Pedal Experts/builders - I need (1) LF442 OpAmp

Discussion in 'Effects, Pedals, Strings & Things' started by RockStarNick, Feb 22, 2012.

  1. RockStarNick

    RockStarNick Supporting Member

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    Hey guys,

    Well, I'm in the middle of repairing a MXR CAE401 Boost Line Driver. Trying to save a few bucks doing it myself, and learning some things in the process.

    Narrowed down a bunch of possible problems. Replaced 2 suspect components, and still not working. Total cost so far: $3.

    Stopped in at a local electronics specialty shop, and they suggested that the opamp might have blown.

    The problem is: they didn't have a replacement for me. And I really don't want to spend $5-10 on shipping for a small part like this.

    Does ANYONE on here have a single LF442 opamp, or equivalent, that they could throw in the mail for me?

    Your help is much, much appreciated. Thanks!!!

    - nick
     
  2. Jack DeVille

    Jack DeVille Member

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    Spend some time to trace out the circuit fully, then logically troubleshoot the circuit.
    Thorough diagnostics will save you both time and money.
    I don't want to sound harsh, but here's the honest truth: throwing parts at a fault may result in rectification, but it will likely result in longer repairs, increased parts costs and the inevitable uncertainty of the potentially completed repair.
     
  3. AL30

    AL30 Member

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    A quick search gave some info on your chip. You should be able to sub in a TL072, LM833, or LM358. The TL072 is common.

    I agree with Jack. Finding what's wrong with it -specifically- will take a bit longer (maybe) but you'll learn a good bit in the process. Having said that an audio probe is a fantastic tool to have around. It's a cheap, quick and easy build.

    http://www.diystompboxes.com/pedals/debug.html

    http://diy-fever.com/misc/audio-probe/
     
  4. cj_wattage

    cj_wattage Vendor

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    Seems like TL062, TL072, or TL082 will be fine subs. You can get TL082 at most Radio Shacks in the parts bins.
     
  5. RockStarNick

    RockStarNick Supporting Member

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    Guys, thanks so much for the info. That Debugger wire looks like a great thing to have around - I'm going to throw one together tonight.

    Where are you finding this info on opamp substitutions, anyway?
     
  6. cj_wattage

    cj_wattage Vendor

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    I just the part number. The description is "low-power JFET-input dual op amp". There are lots of subs for that. :aok
     
  7. RockStarNick

    RockStarNick Supporting Member

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    Thanks guys. I know I'm not going about this from the proper perspective. I just want to get it up and running, for as little cash as possible.

    Learning somethings along the way are a welcome bonus.
     
  8. cj_wattage

    cj_wattage Vendor

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    I could probably just send you a couple different op amps that would work. Or if you're close enough to me, we could meet. I'm in your general area. :)
     

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