Need help ! Looking for a low cost integrated tube amp for my office


Looking to upgrade my office system
Music playing through my computer to an Audio engine D1 DAC
At present an old NAD receiver playing to four Vienna acoustics Haydn Grand book shelf speakers and a velodyne sub
Thought I would try my first experience with a tube integrated amp 
Any suggestions ?
fullerco
Post removed 
I'm using a Mystere IA-11 integrated amp w/ 40 wpc. It is meticulously built by sister company Primaluna and is on sale at Up Scale Audio. It uses high quality parts and even a ladder resistor volume control instead of a potentiometer. Sound is clean and articulate w/ tight bass, tubey midrange, and extended highs.

http://www.mystere-eu.com/usermanuals/mystere_manual_ia11.pdf
Would you want to power all 4 speakers and the sub with the integrated? If so, you're going to be hard pressed to find a low cost tube integrated with more than two sets of binding posts, much less a sub out. Have you checked into an upgraded NAD?
sub has its own amp, thought this could be my tube opportunity. Would like to have all four working.  
Using a tube amp with 2 pairs of 4 ohm speakers is not an option!
 Specifications
  • Impedance: 4 Ohms
  • Frequency Response: 42-20,000 Hz
  • Sensitivity: 89 dB
  • Recommended Amplifiers Drive Units: 25-180 watts RMS
  • 5” Bass/Midrange Driver: X3P Cone, Transparent
  • 1 ” Dome-Tweeter: Hand-coated VA Silk Dome
  • Bass System: Bass Reflex, Front Ported
  • Bass Function: Impulse Optimizing QB 3 (Quasi-Butterworth)
  • Crossover Components: MKP Capacitors 1% Tolerance
  • Coils 0,7% tolerance, Exclusively Air Coils
  • Metal Film Resistors, 1% tolerance, Inductance Free
  • Crossover Function: 2-way, 6 dB and 12 dB Bessel
  • Weight per Pair: 44 lb / 20 kg
  • Dimension (W x H x D) inches: 6.85 x 14.2 x 10.4“
  • Dimension (W x H x D) mm: 174 x 361 x 265 mm


Sounds like from your post you are looking for something affordable to pair with those speakers. I can say Jolida and Cayin both have some great sounding integrated amps for good prices especially used. 
Wanna spend more the Octave V110SE I heard recently was pretty damn awesome. 
Call Dave Thomson at Raven Audio.  Check out their website.  Outstanding integrated amp for anyones budget.   Superior Customer Satisfaction and some of the most classic tubes around.  
If low cost is what you are looking for Steve Guttenberg did a review of this inexpensive tube amp

https://youtu.be/vCk12xzivp8
@yogiboy exactly. No inexpensive tube amp is going to do that. I can't even remember the last time I saw one with more than two sets of binding posts. The OP it's better off with a good solid state receiver oh, like the NAD he has but newer. 
Yes, a used NAD 356BEE could be found for under $400. Has 2 sets of speaker outputs and an extra set of pre outs. One could set up 4 channels for the 4 Haydns.
If your NAD has “pre in” jacks, I’d get a Schiit Freya+ preamp and get my tube experience that way and upgrade amp later if you want.  Or a used Freya and Vidar would be a nice pairing for not much $.  For an integrated you’re probably best off with a hybrid like a used Rogue Sphinx, Peachtree, etc.  Best of luck. 
Thank you everyone Great info !