Polarity of N1200/N7000 Terminals

[karlabecker]

I have a pair of N2600s and a pair of N7000s. The input polarity is obvious (Red & Black - R/B) the HF and LF output posts are just numbered 1,2,3,4. What are the polarities of these terminals. I know 1 & 2 go together and 3 & 4, of course, but which ones are Red (+) and which are Black (-)? Thanks, much.

[1audiohack]

The center two, #2 & 3 are common to the - terminal of the source.