the unit uses 1 12UA7, and 18 of the 6922s. i'd confirm that the tubes spec'd are in there, that you have the problem regardless of source selected, and also if you have it on both RCA and XLR outputs.
the einstein doesn't have volume steps; its a continuous attenuator (not a ladder or shunt)
the einstein doesn't have volume steps; its a continuous attenuator (not a ladder or shunt)