Is there anything other than a Benchmark DAC?

OP, you mention that you may go with Mcintosh. If it includes a built in dac give that a shot for a while. They are actually quite good, I'd image the DAC2 module would compare nicely to a lot of top rated dacs.  

There’s DAC 2.2 SE by Abbas Audio on eBay in UK right now. You can easily convert it to 110V. I’m using the model 3.1 and it is by far the best DAC I owned so far. I'm using Sound Lab speakers with Atma Sphere electronics and Missing Bond cables.

I have had a DAC3 HGC  five years now ( Dr Frieckert- Hana Umani- Sutherland Little Loco- Benchmark AHB2- Harbeth SLH5) and find it hard to think that losing any of the low noise floor is worth a switch.

i have listened to a few other high end systems in homes and at dealers and my ears just get distracted at times by the noise floor as I’m used to just zero.

That being said paired with an amp other than Benchmark and you possibly will lose a bit of that blackness.

My take is is to find the least colored reproduction I can. ( and yes there are always arguments that any combo is colored in its own way… let the cable searchers get chatting!) I personally find the DAC 3 everything I need and I like to settle into a system without the swapping fever of looking for that little change.

i had my previous system mostly unchanged for 20 years and with very minimal outside listening experiences. I find that when I go listen to a system other than mine that my ears are “ calibrated” or rather just used to a sound and that it’s easy to feel the difference in an almost magnified way. It takes time to adjust and the question I always ask is will I want to just sit and listen to this every night? Be excited to listen? The equipment should just get out of the way, be neutral. 
A few nights ago I listened to a recording I know very well but cycled though the various pressings I have mixed by different folks and having a system that just presented the music with no bias of its own was heaven to to me.

Not great input for you! Lol

But just beware the chase. 

So many great dacs mentioned here. The Abbas is one that is quite special. But outside of something along the tube Dac offerings out there - which seem to bring something exceptional to the presentation - you should look into new designs like the Harmony Laiv Dac. It’s already considered to meet or exceed the level of the Terminator 2, yet with its it own unique signature. I know it’s cheaper than others here at only $2700, but the tech associated with dacs and streamers tend to move so quickly, that it’s good to consider designs that are doing as well (or better) at a lower cost.

Another example that was mentioned here was the Okto Research Dac 8 stereo which is my current Dac. Offering this one as an example to this point, in that its SO good that I wouldn’t touch another Dac unless it was very, very unique and caused me to make a different turn in my system. It was reviewed to meet the level of dacs in the 5k range, and it was only around $1200 used. And I can attest to the its capabilities, as its attributes only become more and more apparent as I upgrade any other part of my system. 

The OP want tube. Used audio mirror troubadour dac. For second system MHDt orchid might be your ticket.