As mentions by others herein, $2000 would make for a great improvement over use of a iphone with a purchase of a streamer/DAC. You will get a greater return on your investment in the amp and speakers.
What next?
I have restored a Marantz PM94 and have recently purchased a pair of Von Schweikert VR4.5 speakers, am using Apple Music through my iPhone. What would be recommended to improve the sounds? Also have a restored Sansui 9090DB with stacked Advent speakers. Just read on the forum about the value of preamps and wondering if I should be looking at a tube preamp to add to my systems? Am retired so not looking to spend big bucks. Thanks in advance for suggestions.