need a little more volume if I change the amplifier volume even slightly it blasts the volume in the ceiling speakers.

    That is a B100K pot. So I am not sure if the resistor is too small or too big or what I need to do to fix it.

    Any help appreciated

    Attached Files:

  2. Arouse1973

    Arouse1973 Adam

    Dec 18, 2013
    Hi Digger
    Can you find out if the POT is linear or logarithmic? The use of a linear POT instead of a log pot could be the cause.
  3. BobK


    Jan 5, 2010
    You have to make sure the signal going in is in the right range for the amplifier. Are you using a microphone input? They are far more sensitive than an AUX input or LINE input and should not be used except for a microphone.

  4. Diggar


    Dec 22, 2016
    The pot on the connection is audio taper

    Thanks for all the advice so far
  5. Bluejets


    Oct 5, 2014
    As Bob says, you are probably overdriving your amp with the input signal.
  6. Audioguru


    Sep 24, 2016
    I have a cheap clock radio and a Sony Walkman radio that have volume controls with intermittent levels when adjusted. I suspect the crimp between the ground terminal and the resistive track makes a poor connection. When the volume is turned down a little then it goes to full blast.
  7. 73's de Edd

    73's de Edd

    Aug 21, 2015

    Sir Diggar. . . . . . . .

    CONFIRMED . . . .
    Newer potentiometers will usually be marked with an "A" for logarithmic taper.(for volume control use ) or a "B" for linear taper.
    And we can see that mini unit which you show is being a B100K LINEAR taper. .
    Changing to an audio / A taper will present a more s..t..r..e..t..c..h..e..d out adjustment range of the volume within about the first 90 degrees of adjustment and then it speeds up . . .such as you are currently / immediately experiencing on your using that B taper unit . . . . . .. Its gots a hair trigger ! ! ! .
    That amp seems to be a Chinee wannabe / knock off of a Fender 25 amp.
    That shown input jack being used is for the FEEEEEEBLE input level of a guitar pick up so even when using the prior log pot, it will still require sone touchy setting of both the cascaded VOLUME and GAIN controls of that unit.
    You are probably inputting in the order of a raw 1/2----1 volt of audio into the unit PRIOR to your pot which you are wanting to use.
    Comparatively . . . a HARD plucked open D string may peak out at ~ 150 millivolts .

    73s de Edd
    Last edited: Feb 28, 2017
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