Shelly13 - Part1

1 minute read

After playing MobFobAmp for a while, I wanted to take another step in the evolution towards a really good portable instrument combo. With this design I’m trying to address the shortcomings of the previous prototypes:

  • Power output could be higher
  • More volume in the low lows would be nice
  • Folding mechanism a bit fiddly.
  • I’d like a one-step unfold, preferably one-handed operation possible
  • Mechanical stability and robustness could be improved
  • Sensitive components mounted on the outside requiring to be handled with care

A first design

Taking the above points into account, I figured out that I had to compromise foldability a bit to get all the sensitive components including the speaker chassis to the inside of the cabinet. A ball-shaped design would be ideal for best low frequency / size ratio, but I didn’t know how to manufacture such a design - so I went with a cylindrical approach. I’d like the speaker to “pop up” so it would be protected from mechanical damage when folded. So my first idea looks like this: Shelly13 scetch

Project constraints

I cannot manufacture the cylinders myself so I’d have to contact a drums manufacturer to send some unfinished custom-size Tom-toms over to me. Even if I get those, I’ll have to cut on a curved surface which I never did before, and I’d require some 3D printing / routing to craft an adaptor plate between speaker and cylinder… Or will I just have the speaker mounted on the top/bottom? Plus, I’d have to think about how to include a more powerful amplifier into my design - there are some ideas like this Pioneer car amp or the specialized Hi-Fi amp from DIY Class D but they have very different and maybe harsh requirements on power supply…


You see, many open items to think about. I’ll let this sink in for some time before continuing work on this project.