I could be wrong, and this is just my personal opinion, but I think A&K has a deep sense of a personal pride in being one of the pioneers of 2.5mm balanced output. And similar to Apple with their stubbornness about lack of support for high-res Bluetooth codecs, it could take a while before they (A&K) will consider switching to 4.4mm BAL. But then, watch me eat my words if/when they release a new flagship with 4.4mm LOL!!!
I too don't think A&K would do that,
as the 4,4 mm is so much bigger, meaning lesser space for internal components, which is crucial for portable devices.
I like the 2,5 mm format the best, so much space and weight (especially weight on the side of the cable) saved. I actually dream of it being adapted on smartphones for which the 3,5 mm format is already too big, leading some companies to get rid of all jack connectors on their smartphones.
Actually I am personally strongly against the 4,4 mm format for the following reasons:
- the 6,35 mm is a standard so much established on the base of existing desktop , especially professional audio, devices that it just can't be done away
- the 3,5 mm is also so much established on the base of portable devices that it can't be done away
- the 2,5 mm is optimal for saving space and weight on portable devices, the 4,4 mm is much bigger and the jack much heavier so that by the definition of its size it will never be as much space and weight-saving as the 3,5 mm and more so as the 2,5 mm formats (BTW, I have always found the 2,5 mm connectors to be strong enough on AK players, never had any issues).
In conclusion, the 4,4 comes many decades too late to replace the 6,35 desktop format, and will never be ideal for the space-saving requirements of portable devices, so that it only creates complications by adding a further format to three formats already established.
Astell & Kern, for me you are doing right with the 2,5 mm balanced connector (plus the small enough 3,5 mm unbalanced connectors, the use of both small connectors avoiding confusions re. which connector is balanced or not), go on like this! You make the best portable players, you are the number one, don't let big consumer companies like Sony impress you.
I have one suggestion though:
Could you please consider adding support for Huawei's LHDC Hi Res Bluetooth audio codec?
I am mentioning this because Hifiman supports this codec for its Bluetooth receiver cord (e.g. for the coming BT Ananda) but they said that they will not support LDAC.
All the best,
bidn