how can I find the polarity out from my XLR

Others will tell you how to figure it out but after you do, a tip.

If you have to change polarity on the cable, do it at the source end. This is because the signal cables are often different from the return wires; you want both signal wires to be the same no matter what config you end up with.
If you have sealed cables send them to the manu and they will do it at a nominal charge and they will still be factory.

I can only say that it is unlikely that the manufacturer went through the trouble of having polarity labels made, only to have it be wrong. So you can be 99.9999% sure that the polarities on each machine are as they say they are. You can check the polarity of your interconnect cable, by using an Ohm meter and verifying that pin 2 on one end is actually wired to pin 2 on the other end. The same for pin 3. If they are, then you have incorrect polarity on your system, and you have to match the polarity. The way to match the polarities from one to another is by reversing the polarity of the leads in one XLR connector on one end of your balanced interconnect cable. This involves removing the barrel of the XLR connector and de-soldering the wires from pins 2 and 3, and re-soldering them in the reverse configuration. Leave pin 1 alone. If you can't do this, take the wire down to a good technician, and have him do it for you for a few dollars.

Try changing your speaker cable connections at the amp. Move the (+) to the (-) and vice versa.

If the sound improves substantially, then your XLR connections (or some other connection) are reversed polarity.

> Ivany
hi,
my only problem is that I have to give to my 'DIY cableman' the right polarity out of my CD player to match with the polarity 'In' in my preamp
I know the polarity In of my Preamp (1,2,3 pin are ok it's an US Cello Encore)
but I've a doubt about (+) pin out of my CDP ( I'm not sure (+) is out of pin 3 it's an european Sony player)

Disregard my post, because I mis-read your question. I thought that it said your polarity was different from the CD player to the preamp. Sorry.