Hope this tread is still alive:
To Isslewis:Yes, changing the fuses to HI-FI Tuning, is great just. But if You only changed 4, You surely are missing the one under the bottom cover of the amp. It is hidden under a plastic cover too.. And this one makes a big difference, I missed it myself , thats why I know...
My Tweaks:
I have fittet a Vincent powercord to my MK II with great result. Clears up the soundstage in a nice way. It seems to be sensitive to powercords.
I also use a symmetry box on the in my powerline and it makes a lot of difference. It works well with everything I tried it on. But the company that made them has closed, I am sad to say.
I have also changed the big and heavy speaker binding posts to a banana type. I have found some with very little mass. And I use bullet plugs for my rca. Sounds more natural than the types with lots of metal.
The tubes are Siemens cca (gold pins), think they are the best sounding tubes for this amp. With lots of air In the high notes.
The amp is standing on Solid-Tech: IsoClear feet from Sweden. They have a lot of small springs and keep the amp floating. Even thou it stands on a very heavy Audiomagic Hepta rack, they make a lot of difference.
Another thing to try out, is fitting short-wired rca plugs to the unused rca`s . Only the input ones of cause
!!! I have used WBT ones, and it makes a big difference in my set-up.. The soundstage becomes much better defined. Some sound recordings suddenly sound a bit narrow, and others sound huge, like they are supposed to, I guess.
From day one it has had a little hissing sound from the speakers, but dont` know how to cure it, Maybe somebody else knows this?
I am very pleased with this amp and is still looking for more tweaks and upgrades. But sending it to U.S. for major upgrades is not an option because of the shipping costs.