AtmaSphere Upgrade from Mk 3.1 to Mk 3.3

@

The update causes blacker backgrounds with a smoother and more detailed presentation. The new Constant Current Source (CCS) has nearly 2 orders of magnitude greater performance- and results in greater differential effect in the voltage amplifier. All the updates from the Mk3.2 level are included in the Mk3.3 level; the Mk3.2 has measurably lower IM distortion, which is audible as smoother sound.

There is a member who picked up a set of MA-1 Silver Editions and had them updated to Mk3.3. They were previously at the Mk3.1 level, so his comments are exactly about what you are asking:

https://forum.audiogon.com/discussions/atma-sphere-updates