Netgear WNR3500L Performance with DD-WRT

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I’ve been running DD-WRT on a trusty Linksys WRT54G v2.0 since 2006. Back then, DD-WRT hadn’t achieved the dominant position it holds today, but beta release by beta release it’s turned my router into a powerhouse that I can’t do without.

However, the famous WRT54G is starting to show its age: gigabit Ethernet is now standard, as is 802.11n, and 8MB of RAM is quite limiting. I upgraded the wired portion of my home network with a gigabit switch over four years ago, seeing that there were no decent (read: DD-WRT capable) gigabit routers when I needed the speed. Now that 802.11n is finally “official” according to the IEEE, I started shopping for a modern router. With a few simple requirements in mind—under $100, DD-WRT support, gigabit and 802.11n—I ended up with a shiny new Netgear WNR3500L:

Netgear WNR3500L

Netgear WNR3500L installed in my basement

This review takes a look at real-world 802.11n performance in my home using the Netgear WNR3500L loaded with DD-WRT v24, build 13527. Continue reading →

Logitech Z-2300 Remote Control Pod Disassembly

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Back in October I purchased a standalone Z-2300 subwoofer on eBay, knowing I could build a DIY remote control pod based on my working Z-2300 set. I disassembled my original remote and deciphered the pinout in a matter of hours. A board was sent off to BatchPCB the next day; two weeks later, I posted this video on YouTube:

Since then, I’ve received dozens of messages from fellow Z-2300 owners, all asking for more information.

Here’s the deal: It would be unethical of me to release the schematic and/or circuit board for public usage, and quite possibly a breach of Logitech’s intellectual property. There are no copyright, trademark, or patent markings on the Z-2300 speaker set or the control pod’s circuit board. However, a Logitech Product Team member at the Logitech message board writes:

“The wiring diagram is not a public document.“

This is understandable—no company publicly releases schematics for their products, and definitely does not allow for others to profit from the company’s products/services. As an engineer, I wholeheartedly respect that.

What is bothersome is Logitech’s backwards policy on Continue reading →

Logitech Z-2300 Subwoofer Disassembly

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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.
  • 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.