I need a good Preamp


My current system:
Preamp:           MAC C2300
Amps:              Krell FPB 350mcx mono blocks
Speakers:        B+W 801 Series II

My MAC C2300 just quit working and really I need it in another room to pair with a MAC MC452 once it gets repaired. So, I need suggestions on what will mate up well with my Krells? I would like to spend $8k or less but I would consider going higher. I am thinking a line stage even though I did use the phono on the MAC some. I plan to add a phono amp to my system later. I just play cds with this system. Reading on this forum I sort of lean towards a used ARC 5SE or maybe a Cary SLP05 but I am open to suggestions. There are no audio shops close to me so I will be buying without getting to demo anything. I'm not too knowledgeable on stereo gear so I need some help. Thanks for the responses.
wemfan
Audio Research Ref 6 has rave reviews and is everything they say and more.  I own one and have no inclination to change.  Yes tubes rule.  
jmacs7 has the right idea, I heard the Sachs SP14 pre in my system and the clarity is really something I have not heard before. Also, read the reviews and you will see I'm not the only one who hears this openness and transparency from top to bottom. My understanding is that Don is also a really great guy but I haven't talked or dealt with him myself. 
besides a good amp, you might need a converter to encode and enhance your music files, I use audio converter to help me transcode apple music to mp3 files, take a look. https://www.drmare.com/m4v-converter-for-mac/