Mo, I think you're looking at the 101b manual. From the Bogner website:
20th Anniversary option:
This option features a new preamp circuit with so called boutique capacitors which have been available for the past few years now. The pre EQ’s 2&3 have been shifted and a vintage modern style switch lets you decide the overall flavor of Ch.2 and Ch.3, bypassed when in plexi mode.
The plexi channel has slightly more gain and a foot controllable boost was added which expands the amp to have 6 sounds on tap. The boost is engaged with the same switch as for Ch.2 & 3.
The clean channel has been changed; special emphasis was taken to the boosted mode which gives you more gain with nice balanced frequencies and compression.
Power amp dampening was adjusted to compliment the new pre amp design, the Excursion switches so to speak. The amp was designed and comes standard with 6L6 power amp tubes. The 20tA has a plexi panel with gold background and is housed in a slightly bigger head shell to feature the all familiar classic vintage vibe.