[roadrat]

I have my Sennheiser IE900 with 4.4 cable for use in my Walkman. Occasionally , I would like to connect to the to 3.5mm output of my Xperia without changing cables. Can I use a 4.4 female to 3.5 male adapter without any issues? If so, can you recommend one?

 

[kaeswiss]

There's no problem going from 4.4 to 3.5. I got my NiceHCK adapter from AE when I bought some of their cables.
https://www.aliexpress.us/item/3256803042731775.html

The only issue I have is that when the 4.4 cable plug is connected to the adapter, the combined length is almost as long as my portable dac/amp (FiiO BTR7). I don't use the adapter much, but if you plan on using it a lot, I recommend getting one that's more like the ddHiFi style. I think this shape would be less prone to accidental damage.
https://www.aliexpress.us/item/3256805277643019.html

 

[dunring]

I use a multi kit with ends that quick change and it's really convenient. You can go from balanced 4.4 to se 3.5 but not the other way around, so it's safe. It's probably closer in price to just get a cable kit, mine was $30 on Amazon but AliExpress has them for $15 with three connectors.