What tube amp for Harbeth 40.1

I am looking for a tube amp for Harbeth 40.1.  I know many suggest SS amp such as Accuphase, Luxman, Hegel, McIntosh ... etc for Harbeth, but I decided to keep it with tube.  I also don’t think I need a lot of power.  I currently have a 8W custom built 300B and had a 18W Almarro 318B, and to me, they sound fine.  However, I think more power will help, and I never know what I missed until I try it out.  Having said that, I don’t think I need crazy power.  Anything 30-80W is good enough for me.  I am 3m away from the speakers, listen to Jazz at avg 83dB.

i have the following short list:
1) PrimaLuna Evo 400 integrated
2) Leben CS600X 
3) Linear Tube Audio Z40

Which one do people like with Harbeth?  Any other suggestion?

Among all qualities, I value holographic presentation the most.  I really like the feeling as if the singer is floating in front of me, if you know what I mean.  And my current 300B do pretty well in this regards, and I read this is what SET amps are good at.  Will I be disappointed with the above?
I’m not sure about the 40.1, but the newer models, the 40.2 Anniversary and 40.3 XD have an impedance curve that runs about 8 ohms and higher and rarely dips below that, so a pretty easy speaker to drive.  Your only question would be how loud you want it to go which is based on your room, listening position, music you listen to and your preferences.  
Any Harbeth that I have owned sounded great with Quicksilver amps!!

Hey yogiboy, good to know. Several colleagues with QS and others with Harbeths but not together. Which of the QS amps have you tried with Harbeth 40.1 or 40.2 speakers (if any) and and had good luck? And, stock or upgraded tubes used?  Thanks in advance for your reply. 
I have the QS Silver 70 that I have used with the M30.1, C7 and P3esr. This is the amp that I have! BTW, I use KT88 type tubes!!