Primaluna EVO 400 Amps/Preamp lacking bass impact

all tube amplifiers will have a low damping factorel34s don't have the current delivery of a kt88 or 6550

adding a sub is not the answer a good sub adds pressure to the leading and trailing notes of the mains 

you have a few options tube roll or add a solid state amplifier

we are a focal dealer if that helps

Dave and Troy

audio intellect nj

Focal dealer

or upgrade to a tune amplifier with balls or a hybrid

If the subs are set correctly they don't get in the way of the mains.

It's all in the setup.

I have never been disappointed in my smaller EVO 100 integrated for sustained bass like organ,Tuba, or the punch of a large drum.

What I have noticed is a significant increase in lower bass notes, and attack with JJKT77 outputs. I do not need a sub with my speakers in the current room.

@kennyc 

Maybe a tad of both, mostly a bit more bass energy; Is it okay to run the Kanta no3 on 4 ohm tap of amp?

Yes.  Primaluna recommends trying the different taps to hear which one works best.  I use the 4 ohm taps on my Kantas.