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New BYOC Mighty Mouse (RAT) kit on the way (will build to MO'D specs)...

Discussion in 'Effects, Pedals, Strings & Things' started by Deaj, Jan 15, 2008.

  1. Deaj

    Deaj Member

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    I've been busy building pedal projects over the last few months and my projects are starting to grab real estate on my pedal board (sweet). I recently built a GGG Tube Screamer kit and modded it to L'DO specs. It turned out great and it's beginning to look like it may push my Eternity off the pedal board These two pedals are not so similar that having them both is redundant. I'm just not using the Eternity much since the modded TS/L'DO moved in. I've also recently completed a fantastic sounding EA Tremolo circuit build from the schematic posted at Runoffgroove.com and a Jordan Bosstone fuzz clone that absolutely rocks!

    The next project will be a distortion pedal, specifically a RAT derivative. I just received notice that the new BYOC Mightly Mouse kit version is available. It's basically a vintage RAT circuit with a 6-way rotary switch with six different clipping options. I ordered one this afternoon and also placed a Mouser order for the necessary components to build this kit to Landgraff MO'D specs (+ several clipping options). I was already beginning to source the parts to build a RAT/MO'D but the cost was getting close to the price of a kit and the BYOC kit offers some additional flexibility. I'll be sure to post more when the build is complete.
     
  2. nibus

    nibus Supporting Member

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    Sounds interesting. I'd love to hear your comparisons of your completed projects and the actual Landgraff pedals.
     
  3. Scrutinizer

    Scrutinizer Member

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    Very cool, I'm looking forward to the build reports.

    I recently completed an old-style BYOC Mighty Mouse. Very happy with the results, sounds great. I am now debating whether I should add extra toggle switches for more clipping options ... or simply order & build the new BYOC kit.
     
  4. Deaj

    Deaj Member

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    You could rig a temporary switch and try out each of the clipping options with the pedal open to see if you like any of them. Then you could wire the ones you dig to toggles and mount them. It would definitely be cheaper than buying a whole new kit. Of course the build is fun and the rotary switch would make switching options simple. Fun either way! :BEER
     
  5. Guitar Josh

    Guitar Josh Resident Curmudgeon Silver Supporting Member

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    Simpsons (Freakshow) Did it.
     
  6. erikm5150

    erikm5150 Member

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    Deaj,
    I'm looking forward to hear your report on this build...

    I'm also planning on getting the BYOC rat soon and do some mods to it...

    If you don't mind sharing, what are the Landgraff MO'D specs for the RAT?
     
  7. Deaj

    Deaj Member

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    I received a Mighty Mouse rev.2 kit today and finished the build late this afternoon. I am not that familiar with the RAT pedals but I became interested after hearing some sound clips of the Landgraff MO'D. I decided to build a BYOC Mighty Mouse stock and then mod it to MO'D specs. I recently did this with a Tube Screamer kit (GGG ITS8 kit) - built it stock then modded it to L'DO specs (polyester film caps, carbon comp resistors in the audio signal path, a few component value tweaks, and the three-way clipping selector). The comparison was most interesting and the resulting pedal is fantastic! I'm hoping that I'll find similar results with this project.

    So far I'm pretty impressed with the Mouse, most specifically with the 'overdrive' clipping settings (positions 4, 5, & 6 on the rotary switch). I also like the distortion settings as well but I find gain settings above 12 o'clock to be overly bassy (is this a common characteristic of early RAT pedals?). At or below 12 o'clock the distortion clipping options all sound great. I do find the filter control to be somewhat limited in terms of useable range (I've read that this is true of vintage RAT's as well) but inside that useable range there's plenty of flexibility.

    I'll spend some more time playing with the Mouse in stock form and then I'll get to moddig it to MO'D specs. I'll make the following changes:

    * The 47ohm resistor from the 9vDC supply will be increased to 100ohm.
    * The 1Mohm resistor to ground at the input will be removed.
    * The resitors in the audio signal path will be swapped out for carbon composition type resistors.
    * The .01uF film cap to ground before the transistor will be decreased to .001uF.
    * The two 4.7uF and one 2.2uF electrolytic caps will be swapped out for tantalum type caps.
    * The .1uF electrolytic cap just before the volume pot will be swapped out for a film type cap.
    * The two pF ceramic disc caps will be swapped out for silver mica type caps.
    * The 33pF compensation cap will be increased to 51pF.

