This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Tuesday, May 12, 2015

Maxon OD808

Maxon released the OD808 in 1979 and it generates natural, mild overdrive tones and is similar to the TS808. Original units used MC1458P ICs, but I've listed JRC4558s as they're likely to be on hand for many of you. Also the original diodes were Panasonic MA150. I've listed 1N4148s as a replacement, but socket and experiment there. I've read of people using 1N60Ps or similar germanium diodes to give it an even more tube-like sound.


13 comments:

  1. I wonder the 1M resistor on the input??? Is it right???

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    1. It's a pulldown resistor that's there to help prevent switch popping if you're using a 3PDT footswitch. Pretty common mod for that. Just about every layout on this blog has it.

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  2. Hi, got question about 47uF between 10K and 4.7K resistors. Did you mean 47nf ?? And there's missing hole for 200nf

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    1. Yeah, that's a typo. Should be 47nF. Adding the missing hole.

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  3. Is there supposed to be a 5.6 zener diode from the original schematic?

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    1. That's present in Maxon's on/off LED wiring, but I've left that out of this layout. See the General Layouts Notes tab for offboard wiring diagram.

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  4. hi, the underside is not reversed

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  5. Hi, I noticed that the 51k resistor is connected to "Drive 1 & 2" but in the transfer image it is connected only to "Drive 1". In other words, "Drive 1 & 2" are connected while "Drive 3" is isolated from 1&2, but in the transfer image "Drive 1" is isolated from 2&3 and "Drive 2 & 3" are connected.

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  6. i built it. works perfect, transfer image "Drive 1" is isolated from 2&3 and "Drive 2 & 3" are connected - it's right.

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  7. How do I decrease the overdrive on this pedal? What I mean is, how to I increase the minimum overdrive? I use this pedal as a clean boost and I want to use a little less overdrive from the pedal.
    Can I reduce the overdrive by changing the overdrive control from 500K to 250K, and/or increase the 51K resistor?

    Please advise?
    J

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    1. Try reducing the 51k resistor value. That's limiting the lowest gain level. Lowering the pot value will just lower the max gain. Try 10k or even 4.7k. This will slightly lower the max gain as well, but probably not all that noticeably. (Especially since you're after a cleaner tone)

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  8. Hi... Is it layoout work...?

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  9. This comment has been removed by the author.

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