Poking around various Ampeg product manuals, I noticed that the PF-350 head has the Treble control centered at 8 kHz, while all the other PF heads, SVT Heritage and SVT-7Pro heads, and the Classic, Scrambler, and SCR-DI pedals have a Treble frequency of 4 kHz (the SVT-3Pro and SVT-4Pro list 5 kHz). Additionally, various products show slightly different specs for the Ultra Low setting and widely varying amounts of cut and boost on the EQs. These kinds of differences extend to the PF heads, too, which I find puzzling, given how similar the products are otherwise. So I'm wondering: First, why does the PF-350 have a treble frequency that's so different from all the other Ampeg products? Second, does Ampeg really spec similar products that differently from one another, or could typos in the manuals be involved?