MXR Distortion Plus Clone with no distortion

[ramonki]

Hello Guys, this is my first Thread and i hope you can help me out...

This is my first stompbox, i bought the PCB from www.tonepad.com i wired it all but there is no distortion the Two Pots are most a volume pots, i have no problem with the signal or sound, using the 3DTP switch, i tried to replace both Diodes with the 4148 to increase the gain, but nothing... still clean sound,   i hope you guys can give me a hand on this!

The link is: http://www.tonepad.com/getFileInfo.asp?id=115 there you can find the PDF, diagram, and component list.

Thanks in advance!

Ramon

[jdub]

Hi, and welcome!  Your best bet is to start here http://www.diystompboxes.com/smfforum/index.php?topic=29816.0; following these steps will provide the helpful folks here with the info needed to zero in on the problem.  I would also suggest going here  http://www.diystompboxes.com/wiki/index.php?title=Debugging and following those steps, too.  Have you tried using the search function on this site as well?  This is a common project and there are numerous threads about it. The build .pdf at GGG (http://www.generalguitargadgets.com/pdf/ggg_dist_instruct.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a)
may also be useful since it has voltages for the IC for comparison.  After following the steps, post back with the info and people will be glad to help. Good luck!

[Electron Tornado]

The Dist + is a good, easy pedal for a first time builder. Having it not work correctly is frustrating, but look at it like this - it's an opportunity to learn something. And - we've all been there.

The Tonepad layout looks pretty clear. One thing you need to do (and it's often difficult for anyone) is to stop, and go through the layout part by part, and verify that you have the correct parts where they belong, and the wiring is correct. Attention to detail and checking your work has helped me find mistakes when I build.

If you can also post photos of both sides of the circuit board, that might help people here check it as well.

[pinkjimiphoton]

i just built a "tan" ross distortion, which is almost the same circuit. look at the couple of components connecting to the distortion control...
i had the same problem you describe, turned out to be a cold joint on the 1m resistor between pins 1 and 2 of the opamp...not looking at the schematic, so not definitive, but i bet your problem lies in that area...check for cold solder joints, or inadvertent bridges.

[pakrat]

+1 on the cold solder joints. I just built one of these for the 1000 competition and it didn't work either, only clean output. I retouched all solder joints and compared the pcb to the layout to make sure nothing was shorted..... turned out I had the input and output wires backwards  Hey, you never know......

[ramonki]

Thank you all for all your comments, i'm still stuck, i think i might try to simulate it on a protoboard so i can troubleshoot better! i will let you know what happened!

[asatbluesboy]

If you have no distortion but a quite big volume boost, my money's on the diodes. The MicroAmp has the same topology, but no back-to-back diodes to ground at the output.