Building balanced headphone cables?

[DualTriode]

Hello All,
I have not ever held in my hand a set of balanced headphone cables. I have seen and read that they can cost a lot. I do not want to pay more for the cable than the Eletra-Print Audio balanced output transformers. My goal is the most fidelity for the buck, euro whatever. The tubes were $ 0.35 each.
Is there an industry standard plug? Separate plug for left and right? Or a single plug for both? Locking din, XLR or TRS? Metal or plastic? The amplifier output will be built to match.
At the headphone end of the cable are those plugs proprietary or can they be purchased from Digikey or where ever? Or clipped off a factory replacement cable?
The cable itself is it a separate shielded cable for each ear or what? If both ears are inside a single shielded cable will there be cross talk? Silver plated is in the budget. Solid silver is too rich.
Thanks
DT

[Steve Eddy]

Originally Posted by DualTriode

Is there an industry standard plug?

Nope.

Separate plug for left and right?

I think dual three pin XLRs is the most retarded thing ever cooked up. It's popular, no thanks to Headroom, but no one actually likes it. A single XLR is bad enough. But really, who wants two big goat testicles dangling from their headphone cable?

Or a single plug for both?

That's what I would recommend.

Locking din, XLR or TRS?

Mini XLR is a good choice unless you're using 18 gauge wire for your headphone cable.

Metal or plastic?

Flip a coin.

At the headphone end of the cable are those plugs proprietary or can they be purchased from Digikey or where ever? Or clipped off a factory replacement cable?

Which headphones?

Most headphones have the cable wired directly into them. Sennheiser uses two different types of connector, one on their HD-580's, 600's and the like, and a new one on their HD-800's. Cardas makes aftermarket connectors for the former, and I can't recall off the top of my head who's selling the latter. Just Google "hd-800 connector."

The cable itself is it a separate shielded cable for each ear or what?

Can be depending on who makes it. Personally I don't see any need for shielding.

If both ears are inside a single shielded cable will there be cross talk?

Some. Whether it's meaningful is arguable.

se

[Gordy]

Double 3 pole XLRs are an unfortunate hangover from HeadRoom promoting it for their own benefit.

A miniature 4-pole connector would be neat at the amp end of the cable, but would restrict you to your own amp because other amps are unlikely to ever have a matching connector. A single 'normal size' 4 pole XLR would be very sensible as this is likely to become some form of unofficial standard in the market methinks.

Personally, I would go for metal shell. (Objectively more sturdy to cope with insertion / extraction. Subjectively feels more positive to the hand and looks more professional to the eye).

Shielding works as sheilding (yes, really). It's also a real-world advantage when smaller gauge conductor wires are used, as it helps add strength to flimsy cables.

[Steve Eddy]

Originally Posted by Gordy

Double 3 pole XLRs are an unfortunate hangover from HeadRoom promoting it for their own benefit.

Yes.

From what I understand, when they first started messing around with "balanced" headphone amps ("bridged" is a more meaningful term to describe what Headroom promotes as "balanced") they used two separate stereo amplifiers with their channels bridged. So with two physically separate amps, you needed to physically separate connectors.

The problem is that when they started making "balanced" amps in a single chassis, instead of switching to a single connector, they kept the dual three pin XLR's.

Stupid.

A miniature 4-pole connector would be neat at the amp end of the cable, but would restrict you to your own amp because other amps are unlikely to ever have a matching connector. A single 'normal size' 4 pole XLR would be very sensible as this is likely to become some form of unofficial standard in the market methinks.

Yes. I think a four pin XLR is an ok compromise.

Shielding works as sheilding (yes, really).

I think it's overrated. Especially for headphones (the voice coil makes a nice antenna). About all it really does is add more capacitance.

It's also a real-world advantage when smaller gauge conductor wires are used, as it helps add strength to flimsy cables.

