MXR M-103 Blue Box

[carboncomp]

Looking for a schematic for the MXR M-103 Blue Box (the version with the two LM741CN)

[agoldoor]

Wow, that's SO weird, I just came on to do the same search, and saw your post. Please, if anyone has one, please post it!

[Dr Tony Balls]

I dont think its any different it just used two single op amps instead of one dual. If you look at it the parts count is the same for resistors, caps, and diodes, and all of the resistor values match. Its hard to see the values on the caps, but you can clearly see two pairs of matching tantalums, which would account for the 1uf and 10uf caps. I think its the same.

[carboncomp]

I dug out these layouts I got from Brook over at Pigeon FX, if they are any help to you?

(He did me a PCB to help restore my battered unit, but cant find the schematic to hook the inputs and pots back up!! )

[Dr Tony Balls]

You could peep at this to verify it. Seems to be the case based on my quick exam.

[carboncomp]

Thanks guys,

So based on the later schematics, dose this look right for the connection for the the MXR M-103?

[peps1]

Thanks guys,

So based on the later schematics, dose this look right for the connection for the the MXR M-103?

Almost!



Back home now for a few days, so pop round if you need any help!

[mariogilberto]

What about potes, blend and vol
And transistors and diodes??
Can you help??

[creachureofthenight]

Can anyone here help me with modding my mxr blue box? I'm trying to make it a little less glitchy by adding a 1 or 2 octave toggle switch. Can anyone help/provide pictures of how to do this?

[CheapPedalCollector]

Really old post, but those 2 tantalums are .47uf not 1uf.