Number of Channels
Number of channels counts the independent audio signal paths a unit amplifies or processes.
One channel is mono and two channels support stereo. Channel count is separate from the number of input sockets, output connectors or processing bands.
Number of Channels — Power Amp
For a power amplifier, the count describes its independent amplification channels. A monoblock has one channel; a stereo amplifier has two, even if those channels can also be configured together for bridged mono operation.
Compare the channel count with the speakers or drive arrangement to be powered. Extra speaker-terminal pairs do not necessarily provide extra independent channels. Keep bridged operation and its load requirements separate from the amplifier’s normal channel count, and do not count a pair of separate monoblocks as two channels inside each unit.
Number of Channels — Equalizer
For an equalizer, the count describes independent mono or stereo signal paths that can be processed. A stereo unit can process left and right signals; linking their controls does not turn the signal paths into one channel.
Compare the number of signal paths with the system layout and check whether controls can operate independently or together. The number of frequency bands per channel is a different specification. Multiple input connectors can provide alternatives for the same channels rather than additional processing paths.