X2 capacitors in audio

[stevomaso]

I recently purchased a preamp kit that uses class X2 MKT capacitors for coupling stages in the signal path. As X2 capacitors are used in safety/suppression, are they really suitable for use as coupling capacitors. If they are then how would class X2 metalized paper capacitors perform as signal coupling capacitors.

[wintermute]

X2's are often polypropylene which is considered desirable for signal coupling, however MKT is polyester which is frowned upon in some circles. I'm not sure that I personally would be able to tell the difference (though I personally would only use polypropylene if they would fit just in case)....

I used X2 metalized paper (polypropylene) caps for the caps in my amps output network. If you are thinking of replacing them, have a look at element14 (formerly farnel) or rscomponents and look for polypropylene caps. You should be able to find something with the same pinout as an X2 cap (27mm I'm guessing).

edit: someone with better understanding of cap specifics, and able to make more sense of the datasheets may give a reason why X2's may or may not be suitable for coupling duty.

Tony.

[davidsrsb]

X2s are normal metallised plastic capacitors, which are specified to clear shorts safely, without burning,
There is nothing wrong with them for coupling except the lack of a fancy brand