It is possible I am mistaken here but to be exact my Atma-sphere amps are Ma1 Mk 2 Silver edition upgraded at the factory with power supply boost and Caddack resistor package. I thought the upgrade brought the amps to mk 3 status as well except for the auto bias which I really had no interest in having. BTW the improvement is much more that subtle after the upgrades and tube life and reliability has been improved beyond what I thought possible. I use to drive stats with the amps and they sounded great but the difficult load caused what I would term premature tube failure. Once the mods were completed I had no tube failure even when driving the same stats. It has been about 1.5 years since the upgrade and I have not had to replace a tube. The load with the Acapella speakers is much more benign.
