+1 the first step is to have your bass wired for stereo. Rickenbackers have this option stock, most don't. Once you have that, use a stereo TRS cable that splits to 2 mono TS plugs, and run each to it's own amp.
I'm not going to a separate amp, but I have wired each pickup to a different socket to mix them on my pedalboard rather than passively in the bass. The '2 sockets' is kind of ghetto - going to re-do it with a 2ch cable at some point.
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