by gaussmarkov

Rat Layout

I sold my original Rat long ago and had to make another. tonepad.com has great layouts and I have learned from them. I always lay the circuit out from scratch and see how different mine turns out to be. Thanks to Henrik Jakobsen for correcting an error in a previous version. The schematic source is tonepad.com.

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16 Responses to “Rat”

  1. RedGuitar said:

    i will try to do it

    Posted 10.07.2008 at 2:35 am

  2. Hugo Gutierrez S. said:

    I just doit and I changed the IC by a LM741. Only I had to do a little change to use it with this IC. Great sound.

    Posted 05.09.2008 at 10:29 am

  3. philippe said:

    hello, I am of the pcb rata “tonepad”, is there a mistake or error ? I have the resistance of 47 ohms heating “entry 9v ” I have no error or solder components … thank you for helping me !!!

    Posted 06.10.2008 at 5:08 am

  4. thren said:

    “Out” is pin 2 of the volume pot I take it ?
    PS: been enjoying your site.
    Just finished a UV LED exposure box, so time to make some PCB’s.

    Posted 28.11.2008 at 4:22 am

  5. gaussmarkov said:


    yes, you are correct: out is pin 2 of the volume pot.

    cheers, paul

    Posted 28.11.2008 at 6:43 am

  6. Zeke said:

    instead of 30pF cap will it be okay if i use a 33pF cap?

    Posted 15.06.2009 at 1:09 am

  7. chingchongchinaman said:

    no you must apply noodles to your fore head…this will resilt in much fortune in the pedal making department…..

    wise words for today..

    man maketh pedal for no man is rich
    in his soul until he builds dr boogie…

    Posted 24.06.2009 at 9:28 am

  8. rob said:

    yeah i ‘ll go along with that….ching chong chinaman….already built two..

    Posted 20.10.2009 at 4:54 pm

  9. Facundo said:

    Hello gaussmarkov / Paul, I have a question, I hope not to disturb.
    I want to remove the control “filter” the RAT and replace it with a tone control tri-band (bass-mid-trebble).

    my question is, what components should I remove? (100k potentiometer obviously = P)
    R7 (1.5k)
    c8 (0.0033uf)
    c9 (0.022uf)
    and r8 (1M)
    Or am I wrong?

    Thanks so much.
    Facundo from Argentina:)

    Posted 01.11.2009 at 9:17 pm

  10. alfan said:

    hi gauss …

    i just finish build the proco rat clone by this schematic.but why the distortion not clean as the original rat? i have the original rat too …and by the A/B test the original rat has more smooth sound too.

    please help …thanks.

    Posted 23.02.2010 at 10:07 am

  11. alfan said:

    …continue from my older post.

    there’s ringing or some artifact on my proco rat clone,its heard when i add the distortion,even only a bit.

    how to remove ‘ringing’? thanks.

    Posted 23.02.2010 at 11:11 am

  12. nesar morgan said:

    i ned voltages parts

    Posted 11.01.2011 at 5:00 pm

  13. bob said:

    first time builder where do i put
    the negative of the battery clip

    Posted 03.08.2011 at 4:21 am

  14. Leo said:

    Awesome and easy build, thanks Gauss!

    Posted 29.09.2011 at 2:29 pm

  15. Kodiak said:

    If i am right is the transistor Q1 wrong connected in the PCB, because the gate should be connected to the resistor R8.
    Assuming you are looking from above it is the drain which is connected to R8.
    But i have other problems. I only get a noise from the OPV. Input ( + and – ) and the output is in the static conndition nearly the half of V_cc so that should be right. Does anyone have an indea, where the failure can be?

    Posted 15.10.2011 at 5:55 am

  16. Simon said:

    I own a turbo-rat that I modded to a ‘normal’ one and it sounds just great. Just replace the LED’s by two 1N4148 diodes!

    Anyway I just simulated this with LTspice and its real fun! I even noticed that you can use a 2N5457 instead of a 2N5458. Just in case someone needs a replacement type!

    LM741’s are also OK, but i find LM308 sounds better but oh, thats just a simulation and my gusto… 😉

    Posted 24.03.2012 at 12:35 pm