    The MO'D appears to have all 1/2w CC resistors throughout. I doubt that this has any more than a negligible effect on the overall tone. I decided to use CC resistors in the audio signal path to stay as close to the MO'D specs as possible but leave the rest of the metal film resistors in place to mitigate noise. The tantalum and silver mica caps should smooth the gain a little. This should be to my liking - I like smooth dirt pedals!

    I located two separate hand traced schematics of a Landgraff MO'D - both were identical and reportedly verified. I have no way of knowing with certainty but I'm pretty sure the information is accurate. I used these schematics, posted gut shots of a MO'D, and the BYOC Mighty Mouse schematic to determine the required mods as listed above. There are two areas where the physical order of a capacitor and resistor are reversed. These two changes could be made to the BYOC kit but the mods would be complicated and messy. There's no point really since neither is likely to have any sonic impact to the circuit.

    I'll be sure to post more once I've completed the mods. In the meantime has anyone else found the low frequencies a little over the top with the gain past 12 o'clock? Have you implemented any circuit changes that have successfully tamed the low end at high gain settings without disturbing the balanced tone at low gain settings? Perhaps this will improve with the MO'D mods but, unless the 51pF compensation cap effects the circuit in this way I rather doubt the other changes will. Guess I'll find out soon enough. [​IMG]

    Here are a couple of pics of the completed kit:
    [​IMG]
    [​IMG]

    Since I don't have access to a Landgraff MO'D I won't be able to make any kind of comparison. The most I can to is provide my own subjective opinion regarding any improvements realized by these mods.

    More to come...
     
  8. erikm5150

    erikm5150 Member

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    Thanks for sharing this info!
    I also saw you post at the BYOC forum with the mouser part numbers and the diagram -- great stuff!
    Now i really can't wait to try this out!
     
  9. jb1911

    jb1911 Member

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    Why would you want to mod this pedal to Landgraff MO'D specs when you have never even heard one? I know people that think the MO'D has some bad value choices that actually make it sound worse than if you've left it like a stock Rat. This makes no sense. Is the MO'D just considered superior because it costs more? Please fill me in on your decision, I am genuinely curious, not just trying to cause trouble here. Thanks.

    PS. I am really curious about this pedal and will probably get one so I really appreciate your doing this review.
     
  10. fr8_trane

    fr8_trane Member

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    I would avoid CC resistors like the plague in a high gain pedal and opt for low noise metal film. All CC's add is noise and 20% tolerance in a 9v circuit. You need to be running at 300v + before any marginal mojo factor becomes possible.
     
  11. Deaj

    Deaj Member

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    To be honest I'm not familiar with either the stock RAT or the Landgraff MO'D. My intention was to build the kit stock first and then modify it to MO'D specs for comparisons sake. I had some time to become familiar with the sound of the kit built stock. Then I made changes incrementally and listened at each step. The results? Well, the gain is a touch smoother with the tantalums and silver mica caps (output cap type changed from electrolytic to poly film as well). Carbon comp resistors? No appreciable difference (resistors were 5% tolerance and measured so close to the metal films they replaced that no difference was realized). There appears to be no appreciable increase in noise with the CC resistors in place. Changing the compensation cap value from 33pF to 51pF increased midrange a touch - not for better or worse, just different. I really like both configurations and haven't made any permanent decision yet. I'm still experimenting with this circuit. It's a great sounding drive pedal regardless! The kit is well worth the coin as it offers a lot of flexibility.

    I'll post more later. :)
     
  12. tonefreak

    tonefreak Member

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    Modding with your ears and not your eyes... excellent!

    I wouldn't have chosen CC resistors personally because of the noise shelf, but if you're just changing a few out, then you probably won't notice a whole lot of difference than if you built the entire pedals using CC resistors.

    Regardless of what name you call the mods, modifying a pedal to your liking is always a fulfilling endeavor. I highly recommend socketing the points of interest next time out... if you haven't done so already. It makes changing out the components and A/B testing the results much easier.

    Have fun!
     
  13. Deaj

    Deaj Member

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    I just received some new sockets. They'll go in when I next open the pedal. Fun stuff! :AOK
     
  14. blue_lu

    blue_lu Member

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    so how did the mo'd mod turn out?
     

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