Sunday 3 February 2013

DOD FX53 - Classic Tube




13 comments:

  1. Getting closer to the fx56... It is a shame that they all lost the battery doors on these. Some of them sound great.

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  2. You can verify this. I built it yesterday. Works as it should.

    /Mortua

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  3. Hello, sires!
    I'm having some issues with this one. The tone pot "works" only in the extreme positions (doesn't do anything to the sound in between). I've tried pots with lower and higher values, but though the overall tone changes, function remains the same.
    The other issue is that when the drive is maxed the pedal starts to squeal. That one's not too big of a problem since the squealing starts only when the drive is maxed.
    Any advices?

    Thanks!

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    Replies
    1. I can't help with your tone pot issue - not sure what is going on there, but I own an original one of these, and the last eigth of a turn on the drive pot is a "boost" and it does get very loud, very noisy and tends to induce instant feedback from my guitar.

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    2. Hey I have a similar problem with mine, also with my volume pot, It does sound really low. Did you find out a work out with yours in tone pot?

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    3. I put my build on the shelf for now. I'll be looking into it in the near future, since I'm troubleshooting some other builds as well. I'll post any solutions here if I end up resolving that tone pot thingy.

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  4. Ok, thanks for the heads-up, Beaker! :)
    The noise that my build makes is not feedback, but it's a distinct squeal. Self-oscillation, mayhaps? There are few other distortion pedals I've built from Mark's and Miro's layouts that tend to squeal when the drive / distortion is maxed, so it's not nothing new to me. Not to say there's something wrong with the layouts. It's just more expectable that some distortion builds have the tendency to squeal.
    Like I said, it's not something that would bother me TOO much if I were to leave it like it is, cause 95% of the drive pot's range is still perfectly usable :)
    But the issue with the tone pot is something I need to get a solution for.

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    1. Even though this thread has been silent for years I'll throw in a few lines about what I've found. So, the tone pot was useless to me, that was the largest single problem of this build. I found a schematic of the circuit and found out that the tone section here is different. In this layout both ends of the tone pot go to ground through resistors and caps, but there's no link to the output of the opamp (IC2 / pin 7). In the schematic there's a 100nF cap from the IC2 / pin 7 to Tone-3.
      Also, in the schematic the 3k3 / 1uF combo going to Tone-1 are 6k8 / 100nF AND 3k3 / 22nF going to Tone-3 are 3k9 / 10uF.
      I haven't tested this out yet, but I'm going to soon.

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    2. Forgot to mention that the 120pF feedback cap between IC2's pins 6&7 is 3,9nF in the schematic, so there's a difference also.

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    3. Darn, a correction to my previous note:
      "...the 3k3 / 1uF combo going to Tone-1 are 6k8 / 100nF AND 3k3 / 22nF going to Tone-3 are 3k9 / 10uF." -> that 3k9 going to Tone-3 is 3k3 in the schem. So, Tone-3 -> 3k9 -> 10uF -> GND.

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    4. Ok, now I tested change to the sound and the schematic version IS (supposedly) the correct one! The tone pot functions as it should without major "dead zones" and the overall sound is more useable (although I had to swap Tone-1 and Tone-3 to get the pot to work "logically"). Like Beaker noted there, when the drive pot is dimed, there is a boost-like bump. This also work better now and there's no squeal.
      Only thing that would be nice is more volume :D Now it's un unity with clean signal. Maybe changing the volume pot to a different value...

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  5. Thanks man that helps a lot for im planning to built this one.

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