Pre-amp dependent amp hum - is this normal?

[Neuronal]

they are two wire plugs; each sub has a line-level and speaker level input, but it would be really hard physically for me to navigate an RCA cable to these guys, whereas hopping off the speaker is easy.

I saw in another thread about someone with a stereomour and a subwoofer hum that you had recommended trying taking the speaker wire connecting the main speaker and the sub, putting an RCA jack at one end with the black going to the outer shield, and then using the line-level inputs rather than the speaker inputs; would that possibly help here?

[Neuronal]

So I went ahead and made a wire that hooks into the speaker terminals on one end, and terminates RCA on the other (with black to shield), which I fed into the subwoofer and...voila, the noise is gone. The sub is a little louder than before, but not by so much I can't manage it with the volume control. Any reason I shouldn't wire it up like this? I assume the impedance the Paramount sees in this configuration is still very high, and therefore doesn't matter in terms of the load being borne by the Paramount, but I could be mistaken so I thought I'd ask....

[Paul Birkeland]

If it works, go for it!  I have no idea what prompted me to recommend that before, but now that it has worked twice I'll be sure to remember that.  I would recommend going back into your Paramounts and reconnecting the safety ground buss when you have time.