[wdoerr]

After scouring this site, I have been unable to answer the, seemingly, simple question: What do you do with the return wires?

Briefly, In a balanced cable you would have a signal wire, a return wire and a ground wire for each channel. That's 6 wires to solder to 3 plug connection points on the headphone jack.

Let's see, the left and right signal wires should be soldered to the left and right signal connection points of the plug. The left and right ground wires should be soldered to the ground connection of the headphone plug, separate solders (?). That leaves the two return lines unaccounted for.

Now I know why this isn't talked about, or photographed. It's probabally:
1) it's usefull information, therefore you can't have it (ie: a secrete), or:
2) I don't know what I'm doing and therefore don't want to look stupid.

There are two schools of thought:
A. Solder/Twist the returns together.
B. Solder the returns to the ground connection on the headphone plug.

So which is it?
A. Makes no sense, unless your looking for crossfeeds?
B. Ding, Ding. Ding?

 

[linuxworks]

a balanced cable is meant for a single channel, not stereo. normally.

are you trying to use balanced wire for single-ended connections?

 

[helzerr]

See this RaneNote to learn everything there is to know about balanced connections: Sound System Interconnection

 

[NightOwl]

Quote:

Originally Posted by wdoerr /img/forum/go_quote.gif After scouring this site, I have been unable to answer the, seemingly, simple question: What do you do with the return wires? Briefly, In a balanced cable you would have a signal wire, a return wire and a ground wire for each channel. That's 6 wires to solder to 3 plug connection points on the headphone jack. Let's see, the left and right signal wires should be soldered to the left and right signal connection points of the plug. The left and right ground wires should be soldered to the ground connection of the headphone plug, separate solders (?). That leaves the two return lines unaccounted for. Now I know why this isn't talked about, or photographed. It's probabally: 1) it's usefull information, therefore you can't have it (ie: a secrete), or: 2) I don't know what I'm doing and therefore don't want to look stupid. There are two schools of thought: A. Solder/Twist the returns together. B. Solder the returns to the ground connection on the headphone plug. So which is it? A. Makes no sense, unless your looking for crossfeeds? B. Ding, Ding. Ding?

If this is a poll, then I'll vote for #2

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif a balanced cable is meant for a single channel, not stereo. normally. are you trying to use balanced wire for single-ended connections?

This is what is being attempted. Two balanced signal cables to a single phono plug. It's physically possible, but not advisable.

You would solder the left and right signal wires to the left and right lugs on your phono plug. You would then solder the returns to the ground lug on the phono plug. If you attach the ground wires, then you would also attach them to the ground lug on the phono plug. Depending on the design of your balanced amp/source, you would then plug the cable in and get the marshmallows out to toast them over the fire you have just made.

Aside from the fact that you are negating your balanced inputs/outputs, combining the signal returns and/or attaching or not attaching the ground wires can damage the source/amp depending on the internal design of the source/amp.

 

[scootermafia]

Yeah, the point of balanced is to not only separate the negative/return wires for each channel, but to also separately chassis ground each channel's ground at the amp. usually the braided shield gets attached to the ground (X) pin on each end, then inside the amp it gets grounded somewhere.

Now where it really gets confusing is 3 channel amps where there is an "active" ground channel like my M3. Urg.

 

[Cabe]

An option that is probably preferable is to make the stereo pair properly with a Left and Right set of XLR (or TRS) connectors and then build some bodges to connect to those.

Unless you are running a balanced signal you only need one half of the cable, meaning you could in theory use you cable to carry a pair of stereo channels.

 

[linuxworks]

I was confused about balanced mode operation for a long time. it didn't help that many people think xlr=balanced and that xlr has 3 wires and so balanced 'needs 3' too.

it doesn't.

think of it this way (which is how it was explained to me). your phone wires are balanced! do they have 3 wires? no!! there is no ground and no NEED for a ground. in fact, with balanced, you can 'imply' a ground without ever having a real one around

also in car audio, they often run 'balanced' on wrong connectors (rca) and that has no 3rd wire; but as long as its twisted pair and not coax/shield style, you really ARE in balanced mode.

what is key: both wires are 'equally distance' from ground. either real local 3rd pin ground or some ground ref (in the circuit). both both wires are 'floating' and not grounded.

that's it! that's all you need for balanced mode. the receiver will do a 'diff' of the 2 wires and one WILL be out of phase with the other by very definition (ie, there is a voltage diff between them and that's what you are measuring).

ground is not needed. ground only adds more 'shield' and arguably, if your diff receiver works WELL the ground is not useful or needed. twisting the pairs gets each pair 'exposed' to nearby noise and so they cancel naturally when you invert one wire and 'add'. no shield or ground wire needed.

hth a little.

