the green caps signify pas3, early pas3 used the brass faceplates of the pas2 era , and
there was an option from Dynaco for the new silver face. Pas2/3 distinction is
with the green caps not the color of the face plates.
otherwise you would see PAS3 with the silver faceplates and NO green caps if they
were that interchangeable. (if you do then the faceplate was replaced but see below)
Another one of those telefunken smooth plate 12ax7, and cloth covered transformer
leads myths created by consensus.
back about 30-35 years ago, there was a rash of changes to these PAS units
, changing out the switch mechanism ruining the separate phono and line level
ground systems for the new look, and several "bootleg" back panel labels
with various PAS, PAS2, PAS3 designations.
at that time, I traded my collection of TAS for a pair of PASs, and noticed the only difference
was the green caps and asked the original owner who informed me of the differences and
told me about the silver faceplate option. Since I joined eBay in the early days, I would
download the pictures of any PAS being sold, and they continue to confirm that green
caps were the transition from PAS 2 to 3, the brass units shells being emptied out
of inventory independently.
Faceplate options come up in eBay and other places. I have seen the one in black I
or white and I think it's the best option since the silver ones get beat up (easily). If I kept them,
I'd refinish the brass (because it's engraved) with black powder coat, and fill in
the engraving with red.
As far as I have seen through the decades, aside from the X designation, there's
no one else who IDs these by the green caps.
I would love to see an original one owner PAS with original silver face plate without the
green caps but with provenance. You're talking about someone who bought their PAS
in the 1970's since David Hafler left/sold dynaco and started Hafler in the early 80s'.
back in those days, you could pickup dynaco tube equipment for chump change.
and people knew what sold so the silver faces were "sought after"
(flipper top ten phrase) and lots of stuff was "re-manufactured". If you ever see
a brass PAS with blue LED, it was one of several I sold on eBay. Sampling
one or two and drawing conclusions makes it dicey to generalize.
Not trying to change the myth system but trying to change the path of the stampede.