Defective or in need of burn in? Beyerdynamic DT880 600 ohm Repairs

Hello everyone, been a long time lurker of this forum and it's been a valuable asset for deciding on purchases, for that I want to thank all of you! This is my first post here.

About 4 months ago I purchased a pair of Beyerdynamic DT880 600 ohm headphones, they were incredibly bright out of the box but toned down a bit over time, 3 months into their use the right headphone completely died, I sent it in to Beyerdynamic's only US authorized repair center, they ended up replacing the system of the right headphone, and the connecting cord.

Unfortunately when I tested them out after repairs the replaced side was drastically quieter and less "bassy" than the left original headphone. The left phone has at least 300+ hours of burn in whereas the new (repaired right) one has only 10 - 12 hours, however the discrepancy between volume is roughly 20% - 24% (gauged by shifting the signal balance in an eq until the image seemed even), that is, the right repaired side was disturbingly quieter than the left, and I don't know if burn in will be enough to even out that huge volume difference.

Currently powering the unit with a Fiio E9, however I do not believe the amp to be an issue as prior to the right side dying the volumes we're relatively even ~ - 3% quieter on the right side.

At a loss as to what I should do, I've been burning in the right phone by sending all audio to the right channel through a bass heavy playlist, hoping to loosen up the drivers, but I can't forsee them getting a boost of 20% volume from being burnt in 200+ hours.

If the technician approved it, any ideas on what could be wrong? I emailed him directly but received no response. Thanks much for your time and expertise!

Quote:

Originally Posted by Solude 

If the sound is fine but low that would be poor driver matching.  But that drastic?  I'd almost look for some balance level in the system that was knocked/set/played with to get there.  

Thanks for the quick reply, initially I thought that was possible but I a/b tested the balance using my pair of Beyerdynamic DT 770 pros 80 ohms, and the image was almost completely even (~ -2% on the right), I've scoured every possible setting on my pc and believe that all balance settings initially were at dead center.

I'm not familiar with poor driver matching, could you explain that for me?

To be more specific on the volume discrepancy, the highs and mids on the repaired right seem to be -7% to -15% quieter, whereas the bass is at least -20% to -30% quieter and very shallow compared to the original left. 

Thanks again for your time!

*edit*
I've also flipped the headphones around on my head to make sure my ears weren't deceiving me and listened to them with the right side on my left ear and visa versa.

Bump :D

Quote:

Originally Posted by TC44 

If you have access to a multimeter you could take an Ohm reading of each driver.  My Dt880/250 read 246/247 ohms and sound balanced.  If there is a large discrepancy between the left and right, burn in won't make much of a difference.

Quote:

Originally Posted by Yoga Flame 

Do you have a multimeter? Try measuring the resistances of the left and and right drivers. This is done by clipping the multimeter leads to the headphone plug. Measure between Sleeve + Tip for the left side, and Sleeve + Ring for the right.

 

 

Since your left side is working fine, it should be around 600 ohms. If the right side is significantly different then something is definitely wrong.

 

[edit: looks like TC44 beat me to it]

Thank you both for the replies! Actually no I don't have a multimeter first time hearing of one, my budget is pretty tight at the moment but could either of you provide me with a link to an affordable multimeter unit?

[edit: Would something like this work? http://www.walmart.com/ip/Equus-3300-Hands-free-Digital-Multimeter/14644665]

Quote:

Originally Posted by TC44 

Nice pic Yoga!  Seasho, that Walmart meter will work just fine.  
 

 

 

Quote:

Originally Posted by Yoga Flame 

 

That one should be fine for this purpose. It would be hard for any multimeter to screw up a ~600Ω reading. For a long time I made do with a super cheapo digital multimeter for my DIY hobby and it got the job done. But if there ever comes a time you need a proper unit, this may be helpful: http://tangentsoft.net/elec/meters.html

Awesome, once again thank you both for your replies, this definitely gives me something to go on as it's been almost impossible getting ahold of the technician who did the work on my headphones. I think he's been selling refurb units on the sly under a different company name so he's not wanting to draw any attention to himself, not really my business but I just want to get the cans I paid for working xD. Also for thanks for the helpful links + pics :D

I'll pick up a multimeter asap, hypothetically what could it mean if both left and right were even in Ohms yet still had the volume discrepancy?

Quote:

Originally Posted by TC44 

With the difference in sound levels you're experience, it's almost certain your ohm readings will reflect.  Let us know what readings you get.
 

 

Thanks much! I definitely will. :D

Quote:

Originally Posted by roBernd 

swapped phase? ... but that would be quite silly.

Not familiar with that. roBernd, could you fill me in?


I got a multimeter and on the 200 ohm setting both sides read 00.3, not too specific but I'm guessing that means 600? That's also the smallest ohm increment on this meter :/