Integrated Tube Amps with Subwoofer out?


I’ve only seen subwoofer outputs on a couple of integrated tube amps (Rogers & Rogue) why is this so uncommon and are there any others I should be looking at? 
The Rogue Cronus Magnum III has a phono stage too, which make me like it even more. 
valjean246o1
If you do go with speaker level output from the amp to the subwoofer the Raven Audio tube amps have an interesting feature, a pair of speaker outputs with a selectable high-pass crossover at 80Hz or 100Hz that means those bass frequencies are removed from the amplifier section and passed off to the subwoofer, effectively make the amp 2 to 3 times more powerful, according to Raven. My Blackhawk was built before that feature was added so I can’t testify to its effectiveness. When I had an HSU subwoofer the high-level outputs were what were strongly recommended by Dr. Hsu.
+1 on all comments above. I have compared my sub from a pre-out on the preamp to the outs coming via the speaker terminals on the amp. It is far superior when it comes from the speaker terminals. Here's a helpful video (short): https://www.youtube.com/watch?v=bnQOjCuoR9k&ab_channel=RELAcoustics
Raven Audio tube amps 

Thanks for the tip on Raven, it looks like these are made about an hour from where I live and I love that!

DOH!!! I'm so sorry I misread this as an ask for a Tube PRE.

My bad.  The Luxman LX-380 will fit the bill, and let you put a cap in to use as a high pass filter.
This is a non-issue. There’s two simple solutions. Easiest is a LOC or Line Out Converter. Next easiest is to modify your integrated. The mod costs about $2 total for 4 resistors and can be seen in its entirety here.
https://systems.audiogon.com/systems/8367 Look at #26 of 47. That’s a close-up of the 2 resistors.

All you are doing is adding one 10k resistor to drop the voltage, and another about 1k to provide input impedance to your sub. The complete circuit diagram with explanation is here. https://www.epanorama.net/circuits/speaker_to_line.html

If you buy a LOC that’s all it is, two RCA connected to 4 resistors just like the circuit above. The LOC is cheap and easy but looks tacky. The mod is a little bit more difficult but looks factory original. Same result either way. So if you buy a LOC don’t waste your money, just get the cheap one from Parts Express for around $10.

The Raven is of course totally the way to go, and will be better in every way. Their sub out is even switchable. Check it out.