# Carmine Overdrive OC139 replacement



## Reno315 (Mar 16, 2020)

Are there any suggestions for OC139 replacement on the Carmine Overdrive build?

Would any "Rangemaster" NPN transistor from SmallBear be adequate? I see they have an OC140.

I appreciate the help and advice.


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## Chuck D. Bones (Mar 16, 2020)

I think a Rangemaster NPN from Small Bear will work as well in place of the OC139.  Don't get hung up on the part number.  It is common for SB to recommend or even provide the bias resistors that are matched to the germanium transistor they sell.  Use their resistors or follow their recommendations.  Which resistors should you replace?  That would be much easier to answer if the Build Docs were available.


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## Reno315 (Mar 16, 2020)

Solid, thank you for the information!
I did see where the transistors at Small Bear I was looking at did come with the bias resistors as you said. 
And you guessed my next question. ? Who do I reach out to for the build documents when they are not up?


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## Nostradoomus (Mar 16, 2020)

What do you need from them? There’s schematics floating around (and a vero layout) if that’s what you’re after.


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## Chuck D. Bones (Mar 16, 2020)

You can start a conversation with PedalPCB and ask nicely for the Build Docs.  Or you can wait patiently.  This is the risk you run when you buy a board and parts before the Build Docs are published.  Like Nostradoomus said, there are schematics on the 'net.


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## Reno315 (Mar 17, 2020)

Sounds good, thanks for pointing me in the right direction.


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## reubenreub (Mar 17, 2020)

I made a few boards of these as a way to learn eagle and used this schematic. Hope this helps!


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## Reno315 (Mar 17, 2020)

Stellar!!! This is what I was looking for. Thanks for the help!


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