3.5mm to xlr adaptor – does it make it balanced?

the specs for your shure mic say it uses a TRS connector so it is probably a balanced source. Adapting always degrades the signal a bit and introduces noise. Keep your cable short. Read http://www.portlandmusiccompany.com/balanced_unbalanced.php

http://www.portlandmusiccompany.com/balanced_unbalanced.php

An unbalanced to balanced adapter does not make the whole thing balanced. It is, as you say, just letting you connect one type of plug to another. As to the mic, which is mono, a tip ring and sleeve jack plug does not nescesarily mean it is balanced. More likely to make it compatable with most camcorder external mic sockets.

The tip ring and sleeve on this mic is wired with tip and ring as signal and sleeve is the usual ground – so the mic is unbalanced and Shure don;t make it easy to find this out, but the info is on their web site. This means that tip/ring will go to pin 2 of the XLR, sleeve is connected to pin 1 and 3. This also means any 3 circuit 1-1, 2-2, 3-3 ready made cable won't work, because it shorts out the audio! However, if you make up your own cable, it will work fine unbalanced.

The reality of unbalancing a balanced input is very rarely as problematic as people suggest. You lose a bit of sensitivity and lose the differential benefits in interference prone environments – but remember a foot of cable is really very unlikely to be an interference problem. If I was going to always use the mic with a camera needing an XLR connector – I'd just chop off the 3.5mm and solder on an XLR!

But what happens what if I want to connect a plug in power mic such as Rode video micro to a camcorder with cor plugs and 48 volts. How can I make a diy adapter?

Well – yes you can, if you understand electronics and can build the circuit to convert one power type to another. A camera with +5V hot power superimposed on the audio, or as a dedicated supply voltage as a separate core is much more difficult convert to 48V balanced phantom power, but circuits exist to up the voltage and carry out the balancing. In practical terms, if you are no good with a soldering iron – just buy the appropriate mic type for your camera.

I am good at soldering, but i have seen so many variations that i can not decide which one to follow. Any advice on that?

I lean to the simplest solution which is 2 x 2k resistors on hot pins that lead to a 5,2v zener and a 47uf capacitor between pin 1 and 2-3

What do you think about that?
Regards