Well... guess I have to jump in the rabbit hole of speaker cables... lol

Gman74, plus 1.  Relatively inexpensive but effective power conditioner set up: Shunyata Venom Defender in simple breakerless power strip like Wiremold L10320.  Around $300 all in.  Try this on your source and preamp, not power amp.

Captbeaver, do not scrimp on source.  Can’t fix original sins.  That said, there are a number of good to great DACs that would provide more involvement than older Denon available today new at many price points.  Buy used, especially if you can live with red book to 24/192 resolution in PCM.  Lots for sale on Agon right now in many different flavors/sound signatures.  Maybe a nice used Chord DAC for you?  Use Denon 2900 as a transport, but don’t cut corners on digital cable;-)

I think and believe that knownothing has hit the nail on the head. the source is your first "crown jewel"

Tweeters are back and I just installed them... Mr. Kelly included some silver solder for the task... I REALLY need to learn more about DAC... 

https://www.us.marantz.com/us/products/pages/ProductDetails.aspx?CatId=HiFiComponents&ProductId=...

Step up or wasted move?

Check out the review below.  The Marantz SA8005 is a solid player.  I happen to own the original Arcam irDAC compared favorably to the Marantz here, at least for streaming digital.  The original irDAC plus a decent digital interconnect can probably be aquired for much less than the SA8005, and when used with your Denon would sound better on redbook CD’s or PCM digital files streamed from a computer.  There are many other high quality PCM DACs from other manufacturers coming available used for reasonable prices as people look for DSD and MQA capability (I would steer clear of the Arcam irDACII however).

https://www.wifihifi.ca/LatestNewsHeadlines/HANDS-ONREVIEW:MARANTZPM8005ANDSA8005.html