Is it possible to mod the Boss Katana 50 (version I or II) to add a send and return between the pre-amp and the power amp stage? I know the 100W version has an external effects loop, but I'm a bedroom player and I have no use for a 100W amp. However, I'd like to be able to put my looper pedal after the pre-amp and built-in effects.
To paraphrase this post: https://www.vguitarforums.com/smf/index.php?topic=22478.msg200736#msg200736 Nothing is impossible, but it's cheaper to buy an amp with actual effects loop.
If you have access to another amp and speaker you can use take signal for the looper out of the headphone out, as this article suggests: https://www.zombieguitar.com/using-a-looper-with-the-boss-katana-50/