Project files: LM3875 Gainclone and PSU

What is it?
These are the board files for the LM3875-based Gainclone amp and matching PSU described here.

How big are the boards?
Both boards measure 3.925″x1.5″ (app. 10 x 3.8cm)

What is the status of the boards?
The boards are both in version 1.2. I have built version 1.1 of both and corrected a couple of minor mistakes in the layout afterwards.

Does it use any special/expensive/hard-to-find parts?
Not really. The layout is quite tight though, so remember to check the fit/dimensions of your components before ordering.

Anything else I need to know?

  • Because I couldn’t get the ICs closer to the edge of the board I recommend that you use the LM3875TF (the isolated version) to be able to mount it flush against the heat sink.
  • The big caps on the amp board are supposed to be 18mm in diameter, but the two middle ones are so close together that 16mm caps are preferred instead.

Download design files here

Related information:
Note: Always read the “intro post” for additional important information about my designs.

You can find additional information about the LM3875 gainclone in the LM3875 build guide over at



3 Responses to Project files: LM3875 Gainclone and PSU

  1. Pingback: Project files: New gainclones | theslowdiyer

  2. Pingback: A Smaller Gainclone… | theslowdiyer

  3. KamalT says:

    Hello…Can you please help confirm the BOM for this amp…I am using the single board for 2 channel version…

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