Pin 2 / Pin 3 Hot ?

[Winetree]

The Harrison Mr-3 multi track snakes from the patch bay are wired pin 3 hot. So the console is pin 3 hot +
So I wired the radar recorder's D-25 connectors plus to pin 3 hot + on the XLR patch bay. So everything is pin 3 hot + from the console back and forth to the radar recorder. OK
So what happens when when I use  an external pre or outboard with pin 2 hot +?
Are those tracks out of phase?
Do I need to wire reverse polarity multi? Or does it make a difference?

 

[Bo Deadly]

Right, the signal would simply be inverted which should have zero effect on the sound.

But I don't understand what you mean about the DB25. So you just wired it normally then? If you swapped 2/3 then the phase would be corrected.

 

[Brian Roth]

Before JR or others "jump in", the correct terminology is "polarity" instead of "phase".  But, whatever....

One possible problem source would be external mic preamps.  You need to somehow "fix" those source signals since they could have an interaction with other signals in the chain. 

Balanced in/out outboards shouldn't cause any problems since the absolute in/out polarity through the gizmos should be intact.

Bri

 

[pucho812]

If it is a balanced I/O it wouldn’t matter. The reason is yes the polarity flips on the way in but also flips on the way out. Where it will cause issues is unbalanced signals.

 

[Brian Roth]

Here's how you design a system....flip the spinner!

http://brianroth.com/library/AES_Pin2-3.jpg

lol

Bri

 

[JohnRoberts]

The Harrison Mr-3 multi track snakes from the patch bay are wired pin 3 hot. So the console is pin 3 hot +
So I wired the radar recorder's D-25 connectors plus to pin 3 hot + on the XLR patch bay. So everything is pin 3 hot + from the console back and forth to the radar recorder. OK
So what happens when when I use  an external pre or outboard with pin 2 hot +?
Are those tracks out of phase?
Do I need to wire reverse polarity multi? Or does it make a difference?

Pin2/3 hot is meaningless for balanced in/balanced out audio paths since the output will maintain the same polarity as the inputs.

where which pin is hot matters is for products with mixed balanced and unbalanced (single legged) audio inputs, or outputs.. Large consoles can often involve single legged and balanced i/o

If an external preamp is pin 2 hot, actually correct, with balanced output it should not be a problem.

Absolute polarity is not very audible (if at all for most signals).

About the only situation I would advise concern about is if using multiple microphones on a single sound source (like maybe a drum kit) with mixed pin 2 or pin 3 hot audio stems .  For that case you could get significant sound cancellation for similar signals. This "could" be most noticeable for low frequency sounds due to longer wavelengths. HF would generally have different enough arrival times to not cancel completely.

JR 

 

[pucho812]

at an old studio I worked at, we had some mics(sm57's and a few others) that were pin 3 hot while the studio was pin 2 hot.  Their solution was to label the mic vs change the xlr to pin 2 hot.  We then would use a xlr wired pin 3  hot on one end to pin 2 hot on the other.  I offered to rewire the mics but that would mess up their mojo.  :

 

[moamps]

"Balanced output" doesn't mean always that the signal in it is symmetrical,  so I would rewire the patchbay or use special cables  with pins 2 and 3 swapped for inserting an outboard into console and converter.

 

[JohnRoberts]

at an old studio I worked at, we had some mics(sm57's and a few others) that were pin 3 hot while the studio was pin 2 hot.  Their solution was to label the mic vs change the xlr to pin 2 hot.  We then would use a xlr wired pin 3  hot on one end to pin 2 hot on the other.  I offered to rewire the mics but that would mess up their mojo.  :

come on guys... unless the mics are 2-wire it doesn't matter... while you might not want to mix pin2 and pin 3 hot mics on the same drum kit.  :

JR

 

[JohnRoberts]

"Balanced output" doesn't mean always that the signal in it is symmetrical,  so I would rewire the patchbay or use special cables  with pins 2 and 3 swapped for inserting an outboard into console and converter.

It can be one-legged impedance balanced and still work, as long as it feeds a differential receiver getting it's input from both pin 2 and pin 3.  More an issue for the receiver than output.

Back in the 80's I actually experienced a problem with an older peavey (pin 3 hot) mixer that ignored pin 2... (IIRC it was a TRS insert that ignored the ring and just grabbed the tip signal. Not my design but I had to fix it. )  :-[  That did not work at all....

JR

 

[Whoops]

The Harrison Mr-3 multi track snakes from the patch bay are wired pin 3 hot. So the console is pin 3 hot +
So I wired the radar recorder's D-25 connectors plus to pin 3 hot + on the XLR patch bay. So everything is pin 3 hot + from the console back and forth to the radar recorder. OK
So what happens when when I use  an external pre or outboard with pin 2 hot +?
Are those tracks out of phase?
Do I need to wire reverse polarity multi? Or does it make a difference?

I would wire everything for Pin2 Hot,
it's the standard, it's more convenient,  you will have less thinking to do when mixing different types of gear with your system