Click on the hyperlinks to the left to see the pre-amplifiers and amplifiers.  Not all the components are illustrated.  The majority of Pioneer's amplifiers were integrated, as can be seen below.  

Pre-Amps (1975-1980)

SPEC-1
C-21

Power Amps (1975-1980)

M-22
SPEC-2
SPEC-4

Integrated Amps (1975-1980)

SA-5500II
SA-5800
SA-6500
SA-6500II
SA-6800
SA-7500
SA-7500II
SA-7800
SA-8500
SA-8500II
SA-8800
SA-9500
SA-9500II
SA-9800
SA-9900