Shelly13 - Part1

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:

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…

Conclusion

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

CNC job setup

Job preparation and quick demo

Measure Inrush current

of an audio amplifier

My CNC vibrates

From investigation to problem solution

Image to Path

From Pixel to Vector graphics

Symptoms of insufficient spindle power

My Endmill ‘screams’

Beginner CNC issue: Speeds/Feeds

CNC Part5 - Macros

Automatic Z-referencing, Tool length, Tool changes

CNC Part 4.1 - Config

EdingCNC Settings & Variables

CNC Part4 - Setup

Software/Hardware setup & kinematics

CNC Part3 - Build

Assembling Sorotec’s Basicline 0607

Switch box setup

CNC Part1 - Portal milling machine

Entry-point and questions

Inrush Current Limiter - Part2

Circuit & Application examples

USB Power Delivery

USB-PD power supply explained

Metabo / Cordless Alliance Systems

Can I use a Metabo/CAS battery for my system?

How to set protective voltage & current limits

Inrush Current Limiter - Part1

Current inrush limiters explained

Transient Voltage Suppressors

Electronics knowledge: TVS diodes

Power supervisor MAX1756x on capacitive load

Or how to kill your circuits

Convert videos with VLC player

How to properly talk to VideoLan’s VLC player

My Printed Circuit Boards arrived!

Prototype build, issues, improvement ideas for Revision2

How To: First steps with FreeCAD

How to create better PCB designs

Professionalizing circuits for AnywhereAmps

Preamp design considerations

AnywhereAmp Alpha’s simple single-supply preamp

Shelly13 - Part2

Design, folding, stability, amplifiers

Shelly13 - Part1

Evolving the mobile, foldable instrument combo

Markdown to PDF

Export the instructions from Markdown to PDF! but how?

Jekyll: images

Why some images display OK locally but won’t on Github

How to make ToC sticky