Hi, first post and I have very little, to no audio experience. My 20+ year old system is failing. My NAD 515 CD player failed and I no longer have it. My Classe' CP-35 pre-amp is cutting out, so I am no longer using it. I contacted Classe' and they said I could ship it to them in NY (I am in ID) and for $140, they would diagnose the problem and give me an estimate of how much it would cost to fix. I'm hesitant to do that with a 23 year old pre-amp. So currently, I am running a cable direct from my six year old macbook air headphone jack, to my Classe' CA-101 amp and Hales Revelation 3 speakers. I am listening to iTunes and YouTube. Question: to start to rebuild/add to what I currently have (not much), should I purchase a DAC, like a Topping D90 or SMSL M400 and/or should I repair or replace the pre-amp? Thanks