I'm actually not sure it's the ECM-55. It's one of the models (44, 55, 66, 77), but they don't say the model number on them, and they all look very similar. They're hardwired to an 1/8" connector, but when I plug it into my mic-in jack on my MD, I hardly get anything when everything's at full, and only out of the left channel. I guess the plug-in power isn't enough for it? I'm going to build the battery box first and see if that amplifies it more first. Then I'll work on wiring two together to make a stereo pair. I'm just going to do trial and error, and I'll try to post my results.