[TyMan]

Hey there! I've been lurking here for a while, and recently needed a headphone upgrade. Following the advice of users here as well as what I've found out from my own research, I decided upon the Beyerdynamic DT770 (250ohm version). They just arrived a day ago, and so far so good. Probably some of the comfiest headphones I've ever worn.
 
However, they're not playing stereo sound. Left and right channels are heard at the same volume in both ears. I've tried with several sources to the same result. I can set my source to 100% left or 100% right and I still hear it equally in both ears.
 
Currently, these are unamped. My amp should be delivered tomorrow, and I will give it a try and see if this resolves its self. Could this be the cause? From what I've read around here and other places, this shouldn't cause any damage either.
 
I know some headphones have a mono switch of sorts so I can just wear one ear, but it doesn't look like these have one. Have I made a mistake and purchased mono-only headphones? Nothing seems to indicate that these wouldn't be stereo. The jack is most certainly stereo.
 
Having just realized this issue, I'm (hopefully understandably) rather anxious and concerned about my purchase. Quite bummed out that these aren't working out for me after waiting more than a week on shipping, and even more bummed at the idea of waiting even more for a replacement. Any help is much appreciated.

 

[PurpleAngel]

Are these brand new DT770s or used?
Have you tried them using both the 3.5mm jack and the 1/4" adapter?

 

[TyMan]

Bought them from Guitar Center and the receipt says they're new, so I guess I'll have to trust that. They don't seem worn.
 
I've tried the 3.5mm jack on my desktop, laptop, and phone and the 1/4" adapter on a mixer. Still mono with both. All sources play stereo just fine with different headphones.

 

[PurpleAngel]

  Bought them from Guitar Center and the receipt from says they're new, so I guess I'll have to trust that. They don't seem worn.
 
I've tried the 3.5mm jack on my desktop, laptop, and phone and the 1/4" adapter on a mixer. Still mono with both. All sources play stereo just fine with different headphones.

 
I'm guessing the right and left channels are some how connected to each other (maybe inside the 3.5mm jack).
Seems like you will need to swap the headphones.

 

[Filter500]

They're definitely defective.

 

[TyMan]

Alright, thanks for the help guys.
Will go get a replacement in the morning.

 

[TI1358]

Hi,
 
I know this is an old thread, but it was a "Goolgle Whack" for my problem, so I'm posting my solution here for all who follow...
 
I've just spent about six hours trying to work out why (when recording with Reaper) the mix in my headphones was in Mono ...I've installed new ASIO drivers, gone through every setting in Windows 7 and Reaper ...you name it, I've done it!
 
It never dawned on my that it might have been my DT770's ...finally, I checked them <gaaahhhhh>
 
I checked the impedance across the Gnd--Left and Gnd--Right with the resistance setting on my cheap chinese multimeter ...47ohms - which, given the equipment, is close enough to HALF the expected value (80 ohms) ...Right. So the drivers are in parallel (80 in parallel with 80 is 40) ...For now, I'm going to assume the error is a) cheap multimeter and b) I'm measuring impedance with a resistance measuring device [I know VERY little about analogue electronics].
 
So I pulled them apart - which turned out to be more tricky than it should as the screws used by Beyer were different sizes in each side on the left can, and made of something resembling tissue paper - so I managed to strip the head off one of them!
 
Once inside I was disappointed to find that they really had been thrown together
 
...The wires to the driver were not in their grooves and close to shorting-out ...I moved those with a cocktail stick and much cautious trepidation ...No fix
 
...I checked where the sleeving had been stripped (in the "factory") and found the cores had been damaged - so I cleaned those up ...No fix
 
The solder had grown whiskers [this is a known industry problem, especially with Lead-Free solder] so I cleaned those off [cocktail stick, less caution, no trepidation]  ...No fix
 
Through all this - AT NO TIME could I read a short (or even a high resistance) between the Left and Right pins of the 1/4" plug.
 
I was baffled!
 
Finally I removed the 1/4" adaptor and would you believe it, the problem disappeared! ...STILL with a "no short" across the adaptor with the multimeter!
 
I replaced the adaptor with a spare ...Problem fixed.
 
I tried to use the Beyer adaptor with another 3.5mm jack, but "normal" 3.5mm plugs don't fit in it.
 
I still don't know what or why - but after an hilarious amount of pain, it turned out to be the adaptor ...Oh, and my meter is now reading 88.8 ohms for each driver (in case you care)
 
TI