There is line input on this machine and I have been told by Apple that it needs to have a self powered microphone to work. I have tried the Griffin USB adapter to no avail and my hardware test cd rules out any hardware issues, says Apple support. Please do not speculate here. I am looking for someone who has actually been through this. My G4 tower has the double mirrored dvd doors in front even though only one of them function. The other is a dummy or extra bay. It runs with the dual 1.42GHz processors.
Thanks: Darrel

I am not sure I understand what you are asking. A line input requires a line-level signal which will be output from a microphone pre-amp. A microphone level signal is much lower and not usable by any means in a line level input.

Can you clarify your question?

As for the Griffin adapter, I am assuming you have described the problem to their tech support and they were not helpful either. What were your connections with the Griffin adapter?

Carvel