Consequence of flipping pin 2 and pin 3 on XLR.
Nono
cold on pin 3.
I did take that into consideration when I wired it up some 20 years
ago.
But, in the course of time, as I kept bying new stuff etc., I did swap
cables between the different gear, and it just now struck me that I do
not remember if I checked this in any of those ocassions that I was
rewiring/re-installing the equipment.
Even though everything is working with minimal hum and noise, I'm
going to pull everything out to check if it's all wired correctly,
beacuse as sometimes you don't hear that something's wrong if you
don't know what to listen for, or if the sound you've accepted to be
okay should sound even better than what you've been accostumed to,
So, I'd really like to know what the consequence is of crossing the
hot and cold signal on the XLR pins 1 and 2 in this way.
Many thanks in advance,
Norman.
Scott Dorsey
If everything is actively or transformer balanced, the consequence is that
the signal is inverted, as if you had pressed the polarity or phase button
on the console for that device.
In the case of equipment that have an input and and output, like a
compressor or equalizer, they aren't pin 3 hot or pin 2 hot at all.
They either preserve the polarity of the signal or they don't... if
your input is pin 3 hot, the output will be too, and vice-versa.
Where you care about it is only with signal sources and destinations,
like microphones, amplifiers, and tape machines.
Where things get weird is when XLRs are used for unbalanced or
impedance-balanced inputs and outputs. If you have an unbalanced input
that listens only on pin 3 and an impedance-balanced output that only
drives pin 2, you won't get anything at all.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Peter Larsen
> I have one piece of equipment that has the hot signal on pin 2 and
> cold on pin 3.
Erm, that is the de facto standard, but you may want to verify compliance.
It is also a de facto standard that equipment shouldn't invert polarity, but
every now and then something does anyway.
> Norman
kind regards
Peter Larsen
Nono
Sorry, I knew I'd get confused. I meant it the other way around.
This (Roland R880 reverb) has the COLD on pin 2 and HOT on pin 3,
while my other gear do comply with the standard.
Thanks for pointing that out.
Norman.
Mark
> Nono wrote:
> > I have one piece of equipment that has the hot signal on pin 2 and
> > cold on pin 3.
>
>
pair for a stereo signal, in which case the polarity will be flipped
for one channel and not the other.. not a good thing..
i'd find it and mark it clearly or change it..
Mark
Nono
that in a balanced configuration it was not really necessary to invert
the cables for this one machine in the first place?
In that case I can change them all to one same standard no matter
wether the gear has the hot signal on pin 2 or 3, as long as they're
used balanced?
Scott Dorsey
>Sorry, I knew I'd get confused. I meant it the other way around.
>This (Roland R880 reverb) has the COLD on pin 2 and HOT on pin 3,
>while my other gear do comply with the standard.
>Thanks for pointing that out.
In fact, the R880 doesn't have hot or cold per se.... it preserves whatever
phase goes into it.
Although, pin 3 hot is the normal Ampex standard that about half the world
uses....
David Gravereaux
> Although, pin 3 hot is the normal Ampex standard that about half the world
> uses....
But not the AES standard, as of today. Also EIA Standard RS-297-A and
IEC 60352.
Don't get me wrong Scott, I agree with all your points. Especially
noting that when you have an outboard item with an input and output, it
really doesn't matter what convention is used as it'll come out polarity
preserved.
Absolute polarity is nice when the hook-up in your racks is such that's
it's easy to swap and clear to anyone opening the back to look.
My favorite rack hook-up are terminal blocks. EDAC on the back of the
rack fans out to the terminal block on the inside. Then each piece of
gear has a custom <connector> to spade lug. Want to switch polarity?..
swap the red and black on the terminal block, easy and obvious to anyone
that looks.
--
Peter Larsen
> Nono <n_henr...@hotmail.com> wrote:
>> Sorry, I knew I'd get confused. I meant it the other way around.
>> This (Roland R880 reverb) has the COLD on pin 2 and HOT on pin 3,
>> while my other gear do comply with the standard.
>> Thanks for pointing that out.
> In fact, the R880 doesn't have hot or cold per se.... it preserves
> whatever phase goes into it.
> Although, pin 3 hot is the normal Ampex standard that about half the
> world uses....
