Need help, crackling vol knob on amp

Discussion in 'Community Discussion' started by joecool85, Nov 26, 2005.

  1. joecool85 macrumors 65816

    joecool85

    Joined:
    Mar 9, 2005
    Location:
    Maine
    #1
    I just picked up a Fender Sidekick Bass amp (30w, circa 1987) and both the volume and master volume knobs crackle like crazy when turning them, sometimes if you don't push/pull at it just right it won't even make noise really...I'm assuming there is nothing you can do to repair a potentiometer, so should I just put in two new ones? Should I do it myself or have someone else do it? (I'm good enough at electronics to make my own pedals, I'm more worried about the electricity stored in the caps in the amp.)

    Also, anyone know what resistance/taper pot to get for it?
     
  2. Blue Velvet Moderator emeritus

    Joined:
    Jul 4, 2004
    #2
    Prob full of dust -- just replace them, they're pretty cheap. The specs will probably be written on the back of them.
     
  3. toontra macrumors 6502

    Joined:
    Feb 6, 2003
    Location:
    London UK
    #3
    Spray with switch cleaner & turn rapidly until the crackling (hopefully) stops. Works for 90% of all old/dusty pot crackle problems.

    Try Servicol. Always a can found in recording studios! (in the UK anyway)
     
  4. joecool85 thread starter macrumors 65816

    joecool85

    Joined:
    Mar 9, 2005
    Location:
    Maine
    #4
    If I was to replace them or even play with the inards of the amp, shouldn't I be worried about zapping myself?
     
  5. toontra macrumors 6502

    Joined:
    Feb 6, 2003
    Location:
    London UK
    #5
    You don't need to go anywhere near the "innards" - switch off, unplug, pull the plastic knobs off & carefully spray the spindle.
     
  6. joecool85 thread starter macrumors 65816

    joecool85

    Joined:
    Mar 9, 2005
    Location:
    Maine
    #6
    $10 for cleaner...shouldn't be a whole lot more than that for new pots...I think I will just go through the process of draining the caps and then solder in a couple new pots. I will probably end up being a lot happier with the end result. And thats what really matters.

    On a side note, it looks like I might build myself a 4x8 cab to go along with it.
     
  7. joecool85 thread starter macrumors 65816

    joecool85

    Joined:
    Mar 9, 2005
    Location:
    Maine
    #7
    Well, now I'm unsure if I'm going to build a 4x8 or a 4x2 cab. Who knows?

    Back on topic, I ordered up a couple 10k linear pots for the amp, got em from jameco. I found out that tube amps are really the old ones with crazy dangerous voltage inside, not solid state like this is. This one only has up to 36 or so volts, it'll hurt, but shouldn't kill. That and it won't arc as much as hundreds of volts.
     
  8. ToddW macrumors 6502a

    Joined:
    Feb 26, 2004
    #8
    don't fool around too much. voltage is still voltage, whether it is 36 or even 110, it hurts. I work in a lab that has quite a bit of exposed voltage everthing from 2.7 to 270 volts. And as many accidents I have seen and a few that have happened to me, voltage is nothing to mess around with. The good thing about it being solid state is that the you only have to worry about the caps on the power supply portion of the amp (this is the part that converts AC/DC) that is the only thing that should shock you. just as long as you unplug it and wait a few minutes everything should be fine.

    I rebuilt an old fender twin reverb about five years ago, found it at a garage sale and made a killing after a rebuilt it. still wish i had that amp. the good news is that fender's tech guys are really cool with helping you find schematics and stuff.

    be sure and research your parts wisely. some pots are better than others. not all pots/caps/opamps/resistors are the same. research for quality components and the amp will sound really good. i recommend panasonic pots, they are really good and cheap. Oh yeah and do a 4x8 cab for it that will really be sweet. just make sure and wire the speakers up right. i can't tell you how many cabinets i fixed just because the speakers are wired funky. also use gold wire!
     
  9. joecool85 thread starter macrumors 65816

    joecool85

    Joined:
    Mar 9, 2005
    Location:
    Maine
    #9
    Gold wire? Where would I get that? And can you solder gold?

    Anyway, I ordered up a couple pots from Jameco. Had to get them there because I couldn't find a 10k linear with a knurled top anywhere else. Whatever. I want this amp to sound ok, but I'm not horribly worried about it since it was free :)

    The 4x8 may or may not happen depending on how I feel/how much money I want to sink into this. Cool thing is, if I build a nice 4x8 I could use it on something else. With the speakers I'd be using it would take 100wRMS so I should be able to hook that up a lot of different pa/amp combos.
     

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