Then don't use flimsy cables.

se

[jcx]

Ray Samuels is pushing a Kobiconn micro 4-pin camera iris control connector for IEMs:

The RSA Protector balanced portable: Images and impressions 1st page, Please post your impressions . . - Page 4 - Head-Fi: Covering Headphones, Earphones and Portable Audio

Lemos look nice too


the totally insane could use 8 pin connectors - Kelvin force/sense for each wire of the headphone cable - no contact resistance worries

extend to the drivers? - I've closed >100KHz gain intercept frequency feedback loops over 100' of twisted pair in strain gage transducer amps


wonder what the cable fetishists would have to say about that

[DualTriode]

Hello All,
Thanks for the output guys and se it looks like you are a neighbor.
Sounds like nothing is cast in concrete. The first effort will be the parts that I can find in the old library card index where I store things. I have some milspec silver plated wire I will braid up, ooh pretty colors.
Thinking of cables, the TRS output at the typical amplifier has a common ground. The ground is common to both output transformers. A replacement set of headphone cables need not share a single return path, each ear can have a separate ground all the way back to the output jack that by its self may be a good start towards determining if HeadRoom really made all this stuff up.
DT
All just for fun!

[Steve Eddy]

Originally Posted by DualTriode

Thanks for the output guys and se it looks like you are a neighbor.

How would you know? *closes all his drapes*

The first effort will be the parts that I can find in the old library card index where I store things.

Cool! You have one of those too? I have a nice one in maple made by Remmington Rand back in the 50s. Hiram Johnson high school was getting rid of theirs because their indexing on computer and my mother was a custodian there so I was able to get one.

As a side note, I think it's a bad idea to eliminate the card catalogs. Some years back I went over to the library and all the terminals were down. Apparently a work crew had dug up some phone lines in the area.

So I asked the librarian where the card catalog was.

"Oh, we got rid of those."

*sigh*

Just as there's still something to be said for dual triodes, there's still something to be said for good ol' ink on paper.

I have some milspec silver plated wire I will braid up, ooh pretty colors.

Far out, man! Hmmm. No "trippin" smiley. Just use your imagination.

Thinking of cables, the TRS output at the typical amplifier has a common ground. The ground is common to both output transformers. A replacement set of headphone cables need not share a single return path, each ear can have a separate ground all the way back to the output jack...

Yeah, but that's not going to address the biggest "problem" which is the common contact resistance of the TRS.

All just for fun!

That's the spirit!

se

[BoilermakerFan]

If you are DIY'ing your amps, then I'd also agree that the 4-pin XLR is a great jack and plug combo to use. The mini-XLR version is becoming very popular on single entry headphones like AKG and the new Audeze LCD-2 uses them on each ear cup. The 4-pin mini-XLR would be a good candidate for a balanced portable amp, especially if you designed it with THAT ICs to split the SE input into balanced. Adapters aren't hard to make either.

The other issue with TRS is that they short when inserting and disconnecting, so you have to account and protect for that with you builds. Many a Beta22 amp has been sent up in smoke because somebody forgot to turn it off before removing the headphones... My F5 will have resistors on the TRS jack to keep the short from blowing the outputs, if I even bother putting a TRS jack on it.

I love the MIL-SPEC Alpha brand stranded SPC. Eight 28awg wires per cable, 4 per channel, is a really nice, durable cable.

All of my cables are being reterminated to 4-pin XLRs. I'm making an adapter box to allow my cables and headphones to run off any amp though, whether it's a SE 1/4" TRS or dual 3-pin XLRs. Flip side is also being addressed, any other cable termination can be adapted to my amps. Actually considering using my balanced TPA Darwin for this role.

[DualTriode]

Hello BoilermakerFan,
Do you build them or drink them, or both?
Everyone,
I am sitting here with both he and she parts of TRS’s in my hand. The she part has a plastic body. I do not see where a short will happen. Perhaps a metal body grounded to the chassis could cause a short. I prefer the plastic body that does not ground to the chassis. How / where does the short happen?
The current application is a Single End Triode. The output transformer is balanced (Thank You Jack at Electra-Print). The secondary winding is center taped and grounded making the output balanced. Do not pull the plug on this one when it is operating either.
DT
All just for fun!

[Steve Eddy]

Originally Posted by DualTriode

Everyone,
I am sitting here with both he and she parts of TRS’s in my hand. The she part has a plastic body. I do not see where a short will happen. Perhaps a metal body grounded to the chassis could cause a short. I prefer the plastic body that does not ground to the chassis. How / where does the short happen?

I think what can happen is, while removing the plug, the ring contact on the jack can contact the tip contact of the plug while the tip contact on the jack is still contacting the tip contact of the plug. The result being that the two channels' outputs get shorted to each other.

se