It was always interesting to have visiting US pa's in the 1970's, most used
pin 3 hot, and as a consequency many danish pa's did likewise to be
compatible with them, but for instance danish state radio used pin 2 hot. We
had a bit of a discussion in Copenhagen Sound Rental and ended up at pin 2
hot.
And then there is the red cap hot or black hat hot confusion in the
loudspeaker context, it combines well with the pin 2 or pin 3 issue ....
O;-)
> --scott
Kind regards
Peter Larsen
Mike Rivers
> Sorry, I knew I'd get confused. I meant it the other way around.
> This (Roland R880 reverb) has the COLD on pin 2 and HOT on pin 3,
> while my other gear do comply with the standard.
That WAS the standard until the Europeans started doing it the other way
and selling a lot of gear in the US. When Ampex was king, so was Pin 3
hot. That has a particular meaning with
a tape deck because "hot" is defined as the pin that goes positive when
a north-to-south transition passes the head in the normal direction of
tape motion.,
Mike Rivers
> But not the AES standard, as of today. Also EIA Standard RS-297-A and
> IEC 60352.
See the AES standard here:
http://i72.photobucket.com/albums/i197/OwwItHz/Pin2-3_Spinner.jpg
hank alrich
Funny! Except when it isn't.
--
ha
shut up and play your guitar
http://hankalrich.com/
http://www.cdbaby.com/cd/hsadharma
Soundhaspriority
"Nono" <n_henr...@hotmail.com> wrote in message
news:fa97abf4-94df-4874...@b33g2000yqc.googlegroups.com...
Nono,
What they're saying is that there really is no such thing as "hot"
versus "not hot" on a balanced connection. These are just terms to help the
user keep the polarity correct. The pins have symmetrical function.
Reversing the leads has the same effect as a "phase invert" switch, but
there is no more significance to it than that.
If you think that piece of equipment is flipping phase, then, yes, flip
the wires on either the input or the output, but NOT BOTH. If you don't
think it's flipping phase, then leave it alone, regardless of what the
connection diagram says.
Bob Morein
(310) 237-6511
Scott Dorsey
Right. And the problem is that the AES standard came too late to really
make a difference. We get manufacturers like Tascam, which sold the DA-30
DAT machine that was pin 2 hot but also sold the DA P-20 that was pin 3
hot.
The Sennheiser MD-441, if ordered with one option, came with a pin 2 hot XLR
but there was another option that gave you pin 3 hot, and a couple other
options with Tuchels....
When in doubt, it should be marked on the back with a Sharpie....
Nono
> Nono,
> What they're saying is that there really is no such thing as "hot"
> versus "not hot" on a balanced connection. These are just terms to help the
> user keep the polarity correct. The pins have symmetrical function.
> Reversing the leads has the same effect as a "phase invert" switch, but
> there is no more significance to it than that.
>
> If you think that piece of equipment is flipping phase, then, yes, flip
> the wires on either the input or the output, but NOT BOTH. If you don't
> think it's flipping phase, then leave it alone, regardless of what the
> connection diagram says.
>
> Bob Morein
> (310) 237-6511
Thanks guys,
I checked the cables and it appears that I did remember to connect
everything with the correct polarity after all.
I'll certainly try to consequently keep the connections in the right
way, but I understand that reversed leads by themselves shouldn't have
a negative effect on the sonic quality of the audio, which was my
concern.
Best regards,
Norman.
David Gravereaux
> When in doubt, it should be marked on the back with a Sharpie....
Agreed!
I had fun once with a brand new Drawmer DS201. Unbalanced ins and outs
on XLR. Manual said pin 2 hot... NOPE! After wiring up the rack to
an unbalanced Amek Angila (or was it a TAC Scorpion?), totally dead. I
had to open the damn thing to find it was really pin 3 hot.
--
Mark
>
> Thanks guys,
> I checked the cables and it appears that I did remember to connect
> everything with the correct polarity after all.
> I'll certainly try to consequently keep the connections in the right
> way, but I understand that reversed leads by themselves shouldn't have
> a negative effect on the sonic quality of the audio, which was my
> concern.
>
> Best regards,
> Norman.
like i said before..., if you accidentally flip polarity of only one
channel of a stereo pair, it WILL have a VERY negative (no pun
intended) sonic effect...
Mark