[LNuneek]

I'm on my quest to replace my ATH-M50. Had it for many years, it's old, and I want a change. I'm leaning ATM most heavily towards purchasing a DT 770. I think I will really enjoy having my own pair of these. However, as I started digging further into information about them, I keep running into info. about recurring issues. Mostly such things as one of the channels going dead, or loud popping or cracking sounds when the headphone is moved or adjusted, rattling noises inside the cup, loss of bass in one channel, losing the ability to handle bass and distorting, etc. I also see a lot of people who have a certain issue, get a replacement DT 770, and that one develops the same issue as well.
 
I'd like to be sorted out on the overall quality of this headphone, cause I'm really starting to get the impression Beyerdynamic has huge quality control issues with their cans. It could be also that the can is so popular that it just seems their QC is out of control just because of the sheer numbers of these out there, and the incidence of QC issues is actually on par with typical occasional hiccups in manufacturing that happens with most products.
 
Let me know your experience with the DT 770 and possibly if you have more insight into the actual QC of them.

 

[rhythm is life]

I replaced my M50 with the DT 770 3 years ago. Went through 2 pairs before giving up and going back to the M50. My 2 DT 770s had bass rattling in the left earcup, eventual loss of bass in the left channel, and massive bass distortion at high volumes. Usually when a headphone has been around for over a decade, the kinks get ironed out (see Sennheiser HD600/650). Not so with the DT 770.

 

[LNuneek]

Yes this is exactly the scenarios I keep coming across when researching the DT 770.

 

[Beencredible]

Only problem I had was the cable cutting in and out at the source. That happened less than 30 days in so I exchanged it and it has been working flawlessly for years now.

 

[Bugler]

I have been searching for a closed back headphone to compliment my beloved HD650 to use when background noise (wife, tv...) interferes with my music listening. Though I prefer speakers, cans sure have their place. I spend most of my waking hours listening to music (stuck home on disability battling stage 4 cancer). I was also looking for something with velour earpads like the HD650. I hate the more common pleather. A member of my audiophile group loaned me his DT770 Pro 250 ohm for a test drive for a few weeks and I love them. He used them daily for a couple years and so far with no issues. They sound great and are very comfy. I ordered a 400 ohm pair today and am quite anxious. Sorry I can't be more helpful about QC.

Update: Though they were listed as 400ohm I received them today and they are in fact 250ohm.

 

[Sillyness]

I'm taking mine apart for the first time in 8 years. I have a slight rattle in the right channel that I believe is attributed to a caught hair. It seems this isn't an uncommon issue, but pretty easy to fix.
 
I don't know how different they are nowadays, but mine have kept me happy this entire time. I would recommend them based on my experience. Also, I'd like to mention that, although I do cherish them, I haven't always been the most gentle of owners. I would actually say that they have excellent build quality.
 
Edit: Yup. That's one hairy driver. Geez, you can even see it in my crappy photo:
 

 
The rattle is totally gone and I now have zero complaints over 8 years. In fact, there was so much hair in there that I'm going to do the left side too.

 

[bar1]

I'm the owner of several Beyerdynamic products (DT770, DT770Pro (3x), DT880 (2x), DT990, lots of microphones). Have never needed any repair, except hair-removal and change of ear-pads.
Bass-rattle is almost always a hair (your hair) that is fused to the diaphragm of the driver or to the thin paper covering the diaphragm.
My Beyers are never used portable but see some heavy use. All DT770Pro and one of the DT880 are used in a studio setting.