yeah there are 2 versions of the af8 , the early one has spdif and the later one had adat and different converters (like the early/late version of the af12) . and the last thing i need is more pre's .

from the echo website faq

AUDIOFIRE 8 - CS4272
AUDIOFIRE 8A (NEWER MODEL W/ ADAT) - AK4620B

the problem with getting an af8 2nd hand is 90% of them seem to be early versions , I don't think many 8A versions were made