JCM 800 Series Model 1992 100 Watt Bass Amp

[W5FH]

Hello--
   I am looking for some technical commentary on the JCM 800 Series Model 1992 Bass amp, based on my study of a schematic dated 23-4-81. I am not a player but enjoy building amps for those that do. I enjoy studying the circuitry and learning.
    My curiosity is about the input stage that is warm biased (100K Ra, 820 ohm Rk) but has no cathode bypass, followed by the cold biased stage (100K Ra, 10K Rk). This seems unusual for a bass amplifier, but I do realize that tone shaping is being done in some very different manners than most amps.
Thanks all.