Attenuation required to connect DIY modules to external gear?

[fredrik]

This post, and the posts linking to it, discuss some options:

Which Final Output module?

Having been drawn into this rabbit hole I’ve bought a few eurorack modules to build. However I’ve no idea which kind of module I’ll need to use as a final output - be it to headphones, powered computer speakers or direct to my Mac. If anyone can point me at suitable eurorack DIY modules for this purpose I’d appreciate it.