Best Integrated that you've heard under $5k

I have 2 - 22wpc integrated amps that I switch in and out of my main system , they easily drive floorstanders that are 97.5 db sensitivity and 6 ohm impedance

I’ve never seen an integrated amp or a preamp that was connected to a source component via optical cable vs XLR or RCA interconnects.

I believe the H390 is very close to $6k.

'street price' is right around 5 grand - i bought mine new from a dealer last fall for just under that

Raven Blackhawk

I have the Raven Nighthawk for my Heresy IVs.  Already received some nice NOS tubes from Dave.  Best I’ve had or heard.    

Focusing only on the amp or prioritizing the amp without regard to the rest of the system, as if the amplifier is the key to a good system, is a beginners mistake. 

Linn always advised one to focus on the source:  get the best source you can: put the bulk of your time and money into your source. The recording quality comes first in this. A poorly recorded LP, or dirty [well recorded] LP is going to sound bad no matter what the system. In fact the better the system the more you will be hearing the flaws upstream. The LP or CD player or system and its synergy comes second.  A bad turntable support is going to 'make bad' a great turntable [support isnt an issue with CD gear]. The preamplifier quality is next in the 'Linn' hierachy. Next is matching the amp and speakers. Great speakers cant make a bad amp sound good.  Oh well.