I’d hope not because that’s the point of a balanced signal which can be carried perfectly fine using 4 poles. I suspect it has something to do with the act of plugging-in and unplugging which can cause short circuits similar to what @wizardofoz was saying above. But I could totally be wrong-- I mean it’s usually good practice to have a ground so maybe it’s just for that reason alone…
My Sony cables looks like there is some kind of shielding on them,
but for example Alo Audio cables are not shielded https://www.aloaudio.com/wp-content/uploads/2018/02/SXC-8-44mm-to-Cascade.jpg
4.4 mm revisited to PENTACONN or not to …
My audio base is a Roon core (Linux) server. I now make anything DAC connected / Airplay based into an endpoint. Includes (standard res up to real HiRes DSD512) Musiccast speakers via airplay, mobile devices using Audioquest Dragonfly), Cambridge audio Dacmagic 100, iFi Zendac, TEAC UD-505 (plays native DSD and anything PCM, DXD).
Dear Gentlemen,
When you started this conversatiuon I was not yet aware of the existence of Pentaconn. Since then I have purchased a TEAC UD-505 balanced headphone amp/DAC which has two balanced headphone connections:
- 2x mono 6.35 mm jack sockets
- and you guessed it one 4.4 mm Pentaconn socket
My headphone is the Sennheiser HD 660s which comes with (amongst others) one 3m. Pentaconn balanced lead.
for the pros and cons of balanced/unbalanced etc. please visit: Balanced vs Unbalanced Audio Connections - Headphonesty
My headphone specialist (https://www.earsunlimited.com/) told me that there is now a real jungle of headphone connectors:
- Unbalanced: 6.35mm, 3.5mm (and all sorts of adapters).
- Balanced: 2x 6.35mm, 2x 3.5mm, RCA single plug 5 pin), RCA double mono plug 3 pin, (exotica like the 6 pin Stax headphone plug), etc.
The idea behind Pentaconn is that it can replace all of the above (balanced and unbalanced).
After Sony others have followed:
- Sennheiser (cable included with upmarket models)
- TEAC
- iFI (e.g. ZenDac)
The ZEndac is cheap, versatile, advanced and crosses boundaries.
- It is an ‘only’ USB DAC (PCM and DSD up to 256, and MQA renderer) and Headphone amp with, you guessed it, a Pentaconn headphone output on the front.
- however, is also has two analog oiutputs on the rear. The traditional analog double RCA, but also a Pentaconn output on the rear. This functions as a replacement for all traditional analog outputs (both balanced and unbalanced; as you can guessed with the complete spectrum of connector type in the universe).
I have connected it to a passice pre amp with a Pentaconn to RCA cable, but in the future (as I hope) one strand of Pentaconn can/will replace all things with two connecting cables (L/R) both single ended (unbalanced) and balanced.
A lot less cables behind your audio equipment, more stable connections, only one type, etc.
Hans
p.s. I am just a Roon & HiRes music fan and not a sales rep fort any of the above mentioned brands.
Bottom line is to enjoy music and not electronics 
Some examples
