I mean, if you stay out of the "I just spent $5k on a CD player, surely I should spend a couple hundred on cables!" Mentality you should be fine? I started out with a Yamaha rig that was probably a lot like your Onkyo - easy to tell it sounded a good bit better than the SLIGHTLY less expensive Sony/Pioneer stuff being sold at Best Buy circa mid-90s. I got vinyl-curious around 2001 mostly because there were some really great used record stores where I lived that were CHEAP! The whole Napster thing had exploded and I was looking for a new way to easily just listen to lots of music Id never buy on CD. That took me into an "audio salon" looking for a cheapish record player because that was about the only place you could find them back then. I was a broke grad student and there was a dude that was pretty patient with me in terms of letting me try stuff out. It didn't take long for me to realize that in terms of electronics, I noticed a pretty solid difference between my Yamaha stuff and the $1kish amps/CD players by Rega, Rotel, and the like, but the stuff beyond that point didn't seem to bring much improvement to the table unless you were in an amazing room driving amazing speakers. A couple years later I was able to get the $1k Rega amp for $300, and same for CD player. I still have the amp and it still sounds really great.
