heh, but seriously.

If you only have room for a single jack, and want to support balanced (4-channel bridged) and single ended cans, what do you do?

Two options as I see it.

Use 4-pin jack and tie ground to the shell and/or case or use a 5-pin jack and have a dedicated pin for ground. If the first case, I'm not sure if there are 4-pin female jacks where the where the "shell connection" can be isolated from the case. If this isn't possible, then is 5-pin the only real option?

I cannot believe this hasn't come up before. Thoughts?

I think there is some standard, IEC or something, which specifies a 5 pin xlr for balanced headphones. It does make a good deal of sense.

It would make sense if anyone else did it. Go 4 pin or go home

It would make sense if anyone else did it. Go 4 pin or go home

meh. I'd like a way to convert to single ended and only have a single jack...

sorry, no way no how can you convert 4-pin to single ended.

what if your amp design allowed the 2 minus outputs to be shorted

heh, you're quick. I cannot see why that wouldn't work, but then again, I could imagine designing for that condition..

Edited February 1, 201016 yr by luvdunhill

I cannot believe this hasn't come up before. Thoughts?

Yeah, what are you doing with the 5 connections? I understand 4 of them: +/- L/R, but the 5th one eludes me. I'm with grawk -- 4-pin, a la AKG K1000.

Oh, it's L+/L-/R+/R-/GND so that you can tie in just L+/R+/GND for single ended and not cross grounds.

right. otherwise, there isn't a way to connect a single ended headphone to a 4-pin jack.

You said the method at the top. Tie the shell to ground. But I don't think I'd go out of my way to provide that option anyway.

I'd be worried about noise in that case. If the shell cannot be isolated from the outer connector, it could be a source of ground loops and other nasties. Why not go through the trouble of supporting single ended headphones?

So make room in the case for a single ended jack?

So make room in the case for a single ended jack?

I only have room for one jack

back panel

back panel

no room. Top is completely covered too

I see room on the sides

Oh, it's L+/L-/R+/R-/GND so that you can tie in just L+/R+/GND for single ended and not cross grounds.

right. otherwise, there isn't a way to connect a single ended headphone to a 4-pin jack.

You mean, three-connector, right? Because all dynamic headphones are two single-ended drivers. It's just a matter of how easy it is to access that point where the 3 wires become 4, right?

I agree with "provide a separate jack" for those.

I think he means without rewiring the headphones, or reterminating, etc.

No, I don't think he means that, since he's talking about a 5-pin jack -- he'd have to do that anyway.

adapter cables

wait, I thought about this... even if you can do this (which by the way, I thought of a case where you could do this, a concertina output 'cause I did this in my preamp, but not much good at driving much of anything), how would this work with a single 4-pin jack? just because you can short the minus to ground, doesn't mean you can short them to each other and get a usable reference

and, Dusty I just mean use a single jack. You need a ground reference for the single ended headphone option. Adapters are fair game.

All this to say, I think finding an isolated four pin jack with a separate shell connection is the way to go...

Alright, so the two hots go to L/R +; ground gets split and sent to L/R - of the drivers. Right so far?

On the amp side of the same sitch, where does L/R - go? Unterminated? Loaded? Switched-in-loads? Switch out those half of the amps (so that they don't present some weird load, and yet are green and don't consume power at the same time)?

The case I am discussing is the unreterminated single-ended headphones discussed earlier.

Not sure about that shell connection.

Acoustic Revive RGC-24 Ground Conditioner

A blend of special ores is clearly the solution

Dusty:

Yeah, that's right. So far. So, you're asking the same question on the amp side. The L/R- is unterminated. I definitely don't want a switch there.

So, in summary the problem is with a 4-pin jack, or even two 3-pin jacks, that are used on the output of a four channel design, you cannot "convert" this using any combination of adapters, custom or otherwise, for use by a single ended terminated headphone. You need a ground reference.