I hate biasing!

 I check the bias of my Ref 110 every month or so. But I have not had to adjust the bias in quite a while. They are always spot on. Usually I only have to adjust the bias the first couple times after I install new tubes. After the tubes settle in the bias should not move much. If you tubes are continually drifting, there could be an issue. How many hours are on the tubes? When tubes start getting to the end of there life span, they can start drifting. 

Bifwynne,
It makes sense to me that ARC is finally offering autobias.  I have both manual and autobias tube amplifiers and certainly do not hear any sonic degradation with the autobias amplifier.  In fact it's the best sounding amplifier I've ever had. So without question autobias can be implemented quite successfully. 
Charles 

Do you have the yellow plastic tool that ARC supplies with their amps? It makes finding the slot in the trim pot so much easier than using a screw driver. Also some of ARC's amps make it easier to actually see the slot of the trim pot whereas with others it is blind. I had a VS110 and no original tool and it was a totally blind and frustrating "pin the tail on the donkey" exercise. My Ref 150SE makes it easy to see the slot and since I bought it new it came with the original tool that for some reason, again makes it easier. I suspect the shape of the blade is optimized for the slot. 

Pin the tail on the donkey is a great analogy.....I do have the yellow biasing tool....not sure how many hours are on the tubes.....in the 6-8 week intervals there is not a lot of drift but eneough that I want to use the tool to adjust. I would love the autobias aspect and if they ever offer an upgrade that brings this attribute to the Ref 75 I'd probably do it.  The Aesthetix Atlas amp does autobias but there is no dealer here and I would definately want to hear/compare it to the Ref 75 before going that way.  I have their Pandora Dac and have had the Calypso in the past and love/loved both of them.

Thanks for all of the feeback and Elizabeth its nice to see you "back in the fold".

The Asthetix Atlas has a transistor output stage so there're no output tubes to bias. The only tubes are the small signal types in the input section of this amplifier. The Atlas probably sounds different from the ARC REF 75 but not necessarily better.
Charles