Yep, rather important network, coupling channel signals to processing.
Your choice. 2 six pins (4606) or one 12 pin (4612). Many production runs used 2 six pin (4606). As much as there are three possible channels on both H and E inputs, a 4606 rather separates the two amplifier boards, and perhaps a few cents difference in production, and / or availability of 4612 vrs 4606 during production. I personally think I'd opt for the 4612 ... but it won't make a quantum's difference in operation. I wouldn't attempt to use any form of discrete components, because of added capacitance, etc potentially affecting the time response, though virtually all of the filtering is done, in red, on the amplifier boards.
Mike
