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Tuesday, July 3, 2018

Pigtronix Fat Drive

Here's an interesting one from Pigtronix. It uses a TL072 to push a CD4049, which is followed by another TL072 pushing a Rat-esque tone control. All the gain stages make for natural compression and tube-like tone without using clipping diodes. Schematic for reference on FSB here (note, I've linked the inputs of the unused stages of the CD4049 to +9v to avoid any unwanted noise). Runs great on 9 or 18 volts and will fit in a 1590B with board mounted pots.


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8 comments:

  1. John GovanJuly 3, 2018 at 12:05 PM

    Can you make a bass preamp like mxr bass preamp pedal.

    ReplyDelete
  2. andresguevaraJuly 15, 2018 at 2:44 PM

    Good morning team, I look for MXR M81 preamp layout !!!!!, thanks and success.

    ReplyDelete
  3. bluesanderlJuly 26, 2018 at 8:46 PM

    Hi everybody!
    I build it, ( the pcb version) and it worked from the fist Time !
    Sounds Great! I Used the part values from the layout, but substituted the 130k resistors with 120k ( couldn,t get some)
    Another fantastic layout, trank you very much!!!
    And i think you can Mark this as verified!

    Greetings from Austria

    ReplyDelete
  4. UnknownAugust 13, 2018 at 3:59 PM

    CD4049BE will work??

    ReplyDelete
  5. wainer.said@gmail.comMarch 18, 2019 at 8:59 PM

    What should I change to the bass version.
    https://www.youtube.com/watch?v=RMEcY1hIF0c

    ReplyDelete
  6. DerekFebruary 14, 2022 at 12:55 PM

    Can I use a single TL074 instead of the two TL072 IC's by routing the pinout in the following way? I wanted to ask before I go spending a couple of hours breadboarding. Even if it works at first, I may run into problems down the road.

    IC1:

    TL074 PIN 1 ->[---]<-TL074 PIN 4
    TL074 PIN 2 ->[---]<-TL074 PIN 7
    TL074 PIN 3 ->[---]<-TL074 PIN 6
    TL074 PIN 11->[---]<-TL074 PIN 5

    IC2:

    TL074 PIN 8 ->[---]<-TL074 PIN 4
    TL074 PIN 9 ->[---]<-TL074 PIN 14
    TL074 PIN 10->[---]<-TL074 PIN 13
    TL074 PIN 11->[---]<-TL074 PIN 12


    I would of course be doubling up on the VCC+ and VCC- by "sharing" the input and output for both IC's into the one TL074.

    ReplyDelete
    Replies
    1. Effects LayoutsFebruary 14, 2022 at 1:07 PM

      Yeah, in theory that should be fine. Though you only need to run power and ground from one of the TL072 locations to the TL074. The only other issue you might run into would be the circuit may be a little noisier with having all the opamps in one package instead of 2 like the original. Sometimes it's an issue with higher gain circuits.

      Delete
    2. DerekFebruary 14, 2022 at 2:46 PM

      Oh, that makes sense—since the power and ground only run one unit. Thanks!

      Delete