Newsgroups: rec.audio.tech Subject: Re: wiring plug-in power mic to non-powered mic device References: <[email protected]> [email protected] writes: > Are there any technical reasons why I couldn't wire a plug-in power mic > to non-powered mic device (ie like my phone)? If you plug a microphone which need a poer to adevice which does not provide it, you will get no sound of the microphone. > The idea was to make a box with two 1/8 inch jacks. Plug mic into 1, I > get the PC, plug mic into the other, I get the phone. This way I can > switch off between "real" phone and internet phone withouth mucking > about with two headsets. > > I have an Andrea headset mic, which needs power from the pc to operate > (so I have pwr, signal, and ground to work with). The first jack would > go to my PC (wired straight-through), and the other jack would go to my > phone. This phone jack would have signal and ground connected to the > phone, but it would also have a connection to the power (from the PC). > I'm not sure if I need to tie the grounds together or not, or if I > would get some kind of "ground loop" problem. You will get into groundloop problem with this kind of configuration. And also risk of damaging your headset, telephone and soundcard! Anythign you connect from the telephone line to a PC needs to be isolated electrically from each other. If you feed the power connection directly like you described, you will not have isolation which will lead to problems which cause the system at best not work correct and and worst equipment damages and/or electrical safety hazard. > Can someone tell me if they thing this is going to work or not, and why? What you re planning to does not work. explaing all the details of the telephone equipment interconnection is quite much in one news message, but you will find information on telephones and telephone line interfacing at http://www.hut.fi/Misc/Electronics/circuits/teleinterface.html Prepare to spend at least few hours with that document... -- Tomi Engdahl (http://www.iki.fi/then/) Take a look at my electronics web links and documents at http://www.epanorama.net/
