I adore my Soekris dac1541 DAC/amp combo.
While it is integrated and has a very decent built in amplifier, I do feed its differential balanced output into a Mjölnir Audio’s Pure BiPolar* balanced headphone amp.
The only other amp that approaches the insane gain of the BiPolar is another very high bias solid state amp, the Pass Labs’ own headphone amp.
I’m driving a set of LCD-4 with the fully balaned end to end Dac/Amp one/two punch and I can say i’ll be able to listen to this system end of my days to these and never be disappointed.
* Mjölnir Audio is a one man botique amplifier maker out of Iceland and not to be confused with the model of headphone amplifier also named Mjölnir produced by Schiit. (That is like confusing a McLaren with a nice but consumer level sports car!)