I read one review of the older model that mentioned a 60 cycle hum when the gain was turned up past a certain point. Is that any cleaner with the new version?I am SO glad that you asked! The original review done in Vintage Guitar magazine led me to completely redesign the Warmenfat's internal power supply's. The Series TWO now has fully regulated low noise D.C. tube filament power, The series 1 uses A.C. filament ( Like most vintage guitar amplifiers did. ) The B+ and B- supply's have now been fully regulated too. The P.C. board grounding has been re routed to further eliminate noise. The hum is totally gone.
Other ( Major!) improvements include the newly redesigned output transformer. A new winding has been added to provide a truly balanced output that can provide an output of up to 25 dBm into a 600 ohm load. This can be turned down to a lesser level using the post gain control. The series 1 had an unbalanced output and could not drive the digi design ( Pro Tools) converters to maximum clipping level of 19 dBu . The original un balanced output is still there too, it is in the white RCA jack. The red rca jack is a direct output that produces a constant output level that is independent of the pre and post gain controls. I can go on all day long when it comes to talking about tone!
For more information on the differences between the series one and two, see the comparison in the link bar above.