How do I play YouTube music from my IMac thru my Conrad-Johnson amps?

Hi guys and gals... How do I make this work?  I’m asking you knowledgeable people here rather than going to my local Hi-Fi shop where they will try to sell me more expensive gear to make this work.  I invested more than $20,000 on my system about 15 ago and I really don’t want to spend $1000’s more if I don’t have to.  I just want to be able to play all the great music from YouTube thru my great amps and speakers.  I’m tired of most of my CD’s and my Sim Audio CD player quit working several years ago and they tell me it needs a new transport so my expensive system has been sitting idol for years and is just taking up space in my tiny downtown apartment. Any advise would be greatly appreciated.  Thanks in advance :). Gordon