A few weeks ago I got the urge to build some kind of portable stereo that would serve equally well on the workbench and as a ghetto blaster. I bounced ideas between paper sketches and simple 3D models, shopped around for potential parts, and came up with a design that could be started with what I had on-hand, plus speakers and batteries.
Eventually a good tripath or class D amp would be ideal, but I already have a small car amp to get started. At least a couple hours of use by either amp from a single charge was the goal, so I looked into the small 12V SLA batteries used in UPSes. Two were modeled in Tinkercad, the UB1250 (5Ah) and UB1280 (8Ah). Since a decent amp would require 24V I opted for 2 of the smaller UB1250.
The box would be built from a piece of 3/4” teak ply, roughly 11” x 44”, and I decided to keep it simple by minimizing the number of cuts. First cut off the 2 ends, rip the remaining length into top+bottom & front+back, cut each in half, and finally trim the ends to match. Combined with dimensions of major components (batteries, speakers, amp) this determined the enclosure dimensions. A final 3D model was used to verify everything should fit.
The next post will cover initial construction of the prototype.