Curiosity inspired me to take apart my Z-2300 subwoofer. The grill pried off without much difficulty, and I was even able to reassemble it with minimal cosmetic damage.

WARNING: Perform this disassembly with extreme caution! The enclosure contains a 120V AC transformer. With the Z-2300 turned on, unplug the power cord and wait for the power LED to fade. This will drain the capacitors and minimize the possibility of shock.

Various facts discovered:

• Subwoofer uses an 8 screw mounting pattern
• Subwoofer impedance measured at DC: Single voice coil, 6.5 ohms (8 ohms as per specs)
  • The amplifier had no problem driving an external 4 ohm subwoofer in a separate enclosure.
• Subwoofer construction: Corrugated paper and foam surround.
  • Logitech Model #: W200OF120-02F
    OEM: Tang Band W8-670Q
• The Z-2300 uses a JRC4565 operational amplifier for pre-amplification and an unidentified chip amp for output amplification
• EDIT: Satellites and subwoofer use TDA7296 and/or TDA7295 Class AB amplifier IC’s (identified by judeh101)

Potential modifications:

• As others have done, the enclosure could use some sound dampening material.
• Replacing the subwoofer with a better made 8″ woofer (polypropylene cone and rubber surrounds) would probably improve sound quality. The amp can handle 4 ohms (based on my limited testing), which means output might even be stronger with such a woofer. However, the amplifier’s 150Hz crossover is fairly high and should ideally be reduced to below 100Hz. If I get around to replacing the sub, I’ll figure out the amplifier circuitry and post that modification.