High end stereo preamps? Worth it?

Emergingsoul,
               Im not familiar with the Mac and AR preamps you mentioned above. I would seek out a online McIntosh community of owners and get their opinion on the c1100 and same for the Audio Research of community owners on their take for the ref 6se.                I’ve collected stuff throughout the yrs. I have a few of extremely well regarded preamps because I chose to pick up a few of the best picks from audiophile friends that they’ve heard.  Each one of my pre’s has its own unique character, but a thing that I have noticed that separates a reference preamp from a very good pre is the size of the presentation.  A truly reference preamp is gonna be EXTREMELY open to the point where one cannot detect its boundaries and it will throws a gigantic soundstage with great dynamics. So as you’re evaluating preamps, I would take note of its openness.  It should sound like there are no walls or boundaries to the presentation. This should not only be evaluated with loud playing or certain tracks, but most importantly the music should have absolutely no boundaries even at low level and this should be evident on all the different types music played.            

What makes them worth it? What  qualities, preferably not expressed in purely subjective terms, makes a high end preamp that?
If I were to observe that a well designed $300 DIY preamp was indistinguishable in group blind testing from a Halcro DM10, and actually measured better, what would your response be?

Is anyone aware of these types of components, and have you heard them, and are any available at a more reasonable price level?

Funny, if you are asking about an integrated amp, with a direct plug-in RIAA option, it's my current design project.   (also a direct plug in discrete headphone amp for "personal audio".  Moving slowly due to other "paying the bills" projects. On the other hand it is (targeted to be...) fully remote, in part because the approach i am taking ought to simplify the signal path down to a pair of resistors. And i want remote capability and presume others do too.

Target is ~$2500 + RIAA. Not sure if you call that reasonable. And, of course, i don't count pricing o performance chickens until they hatch. Could be a colossal dud - but the basic unit, sans remote capabilities, is floating around getting independent appraisals. SO far, so good compared to ~ $10k and up combinations.
yep simpler is (generally) better.
One caveat, as a noted above, all that assumes that the simplified system remains properly impedance matched between stages and operates within its optical range. This is not always true.
G

Ah the "great preamp vs no preamp" question.
So how can anything be better than zero distortion? Its tough, but possible in one of three ways.
1. It adds a euphonic distortion that you like.. nothing wrong with this, its what a Piano’s sounding board does.

But why turn it into something else again with more colorations, it’s not what the maker of that piano specifically wanted you to hear. "Otherwise he may of added a tube sound board🤦‍♂️" and then called it a synthesizer instead of a piano.😏

Cheers George

@itsjustme - no - I was talking about going straight from a phono stage to a power amp. Basically a one input preamp with that input being phono. Output to a power amp (not integrated). Same amount of cables as if the power amp was integrated, but eliminating the integrated's preamp switching circuitry. Sutherland's philosophy seems to be take out whatever you can in search of a straight line connection.

@lowtubes - who wouldn't value purity and tonality?