How to go from RCA to XLR?


I've got an Aragon Stage One processor with RCA outputs and two Aragon Palladium 1K monoblocks with XLR inputs. I know there are a lot of RCA-XLR cables available, but a fabricator told me you have to know which XLR pins are "hot" and these have to match the amps' input circuitry or you will damage the amp.
So how do you know which pins to make hot when you order the cables? When you buy these cables "off the shelf" are you just hoping you get lucky and they match up with your equipment?
Thanks
noslop
Got some really bad news from Aragon tech support. Changing the XLR to XLR cable to an RCA to XLR cable, will cause the amp to run at only half power. Said half the input signal is grounded out so the amp, so the amp only puts out half power. Great.
Sounds like you need a single ended to balanced transformer like the Jensen model.
With designs that I am familiar with, feeding a balanced differential amplifier input with a single-ended signal will only mean that you have to turn the volume control on the preamp up a bit higher, by 6 db. It will not affect the maximum power output of the amp, only the volume control setting on the preamp that is required to reach that maximum output.

I suspect that the person you spoke to at Aragon doesn't know what he is talking about. Or else their design is very unusual in some respect.

A transformer such as Rwwear suggests will get you back most of the 6db, if that matters, but a quality transformer is likely to cost significant $, and even a good one may still have subtle sonic effects.

Regards,
-- Al
Noslop, the news you got is erroneous! If one of the phases is not present, the gain of the amp may be reduced by 6 db, but there will be no loss in power! Whoever told you that really has no idea how this stuff works.
Yes, I suppose any circuitry added will have a sonic signature but the Jensen transformers are the same one's Audio Research and Rowland use to make their products balanced. They claim the sound is better than truly balanced but I don't know. It's certainly much cheaper at around 200.00.
Atmasphere, isn't losing 6db of gain the same as losing half the output of the amp or more?