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Four pin XLR "standard"

post #1 of 12
10/3/09 at 9:36pm
Thread Starter 
What's the ipso facto "standard" for four pin XLR headphone plugs/cables?

Thanks!

se
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post #2 of 12
10/3/09 at 9:57pm
It's based on the K1000 pinout which is available in the K1k user manual and on quite a few of Pete Millett's schematics.

1. L+
2. L-
3. R+
4. R-
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post #3 of 12
10/3/09 at 10:04pm
Thread Starter 
Quote:
Originally Posted by n_maher View Post
It's based on the K1000 pinout which is available in the K1k user manual and on quite a few of Pete Millett's schematics.

1. L+
2. L-
3. R+
4. R-
Great!

Thanks, Nate!

se
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post #4 of 12
10/3/09 at 11:26pm
Happy to help.
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post #5 of 12
10/3/09 at 11:50pm
Hehe I actually have a screen cap of another of your posts answering the same question filed away here.
It helped heaps
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post #6 of 12
10/3/09 at 11:58pm
Thread Starter 
Quote:
Originally Posted by n_maher View Post
Happy to help.
Well if that's the case, I have a fruitless mullberry out front that needs to come down. What are you doing next weekend?

se
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post #7 of 12
10/4/09 at 2:48am
Although, I am not sure why the 4-pin was adopted as "standard" when there already was an internationally adopted standard for dual/stereo balanced signals, which is the 5-pin XLR, with well-documented pinouts.

Granted it's not too common to see 5-pin XLRs in use but to my defense I have seen at least one commercially produced product with a 5-pin stereo XLR output.

The 5-pin XLR is a lot more versatile because it is possible to draw a single-ended output from a 5-pin jack (the "extra" pin being the ground pin), whereas it's impossible to do so from a 4-pin jack.

I'm personally using 5-pins in all my headphone balancing efforts but it's a rather lonely battle.
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post #8 of 12
10/4/09 at 3:01am
Thread Starter 
Quote:
Originally Posted by doobooloo View Post
Although, I am not sure why the 4-pin was adopted as "standard" when there already was an internationally adopted standard for dual/stereo balanced signals, which is the 5-pin XLR, with well-documented pinouts.

Granted it's not too common to see 5-pin XLRs in use but to my defense I have seen at least one commercially produced product with a 5-pin stereo XLR output.
Yeah, though we are talking about headphone outputs here, not line interfaces where four of the five pins serve as left and right balanced lines and the fifth as "pin 1."

Don't need a "pin 1" for headphones.

Quote:
The 5-pin XLR is a lot more versatile because it is possible to draw a single-ended output from a 5-pin jack (the "extra" pin being the ground pin), whereas it's impossible to do so from a 4-pin jack.
Oh no, it's possible.

Edit: And it's also possible to do it while maintaining a balanced output to the headphones.

Quote:
I'm personally using 5-pins in all my headphone balancing efforts but it's a rather lonely battle.
Well, if you get too lonely, you're more than welcome to join me in trying to snuff out dual 3 pin XLRs.

se
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post #9 of 12
10/4/09 at 3:08am
Quote:
Originally Posted by doobooloo View Post
The 5-pin XLR is a lot more versatile because it is possible to draw a single-ended output from a 5-pin jack (the "extra" pin being the ground pin), whereas it's impossible to do so from a 4-pin jack.
Use the shield connection.
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post #10 of 12
10/4/09 at 3:12am
Well, as far as I know converting 4-pin output to single ended may be perfectly OK in certain instances, but not ideal in other topologies. Essentially, you'd be shorting the -'ve outputs of each channel and I thought this can causes issues in some scenarios...?

Also, the shield connection isn't necessarily "connected" i.e. if the chassis isn't properly grounded... right?

Ah, maybe I'm wrong...
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post #11 of 12
10/4/09 at 3:27am
Thread Starter 
Quote:
Originally Posted by doobooloo View Post
Well, as far as I know converting 4-pin output to single ended may be perfectly OK in certain instances, but not ideal in other topologies. Essentially, you'd be shorting the -'ve outputs of each channel and I thought this can causes issues in some scenarios...?
Yeah, generally, amplifiers don't like driving each others' outputs.

But if your output is transformer coupled, it's a piece of cake. You can simply tie the end of each transformer's secondary to the TRS ground terminal. And the headphones are still being driven from a balanced source so it's not even single-ended.

Quote:
Also, the shield connection isn't necessarily "connected" i.e. if the chassis isn't properly grounded... right?
Right. There wouldn't be any guarantee of it in every piece of equipment, but it could easily be exploited in a DIY situation.

se
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post #12 of 12
10/4/09 at 5:19am
since we're on the subject should balanced have different plugs for phones and cables (like single ended has rcas and phono plugs)?
Seems dumb to use the same connector. Obviously that leads to confusion.
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