Tango Controller - Fixed Output?

Your 'B' is not a zone output, but rather a source output to cascade to a second tango unit - or line level pass through for the source (not zone) 8 audio to some other device. The audio outputs shown in the 'B' section of your diagram are simply to pass the signal of the corresponding input.

Do you have something plugged into source input 8? If so, that should be what you hear coming out if your 'B' output 8.

To further clarify, if you had a 16 zone system, you would plug your sources into the inputs 1-8 of the first tango. Rather than use a y-splitter to feed the second tango unit, your would run rca cables from the OUTPUT -- your 'B' -- to the corresponding source INPUT on the second Tango unit.

If you are looking to take the zone output of the Tango and convert that to line level to input into a local receiver, you would want the line level converter: http://www.amx.com/products/DAS-LLC.asp

This is common for a system that has a tango feeding the whole house distributed audio and where one room is a local 5.1 system and you want the house feed as one of the source inputs into your local receiver. You should be able to set the volume output for the particular zone output to a fixed level.