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Help with modding a Rat!

Discussion in 'Effects [BG]' started by Gonzo476, Oct 7, 2013.

  1. Gonzo476


    Mar 1, 2009
    Madrid, Spain
    So I just got a Turbo Rat in a trade and I want to take it to a local modder. So far I've thought of three things:

    1) Increased low-end. I know people around here perform the Ruetz mod, but, from what I've read, that smoothes out the sound of the pedal, something that I'd like to avoid. Are there any alternatives?

    2) Add a switch so I can have LED clipping (stock Turbo rat)/no diodes (this is what ''standard'' rats have, right?)

    3) Change the stock op amp for the infamous LM308. I'm not sure about this one because on a Youtube video I saw the LM308 gave the rat kind of a softer sound. Is that right or are my ears/headphones deceiving me?

    Befores anyones says it, I'm sure the modder has a solution for some of these problems, but I'd like to get some insight from my favourite bass playing, pedal geek community :bag:
  2. Crater


    Oct 12, 2011
    Dallas, TX area
    I HAVE NOT DONE THIS MOD, but: an alternative is to increase the value of all coupling capacitors in the signal path, doubling their value. Change the 22nF caps to 47 nF...this will allow more bass frequencies through, but will also change the character of the pedal, don't know if it would be an improvement or not. :oops: There is also a 4.7 µfd and 10 µfd electrolytic caps in the signal path, but those are probably big enough already.

    No, standard RATS use a very common silicon diode (1N914 diodes) for clipping. No diodes will increase the volume and headroom, making the RAT more of a boost. You could install a center-off toggle switch and choose between standard clipping diodes, LED clipping diodes, or no clipping diodes.

    That's probably correct, and why people like the LM308. It's an early design of op-amp, and doesn't have the best technical specs, namely the "slew rate" which is how fast it can follow a signal. A lower slew rate means less shrill/fizzy upper treble tones. Some people say it makes a difference, others say it doesn't. :meh: Just solder in an 8-pin IC socket, it makes it easy to change out op amps and experiment.
  3. nolageek


    Jan 5, 2011
    Washington, DC
    How about adding a blend circuit so you can keep the rattiness but dial in some of the source to keep the low end?
  4. rratajski

    rratajski Commercial User

    Jul 1, 2008
    Mount Laurel, NJ
    I will go against adding a clean blend to any RAT. It takes away from the sound in a mix. Visit Beavis Audio Research to see the resistor replacement mod.

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