About 10 years ago I built a battery powered small amp for front porch/etc. playing. The amp circuitry is on a removable bent aluminum panel, and I made several variations. (Including a decent start on a 1watt mini tube, that I really should go back to completing!). Speaker is a 6 inch Jenson. It sounds okay on guitar, but is exceptional for low volume 5 string bass. It’s also been my test platform.