5150 Models

5150 history and changes

The only differences in the amps are these:
The pots changed in look, still all made by CTS. This happened within the first few years.
The power amp circuit board layout changed in the 5150II after it was out a couple years.
The 5150 started using that same power amp board just before it became the 6505.
The manufacturer of the output transformer changed at some point after it became the 6505. Peavey always used this manufacturer for the power transformer and for the XXX/JSX amps, but used a different manufacturer for the 5150 output transformer. The early 5150 did not have a different transformer than the later signature amps as some people have claimed online.
The ribbon cables were changed recently to a heavier duty thicker wire instead of a flat ribbon cable.
Main difference, different tube suppliers thru the years.
 

Head vs. Combo

5150 vs. 5150II

5150/6505 Signal Path

clean, crunch, and lead channels all go:

V3 is for the loop
V4 is the PI

5150II/6505+ Signal Path

clean and crunch channels

V3 is for the loop
V4 is the PI