XLR Pin Vocabulary


Some manufacturers describe XLR pin polarity in a vocabulary of ground, non-inverting, and inverting. Others use a different vocabulary, ground, negative, positive. How does one translate into the other?
kusina
The pinouts are the same - it is just a matter of terminology. The correct terminology is inverting and noninverting. A true balanced connection means the cable is connected to a differential input. "positive" and "negative" come from the signs used for noninverting and inverting, respectively, in differential (balanced) amplifiers. Think about the schematic diagram of an op amp - an op amp doesn't have a positive input and a negative input, but rather an op amp has a noninverting input and an inverting input; the pins are labled with a '+' sign (noninverting) and a '-' sign (inverting). And the nomenclature comes due to the input stage, which is a a differential pair. So, in short ground = ground = shield; noninverting = positive; inverting = negative. Just keep in mind that the terms "positive" and "negative" when applied in this manner have nothing whatsoever to do with polarity.
One more note: Industry standard is pin 1 is ground, pin 2 is non-inverting (+) and pin 3 is inverting (-). Some manufacturers do not recognize the standard (we've even seen some using pin 3 as ground) but usually the only significance is that the signal might get inverted if only one of two products connected together is on the standard.
Atmasphere, both my preamp and amp have pin one as the ground. But pin 2 on the preamp is non-inverting and pin 3 inverting, while my amp has the reverse configuration (pin 2 -, pin 3 +). Since the amp is designed to be fully balanced, doesn't the mismatch compromise the sound? Should I have the interconnect cables re-wired, 2 to 3 and 3 to 2?