Cheap 2ch subwoofer/bass shaker amplifier

Good for low power applications (I suggest staying below 50w), I use it for Dayton audio 50W shakers. Drives them very nicely. Also tested with the Hexibase 7th order band-pass 4in sub which also worked nicely. Due to the nature of the cheap amplifiers, ENSURE your speakers do NOT CLIP or produce DISTORTED SOUND. Amplifier connects to the SUB output of the AVR via a Y RCA cable or through the front 3.5mm AUX jacks.

Parts List

• 2 downloadable and printed case parts from Printables
• 1 TPA3116D2 Stereo Amplifier Board (1x)
• 2 RCA Audio Input Jacks (2x)
• 2 Speaker Terminal Blocks (2x)
• M3x4.2x6 Threaded Inserts, some
• 2 pairs of Terminal Connectors
• 1 XT60 power connector (search “XT60 male” on preferred supplier)

The entire build costs about €40

Assembly Instructions

1. Print and Prepare

• Print the two case parts from Printables using standard PETG or PLA.

2. XT60 Connector

• Solder 3 wires to the XT60. Grounds connects directly to the amplifier, while the positive lead will later route via the power switch.
• Glue the XT60 securely into its case opening.

3. Amplifier Board

• Place the TPA3116D2 amplifier board in its designated slot.
• Attach and tighten the potentiometer nuts on the outside front panel.
• Before screwing in, connect the audio input cable, solder in the audio input connector (RCA jack), speaker wires, ground to XT60 negative wire and positive to a wire which will go to the switch later

4. RCA Input and Terminals

• Solder the RCA jack and mount in its hole, this step will be fiddly so take your time and do it once!
• Mount the bottom two speaker terminals and solder speaker wires to them.
• Repeat previous steps for the second amplifier. Ensure boards do not touch, the case design should prevent this, but double check!

5. Switch and LED

• Install the pushbutton switch.
• Solder the XT60 positive wire to the switch common.
• Solder the two amplifier positive wires to the Normally Open (NO) terminal.
• (If using the switch’s LED:) Connect one LED pin to an accessible RCA ground, and the other to the NO terminal. To dim: add a 100k resistor in series (might be useful if you plan to use this in a dark room in front of the screen as the LED is very bright by default)

6. Threaded Inserts & Lid

• Using a soldering iron, press the M3x4.2x6 threaded inserts in the four lid holes.
• Attach the lid with four M3x8 screws.

7. Final Checklist

• Check all wiring and screw connections.
• Plug in a 12–24V supply, audio source, and speakers. Test activation with the switch and enjoy!

ENJOY YOUR NEW AMPLIFIER