Small form factor integrateds

Going back to looking for a small form factor integrated for a desktop placement of electronics running PC to USB. I know about Rega Brio, Heed Elixir and a used Bel Canto. Anyone ever compared any of these? The Bel Canto is I guess a Class D but reputed to sound excellent and high powered. It could be a multi use am which is why it made this list (plus costs about the same as the others used). Any comments on sound for these? Will be driving Spendor S3/5 on bookshelf in home office playing a wide spectrum of music. Thanks. 
How much power do you need? Tubes considered, now or future? Desktop, maybe not tubes. Efficient speakers will help you keep any amp small.

I have a small 10 wpc tube integrated, Luxman SQ-N150 in my office, far enough away so the heat is not problematic. Sounds wonderful. Line of infrared sight.

Just enough power here, I got lucky, speakers are low efficiency.

You can see my little Luxman on a bookcase here

I am using a self-powered sub, via speaker wires, so the amp does not get a break, only the speakers don't try to make low bass, helps them sound great.

I wish it had PREOUT, then I could use it's low power for only upper bass/mids/highs, a much smaller power load, out to a self-powered sub for power hungry low bass.

or a 'stereo pair' of front firing subs located so that their fundamentals and overtones which give directionality to bass.

OR, speakers you can bi-amp.

Raven Blackhawk has a built-in crossover, scroll down, they say the bass is 65% of the power load.

"High-Pass Crossover

This addition to the Avian series provides an extraordinary advantage when using a subwoofer. It frees the power amp from 65% of the load it normally has to bear. This is like tripling the power of the amplifier in terms of its ability to drive speakers. It also frees smaller speakers from reproducing low bass frequencies that they really don’t reproduce very well which lowers overall distortion. This is all achieved with a gentle 6db per octave slope making it easy to achieve a seamless transition with a good quality subwoofer.

It tempted me, but would not fit on top of my bookcase like the Luxman easily does."

Oh, I just looked at the Rega Brio, you are talking SMALL, I don't know anything about those, sorry.
U want High-end “small form” integrated amp (ergo a “small footprint”..)



Height – 73. = 2.87”
Width – 215 = 8.46”
Depth – 360 = 14.17”
Weight (kg) – 6.9



this one is hard to beat the more you look at it. Linear Tube Audio Z10e will power sensitive (above 90db) speakers, and any headphone out there. and it’s not ordinary sounding. not cheap, but won’t break the bank, sold direct. an ’end game’ product in a small form factor. it’s what i would buy if i was asking the questions you are asking.

to get user feedback i would recommend visiting a serious headphone forum such as;

or read the Herb Reichert stereophile review.
nuprime’s ida-8 is outstanding as a high value unit... very good sound, built in dac that is very sweet, excellent amp section, powerful and full tone - they did a great job on this one

no affiliation, other than having one :)
I would check out the i7-XR and i9-XR from Cyrus.  Pricier than the Rega but MUCH better amplfication.  They have a very good built in DAC and a solid phono stage. $3799 and $4499 respectively.  Cyrus has a variety of other half-width units that are pretty darn good but these are the gems of the line.  

Yes, I am a Cyrus dealer so I am biased but I think worth a glance.  

Check out Fosi amps on Amazon perhaps before automatically dropping more $$$s.  Little to lose.  I have one in one of my systems and it is a big time overperformer for the price.   Drives kef ls50s nicely which is not a particularly easy task and sounds very good.   Also have Bel Canto c5i which is a wonderful device as well. 
I always wanted to try Parasound slim line products. They have a new "New Classic 200" that might fill the bill. 
NAIM Atom…i am biased as i own one…..

Can grow with a system of excellent components as streamer and preamp…

have fun, enjoy !,,,
McIntosh MA252. I recently picked one up and it’s wonderful - compact and has more than enough power. If you are looking for tube sound I would also take a look at the rogue, raven, and primaluna offerings, all fairly compact but I believe all larger than the Mac, overall sound wise I found the McIntosh to work best for me. 

I have 2 Benchmark AHB2 (12 inches wide) and a Topping pre90 and Topping D90se stuffed into an IKEA toy shelf. I use this system because it has as tiny form factor, it is super neutral, and sounds good. The Spendor's I have heard in the past were a little warm so I think this gear would sound good with it.