dood 250 / mxr micro amp

[numpty]

I have a dod 250 which i would like to change to a mxr micro amp clean boost, the circuit looks the same although values do differ somewhat, do I just loose the diodes and tone stage to achieve a clean boost or will i need to change some the caps and resistors which are not the same as the micro if so which ones

[Ben N]

This ought to give you some idea of parts substitutions: http://www.tonepad.com/getFile.asp?id=6

[Mark Hammer]

Leave the ground side of the two diodes and the .001uf cap connected together, and install a SPST (or better) toggle-switch between that point and ground to make/break the connection.  That will engage/bypass the clipping.

Like the Distortion+, the DOD250 uses a .047uf cap on the "ground leg" leading up to the Gain control.  Use of a cap that small results in progressive loss of bass as the gain is increased.  Normally, this would have several consequences for the DOD250/Dist+: a) with gain increased, any hum from single-coil pickups would not be amplified quite as much, and b) the tone would become more "piercing" at higher gains.   If that capacitor value is increased, there will be much less bass loss at higher gains.  That will certainly make "clean" boosts more like a Micro Amp (which is flat).  What it will also do is hit any clipping diodes with a bigger signal, since much of the signal lives in the bass end.

So here is what I will suggest.  If there is room (and I believe there is) you should be able to install two small toggles in the pedal.  We've described the first one above.  The second will be to insert a 2nd or 3rd cap in parallel with the .047uf cap so that you can revert back to stock when you want, or else have one, or possibly 2, additional degrees of bass available to produce different  overdrive or clean sounds.

If you only get a SPST to fit the space, use it to switch in a .1uf cap in parallel with the existing .047uf unit.  That will get you a parallel combined value of .147uf, resulting in a bass rolloff starting around 230hz at max gain, which isn't too bad.  At lower gains, that will be closer to flat response.  If you were to use a SPDT "on-off-on" toggle (which may end up being a bit too big to fit the available space, depending on which one you get), I'd suggest switching a  .039uf in parallel in one position and a .1uf in parallel in the other.  The .039uf in parallel gets you a combined capacitance of .094uf, which gets you a rolloff starting around 390hz, which will be different-sounding from the stock rolloff as well as the "audibly flat" rolloff, and just the perfect thing if you want to play clean but want something juuuust a little less "woofy".

[numpty]

Thanks thats a great help, I shall do as you have advised space isn't a problem as it in a bigger box than normal