Mahalo Roesch,
I had the bias settings to the recommended left end of the bubble (as suggested by Scott at the Analog Room) too. But I found that old stock Tung Sol 6550s, both greyplate and blackplate (no holes), sounded better biased lower.
New issue 6550s and KT88s I've only tried at the recommended bias settings, but I will try a bit lower setting to see if that changes the sound for the better. Thank you for the suggestion and even more for the report of improved results.
I too have experienced that the Air Tight ATM-2 can sound "lean and pitched-up tonally," as you describe it, though this varies from CD to CD. I've consequently gone away from silver ICs (Audioquest) and back to copper (Verbatim and Cardas).
Where do you set the bias? I've just tried lowering it by two markers and noticed resolution in the treble range is improved, but only slightly. I'm using SED KT88s now.
I had the bias settings to the recommended left end of the bubble (as suggested by Scott at the Analog Room) too. But I found that old stock Tung Sol 6550s, both greyplate and blackplate (no holes), sounded better biased lower.
New issue 6550s and KT88s I've only tried at the recommended bias settings, but I will try a bit lower setting to see if that changes the sound for the better. Thank you for the suggestion and even more for the report of improved results.
I too have experienced that the Air Tight ATM-2 can sound "lean and pitched-up tonally," as you describe it, though this varies from CD to CD. I've consequently gone away from silver ICs (Audioquest) and back to copper (Verbatim and Cardas).
Where do you set the bias? I've just tried lowering it by two markers and noticed resolution in the treble range is improved, but only slightly. I'm using SED KT88s now.