I have a 402 running subwoofers on my home stereo system, and that thing's a bulletproof beast. As bongo pointed out, there's absolutely no harm in using one side.
The variable is the pedal. Bass guitars need very high impedance inputs, and don't work well with most home stereo pre-amps. If the pedal has its own preamp and isn't a pass-thru design, you should be in good shape. Either way, the worst that can happen is you get inadequate volume or poor sound quality, so there's no penalty in experimenting provided you always start with the gains down as you change settings, and work your way up slowly.
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