Weight as an indicator of quality is a dangerous proposition, doubly so in a surround processor that doesn't have internal amps (or the associated high-current demands that lead to big power supplies and big heat sinks). What does a printed circuit board with DSP chip weigh? What does an HDMI board or video processor board weigh? What does an analog audio board weigh? None of these weigh much, and their power demands are really rather modest. In theory, a good surround processor could actually be pretty lightweight.