My AA Mark II is perfectly quiet when run through my McIntosh Tebe receiver and when run through my other tubed amps. Hve tried running the AA through another amp?
If you have a really good rapport with your local high end audio shop, try bringing the AA down to them and try it on a couple of amps. Just remember, there is a skrew holding the transport in place that is meant to snap if the AA Mark II is bumped during, say, shipment. The problem is easy to repair, but might be a bummer of a new problem.