9V Battery Tray Adapter for LR Baggs Para-DI (and others)

prusaprinters

<p>Some audio stomp boxes use a 9V battery tray that makes it tricky to adapt to wall power. The <a href="https://www.lrbaggs.com/preamps-di/para-di-acoustic-guitar-preamp/">LR Baggs Para Acoustic DI</a> uses the battery tray and doesn't have the typical 5.5mmx2.1mm power plug.</p> <p>I considered hacking in the power connector, but decided instead to 3D print an adapter with the same dimensions as the battery tray so I can use the pedal with wall power and without modifying the pedal.</p> <p>Source files included for FreeCad (0.16).</p> <h3>Post-Printing</h3> <p><strong>Assembly notes</strong></p> <div><ul><li> the little wedge on the bottom keeps the tray from sliding out.. this is somewhat optional (mine was a pretty snug fit without it) and you might have to tweak your printer parameters a bit to get this to work. Mind the direction of the wedge, the point is to keep the tray*in*. <p>The power jack is a Radio Shack 2741563 but any similar 5.5 x 2.1mm coaxial power jack should work (7/16" hole). Good luck finding a Radio Shack, nowadays.</p> <p>I had to enlarge the wire holes slightly. Light gauge solid wire is probably easiest to work with (20 or 22 ga). I used stranded wire, but pre-soldered it.</p> <p>Be aware of the polarity of your device! Most 9V stomp boxes use a center-negative power connector (Thanks, Boss/Roland). Getting the polarity wrong could toast your precious pedal. Use a volt-meter and check the polarity while connected to the power adapter<em>before</em> powering up the pedal!</p> <p class="detail-caption"><strong>The high part of the wedge is near the little handle/front of the tray</strong></p> <p class="detail-image"><img src="https://cdn.thingiverse.com/assets/c3/80/d5/45/ac/9V-adapter-vs-battery.JPG"/></p> <p class="detail-caption"><strong>Soldering required. Note: negative on the left, positive on the right terminal in this pic.</strong></p> <p class="detail-image"><img src="https://cdn.thingiverse.com/assets/7b/83/48/f5/26/screw-terminal55x21-jack.jpg"/></p> <p class="detail-caption"><strong>If you're soldering-challenged then you might redesign the part to work with one of these screw-terminal adapters.</strong></p> How I Designed This =================== <p><strong>Design Notes</strong></p> <div><ul><li> Measured the existing battery tray and power connector with digital calipers <p>Designed in FreeCAD (Why doesn't Thingiverse list FreeCAD in their standard list of programs?)</p> <p>Went through the print/test/tweak-design cycle a few times until it was right</p> </li></ul></div></li></ul></div> Category: Electronics