Connecting sub to stereo system?

Hello.
#1. Passive TVC> Sub low in> Sub out> to mono-blocks>Speakers
#2. Passive TVC> 1 pre-out to mono-blocks and 1 pre-out to the sub.

#2. If your preamp is better sounding than sub (overall sound quality) and if you using full range speakers.

#1. If your sub is better sounding and if, you are using limited frequencies speakers (book shelf speakers).

My two cents :]

Thanks for that.

Cheers

The second of the two preferred IF at all possible (i.e., if your source can "drive" two amps, the main & the sub). If not, go the other way.
You'll be bale to tell if it's working through the low frequency energy -- if there's little ("no bass") then you;re not driving both amps in parallel.