That's pretty standard even in newer Sennheisers. I think HD 650 and above you get the big plug. Some might come with two cables, one with a standard plug and one with the bigger.
I bought new Sennhrisers every few years for the last 10 years. They randomly stop working. This time I bought Sony, no much hope, though. I just got used that keyboards, mouses and headphones are to be replaced every few months or years if I’m lucky.
I've had Sony MDR-7506s for about 7 years now, two cup replacements but otherwise going strong. I've also had my Audio Technica ATH-M50 for a solid 12 years, one cup replacement, sound great and work perfectly.
I have basically worn one of those two pairs of headphones every single day at work since I bought them; I guess I've just had good luck.
Which Sennheisers? Their 25 Euro in ears broke on me as well (C25x?), but as a pupil I couldn't afford better and just burned through some of those. Time lapse to a decade later, and I got myself the HD650. They sound exceptionally while still being relatively affordable (not that this would still be an issue, but I'm not a maniac who spends all their money on audio equip) AND they can take some abuse. At least that's what long time owners report, and that's also my own limited experience after 4 years - I take care not to trip over the cable and throw them across the room, but that's about all the care they get from me. [edit: okay, and if I stuff them in a bag, I'll stuff them on top or put some clothes between them].
Not really. I took a look at kind of a cable Sennheiser bundles with each headphone from the website:
HD 559: 6.3 mm plug.
HD 560 S: 6.3 mm plug.
HD 569: 6.3 mm plug + 3.5 mm plug.
HD 579: 6.3 mm plug.
HD 599: 6.3 mm plug + 3.5 mm plug.
HD 600: 6.3 mm plug.
HD 650: 6.3 mm plug.
HD 660 S: 6.3 mm plug + 4.4 mm balanced.
HD 800 S: 6.3 mm plug + 4.4 mm balanced.
HD 820: 6.3 mm plug.
So really the 3.5 mm cables are an exception that are also bundled with Sennheiser's audiophile-tier headphones and absolutely everything has a 6.3 mm plug out of the box.
That 6.3mm / 1/4" plug is 3.5mm + converter (you just pull it apart comes apart into two pieces), at least on 5xx and 6xx range. It's not even screwed on, just a tight friction fit. Unless, that is, Sennheiser decided to cheapen out in the last 10 years and redesigned them...
Never had original 8xx cables to check but I would be surprised if they weren't the same.
Which means that they have indeed cheapened out with a recent refresh - which is a shame. I have the cable I describe on the headphones I am quite literally wearing on my head at this very moment (HD 600) and identical ones were present in 59x and 650 from the era. Glad to know, TIL.
Edit: the 3.5mm male to headphone is Sennheiser 81435 [0] the 6.3mm male to 3.5mm female that fits over it is Sennheiser 562507 [1].
I bought the HD600 last year and it came with the 6.3mm to 3.5mm removable adaptor. This was in Europe maybe the cabling is different, or there are multiple packagings for different use cases (likely). The cables are removable so its easy for them to have different SKUs.
I don't think it's about ancient compatibility but rather just the fact that audiophile stuff tends to have it and if you are marketing to audiophiles, might as well design it that way. I have a pretty modern stereo receiver (Onkyo A-9010) as my computer's headphone amplifier and it has the bigger socket only. Same with my home theatre receiver (also an Onkyo).
But I believe there's no difference in listening experience. The bigger plug is probably a lot sturdier though. I've had some 3.5 mm jacks bend on me. Can't imagine that on the good ol' 6.3. I have totally busted a 6.3 mm to 3.5 mm adaptor though.
As others have stated, it's usually more about compatability. Most (nonportable) headphone amps will have a 1/4" plug rather than the 3.5mm, and it makes more sense from the "female" amp side to convert the larger 1/4" --> 3.5mm than the other way around. Many home "audiophile" headphones I've used (Audeze or Beyerdynamic) actually have the smaller 3.5mm jack, but because they are so focused on home use (bulky, open backed, expensive, and not very shovable into a backpack), users rarely use them connected to a phone or laptop.
There is no signal or quality difference between different sizes of headphone jacks, except that bigger ones might last longer.
For very long cables or high RF you might want a kind of cable called "balanced", which comes in every size except 3.5mm. Some audiophiles think these make headphones sound better, but it's probably not true.
its standard in audio. all mixers, guitar amps etc support them. big plug means stable wide signal, and it does not break. never had one break ever. even the shitty cables. they are well shielded.
That's pretty standard even in newer Sennheisers. I think HD 650 and above you get the big plug. Some might come with two cables, one with a standard plug and one with the bigger.