The Block Diagram:

14
INPUT BASS V1–V8 = 12AX7
V9–V10 = 12AU7
V11–V16 = 6550A
V1V1 V2
TREBLE
GAIN LEVEL
1+
1-
EEK! UGH!
SEND RETURN
EFFECTS
LOOP
SLAVE
OUT
IMPEDANCE
SELECTOR
SPEAKON
SPEAKER
OUTPUTS
1/4"
SPEAKER
OUTPUTS