Q: Could you please tell me if the second-generation iPod touch is compatabile with Logitech mm50 speakers?
A: Unfortunately, the answer is not a simple one, as there have apparently been two or three different models of the mm50 released in the past three years. While just about any iPod speakers will work fine with the iPod touch for actually playing back audio, many of the older speakers will not actually charge the iPod touch (nor the 4G iPod nano or iPhone 3G). The problem is that with most of this year’s iPod models (and the iPhone 3G), charging via the older 12V FireWire circuit is no longer supported.
Early mm50 models, which were designed to charge the third-generation iPod will definitely not charge the iPod touch, since ironically the 3G iPod only charged via the 12V FireWire and not the 5V USB circuit. However, you should still be able to listen to your music through these speakers until the battery goes dead. Further, there have been some reports that if you have a Dock Connector port on the back of your mm50 speakers, you can connect a USB cable and USB power adapter for charging through this port, but this is not recommended as it will likely cause sound quality problems.
Newer mm50 models without the Dock Connector port may or may not work for direct charging of the iPod touch, depending on what charging standard they use. Reports from various users seem to indicate that there are actually two of these models of mm50 out there, with one using 12V FireWire charging, and the other using 5V USB charging. Unfortunately, there would appear to be no way to distinguish between these models other than actually testing them, although the 5V USB mm50 model does appear to be far less common.
The bottom line is that regardless of which model of mm50 speakers you have, playback through the speakers with your iPod touch should work just fine. However, the majority of mm50 models out there will not charge the iPod touch, so you will need to connect it to another power source to recharge it after listening to it for a while.