Fig. 19

Part 4: Electronics and Finishing Touches

Step 23. In the 24"x17" rear panel, drill a hole just large enough for the speaker jack.

Step 24. Before you attach the jack, measure out a 3' length of wire. Solder the positive to the tip and the negative to the sleeve (Fig. 19). Now mount the jack. If you position it above the plane of the speaker board, also drill a 1/4" hole in the board so the speaker wires can snake up through it.

Note: If soldering is a challenge, read “Soldering 101: A Step-by-Step Guide” in the November 2014 issue of Premier Guitar, which can be found at

Step 25. Now we need to give the motor power. Cut another length of wire, keeping in mind this will need to run from the top of the enclosure where the motor is all the way down to where the power will be. I cut mine to 5 1/2', because I like to have a lot of wiggle room to work with. Strip the wires and solder them to the motor. Use heat shrink or electrical tape to prevent the positive and negative wires from making an unwanted connection. Then, using your staple gun, staple the wire taut all the way to the edge of the roof so your baffle doesn’t hit it when it spins (Fig. 20).

Fig. 20

Step 26. Once you finish stapling, it’s time to install the IEC power jack. Measure its dimensions, then cut a matching hole in the rear panel using your jigsaw. After checking that it fits flush onto the door, mount it to the rear panel.

Step 27. To wire the IEC jack, cut off the receptacle side of your 3' or 6' extension cord, and then separate the two wires and strip them. AC current has no polarity, so it doesn’t matter which wire you solder to which terminal, as long as it’s the upper two terminals, as shown in Fig. 21. Solder the wires to the terminals.

Fig. 21

Step 28. To cut the grille cloth, measure the length and width of your windows. Take note of that measurement, and then add an inch or so to both numbers, since you want a bit of overhang. Cut it to size with a utility knife—one piece for each wall, four in total (Fig. 22).

Fig. 22

Step 29. Pull the cloth taut over each window and staple the corners (Fig. 23), making sure the fabric is tight.

Fig. 23

Step 30. Slip the baffle off the motor shaft and put it aside. Place the roof on top of the box and staple the dangling motor wires to the nearest side wall. Make sure they’re far out of the way of the rotor baffle, and then push the baffle back onto the motor shaft.

Step 31. Position the rear panel and screw it to the sides. Screw the four 3-leg metal corners around the top, as in Fig. 24. These 3-leg corners secure the top to the cabinet walls. Now screw the four lipped metal corners to the bottom of the cabinet, and then add rubber amp feet (optional).

Fig. 24

Step 32. Now it’s time to hook up your electronics, following the easy wiring diagram in Fig. 25. The red line represents the positive and the black line represents the negative wires of both the motor and power supply. Once you’ve wired everything up, you can organize the power supply and wires any way you like inside the cab—just keep everything clear of the rotating baffle.

Fig. 25

Step 33. If your PWM controller came with a speed control pot, test it to make sure it works, drill a hole in the front of the cabinet, push the pot through, and mount it.

Step 34. Now find your handle, center it, and screw it into place. Make sure you bend it upwards slightly before installing it, so your hand will have room to grab it.

Just like that, you have now finished your very own rotary speaker cabinet! Plug it into your favorite amp’s speaker output, and then plug in the IEC power cable. Turn on the unit, set the speed where you like it, and fire away!

Author Yoel Kreisler welcomes questions or feedback about this project. You can reach him at