Bright switch on preamp

Discussion in 'General Electronics Chat' started by Treeman, Mar 26, 2015.

  1. Treeman

    Thread Starter Member

    May 22, 2014
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    15
    Good evening,
    Att. is a schematic for a 3BandEq I have made that I have dutifully stuck in a tin with a preamp I have wanted to build for 20 years!
    It sounds great through my WF55 DIY amp (20 years excitement not wasted) and really helps shape the sound but the bright switch does not work. It may be that I am misunderstanding the wiper attachments on the Bass and Middle pots. Does the arrow indicate that VR2 wiper is connected to C3 and VR3 wiper to ground or the other way?
    All the wiring seems to check out OK so could it be the wrong part specified?

    Thanks.
     
  2. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
    1,438
    368
    The bright switch is there to enhance the high frequency output as the level of VR4 is reduced. If VR4 is set at max, the bright switch will have no effect but you should hear something with VR4 in its mid position.

    If you connect the wipers or VR2/3 to the wrong end, the controls will work but in reverse.
     
    Treeman likes this.
  3. Treeman

    Thread Starter Member

    May 22, 2014
    158
    15
    Thanks Blocco. Its always the simple answers eh! If the switch is there to get over the resistance effect of the pot then I guess that if there is little to no resistance then the effect is limited! Thanks for the lesson in how to deduce from electronic texts. No guitarist would have thought to turn it down.
    The wipers have worked from either end at various stages in the build LOL.
    Thanks.
     
  4. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    You turned it all the way up to 11, right?
     
  5. Treeman

    Thread Starter Member

    May 22, 2014
    158
    15
    Well yes - When I built it , it came with no instructions but a large banana. The banana makes gripping the dials difficult so I just left it at 11. Not that there are numbers either.
    Cheers!
     
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