DOD 250/MXR dis+ goodness

Started by MmmPedals, March 21, 2010, 10:49:57 PM

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MmmPedals

Just put two DOD 250's (slightly modified) in series on the breadboard. UM UM high gain goodness and everything in between. two of these in a box seems like such an obvious idea. anyone do it before?
I love the idea because its circuit that can be used as a simple boost to pretty crunchy rhythm and with 2 of them you can get some serious lead tones.
Only problem is the lm741 isnt exactly the quietest chip. What would you you suggest for a drop in replacement thats quieter?

MikeH

If you're making 2 of them use a dual opamp like a 4558 or TL072.  Tonepad has a project file for 2 microamps on one board; which you could use to make 2 250s- just add a volume pot at the end with the clipping diodes strapped across the volume pot.
"Sounds like a Fab Metal to me." -DougH

MmmPedals

I want them to be switchable independently i.e. a/b/ab. how would i pull that off with a dual opamp?

BAARON

Using a dual opamp just means one half of the op-amp is in one circuit and the other is in the other.  They're still independent of each other, except that everything's built onto the same circuit board.
B. Aaron Ennis
If somebody makes a mistake, help them understand what went wrong.  Show them how to do it right.  Be helpful.  Don't just say "you're wrong, moron."

MmmPedals

How do i figure out which pin of the 4558 (or other dual opamp) equals which pin of the original schematic?
The 741 uses only pins 2,3,6, and 7. So which would those relate to on each side of the 4558?

kupervaser

Single:


Dual:


Compare and you will find it!

MikeH

Quote from: MmmPedals on March 21, 2010, 11:28:35 PM
I want them to be switchable independently i.e. a/b/ab. how would i pull that off with a dual opamp?

I think this project will bring the possibilities to light.  First look at a micro amp and a dist+ schematic side by side, and then look at this double micro-amp project file:

http://www.tonepad.com/project.asp?id=28
"Sounds like a Fab Metal to me." -DougH