Help with LoFo Mofo

[robertsbri]

I just finished my second build, the LoFo Mofo. I got the ready to soldier board from General Guitar Gadgets because my first shot did not come out so well. Well the darn thing still won’t work! It is a really simple build and I was wondering if someone could take a quick look at the schematic and see if anything jumps out as being something a first time builder may miss. I was thinking maybe I have the diode backwards but the negative band is going to the ground. I am also a little confused by the ring, tip and sleeve of the jacks. I moved a couple wires on the stereo jack and it made the light come on when I hit the switch and the volume knob worked then, but the distortion knob does nothing. I really want to be able to do this but seeing I messed up on this simple one I am getting afraid for my next project a scrambler clone.

Here is the layout I followed for the LoFo

http://www.generalguitargadgets.com/pdf/ggg_lofomofo.pdf

[Bernardduur]

At first the negative band of the diode should NOT go to ground, the positive should.

Second, on the jacks only two sections are needed:
A- hot (or tip) wich transfers the signal
B- cold (or ground) on wich the ground is connected.

Therefor connect all grounds to the ground of the jacks (one and connect that to the other) and keep it separated from the tip (else leakage and no signal!).

Here is a bit of a schematic. I normally work with these things. http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html#lofomofo Hope it works

[robotboy]

Check the FAQ section on pot wiring and refer to the schematic referenced above to make sure you've got it right.

http://www.diystompboxes.com/cnews/FAQ.html

The diode should be wired across the lug 1 of the pot and the wiper (middle lug) with the stripe facing towards the wiper.

[markr04]

And just in case you don't know how to count the legs of a pot:

with the shaft/knob side facing you and the legs at the bottom, they are 1,2,3 (L-R).


( o )
/  |  \
1  2  3

[Pushtone]

Oh, Oh, a teaching moment...

I could not get the DISTORTION control to work on my LoFoMoFo. Sound is nasaly and hissy as per the description, but DIST knob does nothing.

I'm thinking it because I subbed the 1N5817 diode with a common 1N4148.
So when it didn't work I looked up the 1N5817.
Schottky Rectifiers? Whats a Schottky Rectifiers?
Is this a special diode that can't be subbed? Or did I get something else wrong?

[Bernardduur]

The diode is wrong, that is the main fact. The 5817 is a rectifier diode, a 4841 a switching diode. Replace them and the unit will work.

[tiges_ tendres]

I'm having a common problem with this pedal.  I have to turn my volume up all the way to hear it too!

Ive tried three different diodes, and got the best result out of a 1n270

Will using the correct diode increase the volume?

Also, it doesnt seem to matter which way round I put the 2n2222 its sounds the same.

Also I accidentally cut the red battery cable and the volume increased! but then reattaching it caused the volume to cut out.  I have the negative battery lead attached to the input jack ring.

help

[tiges_ tendres]

Never mind!

I fixed it!

Check and double check your work.  Best advice ever.

I forget to run from the input cap to the base of the transistor.

:oops: