Opening the subwoofer

To prevent any risk of electrocution, only open the subwoofer with the mains plug removed from the mains socket. For additional protection when working with any equipment that may be connected to the mains, always connect that equipment to a socket that is protected by a Residual Current Device, or connect that equipment’s plug to a portable RCD that plugs into the mains socket.

Fig. BD4

Top side of the green audio in jack socket and PCB

Fig. BD3

Panel removed, showing PSU (large black piece at bottom) and amplifier (top).

The only way to access the PSU is from the top after removing the speaker. Even then it is difficult.

Fig. BD2

Plastic back removed and showing mains relay PCB

Note the holes where the plastic back slots in. The “legs” from the plastic back are glued in place

Fig. BD1

Bottom of the subwoofer

Note the two grooves. Use a large flat blade screwdriver or similar in each groove to gently try pushing the

plastic back away. The back has “legs” which are glued into place. The back will need a little bit of forcing to

remove it. This usually means that the back will pull a thin piece of the board away when it comes off - see photos below

Fig. BD5

Bottom side of the green audio in jack socket and PCB

Fig. BD7: Speaker
Fig. BD6: Underside of grille

Removing the front cover

Remove the front cover in the same way that the back cover is removed above.

Do not pull the plastic away too far from the box. The bass control on the front has a short cable that goes through the box to a plug and socket on the amp PCB. The cable is not very long and here is a chance that you will pull the cable from the control joints.

If you want to remove the front cover completely, make a note of where the wires go on the control and unsolder them. The amplifier can be tested, and the left and right channels are not affected, but there will be no audio input to the subwoofer speaker amplifier part of the PCB - see how to work round this on the Subwoofer amplifier page.

Removing the speaker grille and speaker

The speaker grille is held in by four screws which are accessed from inside the box.

The wire from the speaker is soldered directly to the amplifier PCB. You will need to cut this wire before the speaker can be removed - see Removing the amplifier PCB on the Subwoofer amplifier page. Turn the box upside down and remove the four screws.

Turn the box upright.

The grille has four “legs” which fit into holes in the wooden top - the screws go into these legs

The legs may be a tight fit in the holes, so you may need to give a few taps from underneath the overhang of the grille at the front and back in order to release it.

The speaker is held in place by four screws. Remove these. The speaker may appear stuck. If so, use a flat bladed screwdriver to gently lever up the speaker edges near the screw holes. Do not use force, and do not bend the metal.

The speaker is heavy and has a strong magnet. Keep it away from anything that can be damaged by a magnetic field. Be careful not to damage the fragile speaker come.

When you replace the grille, make sure you replace the screws and do not lift the box just by the overhang of the grille. Although the grille might be a tight fit without the screws in, the weight of the speaker etc. can pull the box away from the grille if it is being carried.

Taking the box apart

Be careful how you handle the box. When you remove the front or back plastic, a bit of force may be needed because of the tight fit. Be careful not to suddenly tug the covers away from the box. Both the back and front have cables attached to the plastic and they are not very long.

As the cover starts to free itself, pull it away gently. When removing the back cover, be particularly careful of the mains cable that plugs into the relay board. This is short and pulling on it may damage the socket connection to the PCB.

Unplug this cable as soon as you can - see Fig. BD2.

Putting the box together.

Take just as much care when you put the box back together again.

Back of the box:

Before you put the panel back, make sure that all the plugs are tightly in place on the amplifier PCB.

On the relay board, connect the mains plug and 5v relay control plug that come from the amplifier PCB.

Make sure the audio in plug is connected to the audio in jack PCB on the back of the plastic case.

Arrange the cables as shown in Fig. BD2 so that they line up and come through the grooves in the back of the box, under the panel. Make sure none of the cables are trapped under the panel when replacing the panel. Do not pull the cables tight or you might pull the plug out of the socket.

When the panel is screwed in place, it should still be possible to gently push or pull the cables through the groove, although the 5v relay control and audio in cables may be a bit of a tight fit in the smaller groove.

Finally, line up the back cover to its approximate position then, holding the back cover, connect the incoming mains cable to the relay PCB.

Line the cover up so that the legs are level with the holes and give the cover a gentle tap at the top and bottom so that the legs start to go in. Give a few more taps so that the cover is back in place.

Front of the box

This is easier as there is no panel and only one cable.

Make sure you’ve put the foam strips back on the round plastic, if they’re not already there. Don’t pull the cover too much, or you could pull the cable from the bass control.

Line up the round plastic and push that through the hole.

Make sure the legs line up with the holes and tap the cover in place as above.


When taking the subwoofer box apart, you will find pieces of foam in different places. The foam helps to prevent unwanted vibration. If you do have to remove any, remember where it came from and put it back afterwards.

Removing the back