Hi
You may exercise mods on products with no warranty.
I thank you for your advices. I posted on the weekend I will call Krell today and find out whats up with the amplifier. It was just made in 2000 maybe I have more time on the warrantee.
I will do the upgrade not because I dont like the sound but to keep it up to date. I hate falling behind to the point where it is not upgradeable.