I have the same set-up!

+1   Went on trip a while back. Using only ATH-WS55 for the duration. Listening to music suddenly becomes a diversion instead of enjoyment...

  Buy a cheap tube to test and see if the problem goes away. Could be just a bad tube. You can get a 6922EH or a JJ E88CC (even used) for just a few dollars.

  Don't know. But I'm using 6H30Pi EB.   Rated for 5000~ 10000 hrs.

Update on Sovtek 6H30Pi Initially it shows slight improvement over the stock 6922EH. I am not very impressed. After 2 weeks of about 30 hours of listening, I start swapping back and forth between the 2 tubes again. This time, the difference is very significant.   - The new tube has much more...

Got my T1 about 5 months ago. Did the first tube swap Friday. Since I'm not too keen about OS tube as they are not sustainable. The tube I got is Sovtek 6H30Pi as suggested. It is definitely an improvement over the stock 6922EH in general. Treble is less hot and the bottom is fuller. The tube...

  2 x 100 watt to drive the toaster.   ummm... so that's 100 watt per slice... ; )   Beautiful!

  I am driving my Q701 with the T1. The other items that I can compare to is E17 and computer audio out (Realtek....).   Computer audio out: - Max out on volume to get barely acceptable volume - level of detail 50% - sound separation between different sources of sound 50%   E17: - Gain...

  I have both K550 & Q701. If you use Foobar as your player, you can dial down the shrill by reduce 5 & 7 kHz by a notch or two using the built-in Equalizer. (If you have a Equalizer with a finer scale, that'll be 5,6 &7 kHz) The shrill will magically disappear. But don't overdo it, otherwise...

  Just a reminder, don't forget to menton the power supply voltage. I seen some email people getting wrong voltage units. The power supply's output is a -15-0-+15 AC brick. It is not rare but not as common as you can grab from any electronic store.

  I was looking well before I made my purchase. It took too long to wait for the drop to happen and another long wait for the delivery. Since there's only $10 difference in final cost. I bought it somewhere else.     I bought mine from here:  ...

Till you hear Aune T1 + Q701, you'll be surprised by how much better in sound separation and detail these headphone can get. I was very surprised when I first heard E17 + Q701. Sound that I don't even know exist with my previous setup. Then came along the AuneT1... now I'm not just acknowledge...

    I just received Aune T1 w/6922EH last week. And I use E17 before as DAC/Amp with my Q701   Aune T1 absolutely improve on every aspect over E17 in terms of sound quality.   ie Detail, low end authority, sound separation, sound stage (depth), sound seemed fuller across the spectrum.  ...

  At least for mine and a few others who mentioned in this thread, a brand new K550 is unbelievably bad. Low frequency completely absent. It is like listening to AM radio. It will take a day or two for the bass to come out. The piercing high is the illusion when the low are absent.

  Very good observation! The OD becomes smaller but keeping the ID more or less the same. This gives an illusion that the padding becomes thicker.   In fact the smaller OD should fit more different head shape. Hence a better seal for someone who have had difficulty before. Good move by AKG. ; )