It could be 8 & 4
or 16 & 8.
Regardless of which outputs it left the factory with, you can change it to whichever best suits your needs. The output transformers on the old Sunns have 16, 8, and 4 ohms taps. Two of them (most likely dependent on what cabinets the particular head was sold with) are wired to the output jacks, but are easily switched if need be. The output jack are wired in parallel, and when used together will default to the lower of the two impedances. In other words, if the jacks are wired to the 8 and 4 ohm taps, when used individually they will go to the respective OT tap. If you plug into both of them,
both jacks will go to the 4 ohm tap, so you could plug in a pair of 8 ohm cabinets.
If you aren't sure which way the output jacks are wired, the
only way to know for sure is to
open it up and look. Just because one studio PA head may be wired 8 & 16 does
not mean yours is.
the labeling on mine is clearly an original factory label, not something a previous owner wrote on it. if you want to be sure, get a DMM and check the output.
I'm not exactly sure how
that works
, but I'm thinking your best bet is to pull the chassis and physically check which taps are actually connected. While you are in there, you might want to change the electrolytic filter caps. I guess they
could still be OK, but if they’re original, it’s
extremely unlikely.