Where to go from here?

This is a hard question. From what you say, you are trying to make a huge jump…. Great idea. But if you make it too long (like years) in between the purchase of one really great component and the rest. You have a couple other mediocre components bringing the overall performance down. … years go by with a very suboptimal system.

I am not ever in favor of changes in less than 2x investment. If you want to even up the performance on all components, you have to choose from:

Streamer, DAC, Preamp, and amp.

Typically if really well chosen they should all represent roughly equal investments. The Denon is an AV box… so ideally all of its functions should be replaced.

Assuming you are OK with your amp. Then focus on streamer, DAC, and preamp. Something like a Blusound streamer (or next step up… much better), a Schiit Yggdrasil DAC, and a used high quality preamp (audiophile quality… like Audio Research, Conrad Johnson, Cary or other). The preamp really sets the tone of the system. I think you could get all these for around the upgrade cost of one piece.

This would get you a huge upgrade… and a system you could live with for years while saving up for the next level.

There are a lot of ways to do this… but I don’t like getting caught with only one spectacular piece. Although, if I did… it would be the streamer (yes, the streamer… If I was going to pick one piece I would get an Aurender N10 streamer… but then throw in a Schiit Yggdrasil DAC (because this is an outstanding streamer… I know this is counter intuitive.

Well, hopefully my point is clear… it is a system and one or more suboptimal components makes for a very sub optimal system.

As the Denon is a mid-fi AV receiver, I would look at DAC that also has a great preamp section. Otherwise you would have to worry about the extra cables you need in between and for power as well.

I may sound biased as I am an authorized dealer for T+A, but their DAC 200 is worth considering. But before I was, I compared this unit to a large range of DACs included a fully modded DirectStream, Lampizator Baltic 3 with $1K of tubes, a Mola Mola Tambaqui, Topping D90 MQA, Weiss 501, the Aurender A15’s built in DAC, and the $38,500 T+A SDV 3100 HV. The DAC 200 shares many similarities tonally with the reference SDV in terms of musicality, warmth, and detail, and it pairs a very good preamp with it (albeit only one set on unbalanced analog inputs). HDMI is an optional add-on if you need it. It’s a great unit for the price considering that won’t break the bank like the Tambaqui, and it may leave you with some money to invest in an amp, especially if you can sell the Denon and Monolith and recoup some cash there.

Thank you for the great replies. I need to keep the amp and denon for ht purpose. I plan on a digital only system so that is why i was looking at weiss and tambaqui. They both stream and have volume control. Im sure a seperate preamp is better than a dac volume but by how much when im looking at these higher cost dacs. I lose a lot of the value that a preamp offers if Im not concerned with analog. Is that right? I hear great systems at audio shows but its hard to tell if its the  DAC, amp or preamp that Is credited with what I am liking the most.

I'd suggest you look into what equipment you can use in your own home on a trial or loaner basis.  That will probably give you the clearest idea of which approach gives you the biggest improvement. 

How good is my monolith amplifier? Audioholics raved about it but stereophile shot it down saying it was dark sounding. I didnt design or manufacture it so my feelings will not be hurt if you feel its not that great. I know audioholics use denom av receivers to listen to music but im skeptical that mid priced av's ideal for 2 channel. I know first hand my speakers sounded far better plugged into the new $10-12k storm prepro at a demo. It was clear how much unrealized performance potential my have. speakers have