A good guess but again, this problem goes away when I use the HD650, confirming my equipment and ears aren't the problem.

Yes, this issue persists through all sources. For now I have set a gain of -1.2dB to the left channel to balance it out, a bit hesitant to open up the headphones.

Hello everyone, I've been using the DT1990 for about a month now and just today noticed that the right headphone was quieter than the left by around 1-2dB. I plugged my HD650s into my setup and the sound was balanced, while when I tried the DT1990 through my phone the sound was unbalanced. I...

  Would rather not wait 2 weeks for shipping. Does brand matter much? I think I'll go with http://www.ebay.com/itm/4-Olympic-6HA5-6HM5-Electronic-Vacuum-Tubes-in-Box-NOS-Matching-Set-/111572170113   Edit: Went ahead and purchased 2 GE 6HM5s, hopefully it'll be as good as I've heard, or at...

Should I buy the 6HM5 from thetubestore.com (they don't even tell you what brand or style it is short/tall) or just buy two different 6HM5 tubes from ebay? I don't see any matched pairs or sellers selling 2 in the States.

Well the price is certainly enticing. Do driver tubes need to be matched? Might go with this and see if it increases the instrument separation and make the treble less harsh.

  I can't find anything on the 6HM5 tube, was it a typo or are they extremely rare?

Hello, I recently purchased a Little Dot MKIII using the (6H30) and (M8100 / CV4010) tubes. I find the treble a bit harsh and grainy? As well as the instrument separation lacking behind the Magni. Which tubes give the best instrument separation/detail and smooth treble?   I was looking into...

Hi, just got the HD650s and I'm interested in beginning my journey into tube amps; Little Dot seems like a good place to start. What are your thoughts on the Little Dot MK2? Are there any cheaper options that sound just as good?   I really want to experience the "warm" tube sound and...

Is there a way to stop the extreme sibilance from female vocals on the HE-400? I have velour pads and an E17 with +2 bass, -2 treble. Should I look into doing some pad mods, or is there a way to EQ it out?

Add the HiFiMAN HE-400 and RE-400. Both have spectacular soundstage, better, wider, and more accurate than my A900 that's on the list.  

nevermind, found good deal on tubes

Thank you for the reply. I love your product and was devastated when the left channel no longer worked. Now I'm gonna have to deal with ****ty onboard audio until I can get the E17 replaced.

My E17's headphone jack just died, and I've only had it for 1.5 months. What can I do? Got from Amazon, so I guess return although it's past 30 days?

HE-400 without a doubt. Very satisfied with mine for all genres including EDM.