As iPod touch enthusiast Marian continues working on his pre-amped dock-connector Mic for the iPod touch, my Amazon Marketplace MicroMemo (i.e. clearance and cheap) showed up this morning. I loaded the latest Voice Notes onto my iPod touch, hooked in the MicroMemo and gave it a try.
Like most recorders, the MicroMemo provides two settings: Mic and Line. I found that if I shouted into the attached microphone on the Mic setting, I could just about be barely heard on the recording. Using line-in from my Macintosh was far more successful, albeit with line distortion and clipping.
I've put my test samples over at my ftp site. The LineInput is 15 seconds of music straight from my mac, over the line connector, using the Line settings. The two voice samples are Line and Mic. The Line sample is completely inaudible. There actually is a signal on the Microphone version but it's very very low--be careful not to blast out your eardrums after adjusting your playback to hear it.
I suspect if I lower the volume from my Mac, the distortion and clipping will go away but although I tried hooking my microphone through a radio-shack amplifier, the Mic recording remained very limited.
I'm not sure why the iPod touch audio-in signal would vary all that much from, say, the iPod video. I tested the same MicroMemo with a 5th Generation iPod and it worked beautifully, with clear levels.