Integrated Tube Amps with Subwoofer out?

I tried unsuccessfully to integrate a sub using the line outputs of my integrated tube amp when I had it. Get 2 subs and go directly from amps to powered subs. Much easier and sounds much better, bigger soundstage, clearer, tighter bass and seamless integration. You do not need a sub out as others have said previously. 

Rogue Audio Cronus Magnum integrated amps have a variable output that can be used for subwoofers. That's what I use and it's fantastic!

Black Ice Audio (formerly Jolida) has a new line of integrated all-tube amps that all feature (mono) Sub outputs.

I’m using a Line Magnetic LM805ia (not equipped with sub out) with DEBRA sub array. I have a line out conversion recommended by James (company owner). This is the same/same millercarbon mentioned. I used high quality Vishay resistors. Problem solved. 

I use the outs on my Ayon Spirit III integrated for stereo subs.  Love it.