Two-channel sub connection options


I apologize if this isn’t a very high-end question, but perhaps my ignorance will amuse you.

I recently retired the full-range speakers I’ve been using with my Integrated Amp and replaced them with some smaller speakers which will require a subwoofer. For want of a LFE output on the amp it appears that I’m obliged to run speaker cables from its System B outputs to the High Level inputs on the sub.

Question #1: Does that mean that some substantial fraction of my two-channel amp’s power will be diverted to the sub, bypassing the subwoofer’s own internal amplifier?

Question #2:  If I simply need a two-channel line-level signal for the sub that is subject to the same volume control as my primary speakers, could I not use the headphone jack on the amp (which has no separate volume control) and run a 1/4" Phone Male to Two RCA Male Cable to the sub’s RCA inputs?

If both of these options are possible, which is preferable?


128x128zoltar93
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That makes perfectly good sense - I just couldn't find it explained elsewhere,

I  have a SPL mater I used to balance my HT system.   

Thanks for your help.
If a REL sub is used as most people prefer (high level from a power amp speaker output), the amp "sees" a 100,000 ohm burden, which is a lot like nothing at all. I use 2 RELs on the same power amp with the main speakers on the same output…works very well…(resulting in a 50,000 ohm load maybe) both RELs sum the stereo mix as one of the subs is stuck in a window for deck sound occasionally. This allows the main speakers to work as designed, which could be better than shelving the bass with a crossover as, again, they likely weren't voiced for that…but can still sound fine I suppose. I don't bother with an SPL meter for the RELs to match the mains somehow, as they are turned up and down a bit relative to my taste, the amount of bass energy in a recording, how much Irish whisky I've consumed, and if my wife can be compelled to dance with me. 
Those strike me as perfectly legitimate criteria for setting your preferred bass level.