I own both a Stax Omega MK1 and MK2. I listen from a BHSE with an AYON CD-5 as the source. I have owned all this equipment for over half a year and I have been enjoying the comparison of the MK1 and MK2- the only headphones I own and based on the headphones I have heard- the best headphones i have ever heard by far.
To start I wanted to say that the MK2 got a bad rap when they came out. To my ears they sound fabulous. The difference between the two is not enormous by non audiophile standards, but by audiophile standards the difference is undoubtaly noticiable although still- certainly not a big difference.
Let me start by saying that I tried lots of headphones in lots of systems and the MK1 was the only one my ears could stand as every other one I heard had trebblke peak and caused ear fatigue,- Until I heard the MK2. The distributer I bought them from gave me 45 days to compare them to the MK1 and if I wasant satisfied i could return them for a full refund.
At first comparison, they sounded so dark compared to the MK 1, but I had a feeling the sound might grow on me if I spent time with them. Well, I did, and the more I listened, the stronger the attachment I felt. The MK2's have a rounder, fuller, more analogue sound which draws me into the music. The MK1 had a crisper, cleaner, lighter, more open sound. The MK2's have a warm ambient sound wich is even more delicate on the ears than the MK1 which is very easy on the ears. I listen to both practically every day and it is such a close call- it is hard to say which is better. I find that even within the same song, I like certain passages more with the MK2 and certain with the MK1. I believe EQUAL but different would be more accurate than better or worse.
One suggestion for BHSE owners who are not that happy with their MK2. Try the GE or Sylvania Fat Boy tubes. Most all EL34 tubes sound 90% similar - with a thick warm midrange. The GE6CA7 is very different forom every other EL34. It is extrodairnaly aggressive, bright and more dynamic than standard EL34's. To me they are very similar sounding to the KT88 tube. As the coloration on the MK2 is overly full, and rich for some, these tubes- which outpower any other EL34 I know of push those drivers and break through that thickness. The results are just fantastic, and in my opinion much more substantial than any mod on the headphones themselves.
I can almost guarentee that in head to head comparison at a meet of for a short time , almost everyone will chose the MK1 over the MK2 becayse that crisper, more open feel gets you. However, the MK2 grows on you if you keep listening. They are so delicate and so at ease and that beautiful MK1 whallop we all hear in the MK2 is even thicker and jucier.. I am convonced that the MK2 will be looked at differently once people spend more time with them and give them a chance to grow on you. I am thankful I can keep both, but if I could ony keep one, it would be the MK2 because that analogue round flavor pullse me in in an irrrisistable way.
I tried the MK2 with other EL34 tubes which did not have the power, and dynamic punch of the GE6ca7 and in thise cases, the MK2's are just not at their best. So I can't say everyone would hold of the MK2 like I do, but for those with a BHSE, and these tubes- I believe thy won't be disappointed.