Looking For A New Tube Integrated Amp With Very Specific Features

@freediver 

Check out the Audio Research GSi75

I had one for a couple years and it was fantastic.  My Wilson Sophias needed a stronger amp.  I have a very large space and often play at very loud volumes when I am cleaning the house or cooking so as long as you have reasonable efficient speakers it would be great.

Perhaps enlist a competent builder to create a custom rig. Chances are you will get the one you want for much less than all the aforementioned. Also you will be able to source some of the stuff and aesthetic to your liking. 

A CA SET or especially a point to point SEP points me you have sensitive speakers, and will not cost you mid four figures and above (not even close), and is a minimalist approach to audio. 

Your "REALLY want" part of the list may need to take a backseat to a truly competent if not magical circuit.

For me, I run a custom 6BQ5 (EL 84)/ECC 83 SEP in dual mono Class A mode to Audio Notes. The circuit is nice. Transformers decent. Not a 5 or 6 figure AN mind you, but "good enough".

I do not have a sealed chamber audio room these days, not a "lean in" listener any longer, and like to drop a needle on an OG LP, and lean back and enjoy.

Having two independent volume pots also lets me fine tune for our normal actually lived-in room with all kinds of cool stuff we have collected through the years (and thus reflections.) 

How much did I pay for it? Let's say the Valvo (Phillips Mini Watt branded) DX McP ECC 83 and D plate1955 Herween origin EL84s also labeled Mini Watt that I pulled out of an old BX Noreclo radio we had upstairs would cost more on the open market. 

FWIW, I also believe that your AC power source is going to be mucho importante, balanced inputs or not. 

Humbly.

@freediver you haven't specified if you want a differential balanced amplifier or just balanced inputs and outputs.  

You could have said "long tailed pair".

@faustuss Yes, I could, but FWIW that term is considered outdated by a few decades, although I still see it used from time to time. Its often used to refer to a driver circuit in an amplifier, and as such while it does describe a differential amplifier, the kind that are used in amps that use that description usually are not high performance.

A good differential amplifier will have a constant current source (CCS) in its cathode circuit, which improves the differential effect dramatically. A 'long tail pair' generally will not have a CCS and may have slightly different plate resistor values as well. The plate values are slightly different to compensate for the mu of the tube type and the fact that only one input of the differential amplifier is being driven. These things are done to achieve a symmetrical output. 

When a CCS circuit is present then the plate resistors can be the same value. 

As many of the suggestions do not have remote volume control, I am offering a stand-alone remote volume control that will work with just about any amp. You can see it on my Instagram channel… worksbau.