 

[NightOwl]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif I was confused about balanced mode operation for a long time. it didn't help that many people think xlr=balanced and that xlr has 3 wires and so balanced 'needs 3' too. it doesn't. think of it this way (which is how it was explained to me). your phone wires are balanced! do they have 3 wires? no!! there is no ground and no NEED for a ground. in fact, with balanced, you can 'imply' a ground without ever having a real one around also in car audio, they often run 'balanced' on wrong connectors (rca) and that has no 3rd wire; but as long as its twisted pair and not coax/shield style, you really ARE in balanced mode. what is key: both wires are 'equally distance' from ground. either real local 3rd pin ground or some ground ref (in the circuit). both both wires are 'floating' and not grounded. that's it! that's all you need for balanced mode. the receiver will do a 'diff' of the 2 wires and one WILL be out of phase with the other by very definition (ie, there is a voltage diff between them and that's what you are measuring). ground is not needed. ground only adds more 'shield' and arguably, if your diff receiver works WELL the ground is not useful or needed. twisting the pairs gets each pair 'exposed' to nearby noise and so they cancel naturally when you invert one wire and 'add'. no shield or ground wire needed. hth a little.

Well written and absolutely correct. The only thing I would add is that the connectors used (whether xlr, rca, or trs) should be the same at both ends of the cable since the impedance at either end should match. If a shield is used (and you are right, it is not needed as much as it would be with an unbalanced signal) then it shouldn't merge with the signal ground since this may create a ground loop.

 

[qusp]

yay!! well said guys; exactly the point. I dont often use shields at all, but I almost never use them on balanced signals. the balanced ICs (XLR) I use to connect my DAC to my active studio monitors are just twisted pair; now these wires pass several PSUs a couple of large CRT monitors and a wireless router. I have them on all the time and at the moment they are on 7 out of 10 volume, with no music playing, and not a sound is to be heard. in most cases they are redundant.

also for a balanced connection over one connector you need... yes; you guessed it, a 4 pin XLR, no ground needed or given. in which case you would just run 2 twisted pairs together in the one cable

 

[FallenAngel]

Quote:

Originally Posted by qusp /img/forum/go_quote.gif yay!! well said guys; exactly the point. I dont often use shields at all, but I almost never use them on balanced signals. the balanced ICs (XLR) I use to connect my DAC to my active studio monitors are just twisted pair; now these wires pass several PSUs a couple of large CRT monitors and a wireless router. I have them on all the time and at the moment they are on 7 out of 10 volume, with no music playing, and not a sound is to be heard. in most cases they are redundant. also for a balanced connection over one connector you need... yes; you guessed it, a 4 pin XLR, no ground needed or given. in which case you would just run 2 twisted pairs together in the one cable

That's a little dangerous. You NEED the ground between some sources and amps and between pre-amp and power amps especially.

 

[qusp]

yes thats the only time you would need it. but I dont NEED it in my situation and the outputs on my dac have only a shield grounded, so no I dont NEED ground at all. they are active monitors connected to a line level source. but you are right; any balanced connection that is carrying more current like you mention does need it, but headphone cables dont need it, and most line level situations dont need it. and thats the vast majority of situations covered right there at least here.

 

[FallenAngel]

I didn't think it was the amount of current that requires ground, it's the wish to make sure all grounds in the system are the simply connected.

 

[linuxworks]

I always thought the shield on balanced lines was supposed to be one wire, only (not connected at both sides, usually only at sender side). no ground loops that way and its NOT supposed to 'common ground' things - that's what a huge honkin' ground strap is for

 

[qusp]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif I didn't think it was the amount of current that requires ground, it's the wish to make sure all grounds in the system are the simply connected.

hehe..well yes.. but I havent come across one that has as yet. and I certainly wouldnt connect all the grounds in a system without knowing the ground potential of all the components and whether one may have an active ground for instance; should NOT be connected to one with a passive ground. not all grounds are created equal (unfortunately), so there is more to it than just connecting them all together. which should sometimes be avoided and can complicate things. I dont agree that all grounds in a system should be connected, only chassis grounds should be connected at the point the cable enters the chassis. but not all components provide chassis ground, so it gets kinda messy. if each system is wired that way then yes no problem, but still in this day and age manufacturers cant get their **** together and all use a common grounding scheme.

 

[FallenAngel]

With balanced there are no "active" grounds, they should all be PSU grounds (signal ground). Definitely not a good idea to connect chassis to PSU ground, but I guess sometimes you really just gotta crack open the devices and take a look.