Jon here... My wife got me a Boss Katana Mini so I can play at home with the kids. I was quite surprised by the quality of tones I was able to get out of it, both for clean, break-up, and some high gain riffage. Probably the best bang for your buck in a small battery powered practice amp (and no we don't sell them, so I'm not just shilling). It could also get quite loud considering it's size. However, not loud enough to jam with a drummer or anything like that. Recognizing that smaller speakers are generally not very efficient ( read our other blog on speaker efficiency for more on that), I wondered just how loud it could go with the right speaker. So, we opened it up to add an external speaker jack, and the result was fantastic.
I'm not sure the video qualifies as a tutorial since the explanation in the video leaves much to be desired, so I'll break it down further here... Disconnect the wires running from the amp to the speaker and connect them from the amp to the common lugs on a switching jack. Then run wires from the other side of the jack to the internal speaker. Voila! Just remember, the tip is positive (+) and the sleeve is negative (-).
The stock speaker is 4 ohms, so be sure to use a speaker (or cab) that is at least 4 ohms. It is a solid state amp, so you'll do no damage going above that, you'll just lose power. We used an Eminence Governor (8 ohms) in the video, but you can use whatever speaker suits your fancy.
The result will give you some massive tones that you can certainly mic up to record or play live. It may even be loud enough to keep up with a drummer, depending on the volume of their playing.
Just be aware, it voids your warranty so don't screw it up. ;)
Mod safe, and mod awesome!