How much should I spend on a new DAC

Thank you everyone for your comments. I will probably pull the trigger on the TEAC UD-701N next week. It have 4 linear power supplies, Two for the left and right channel for the analog output, one for the network module (streamer) and one for the digital module. It also have analog preamplification stage and headphones amplifier. Its like 4 separates packed in one box.  The greatest thing is that they use absolutely the same DAC, preamp and headphone module as from their high-end Esoteric N05-XD. If anyone is interested I've created separate thread on audiphilestyle forums. https://audiophilestyle.com/forums/topic/67406-teac-ud-701n-undiscovered-gem-or-farce

I have never heard the  DAC.  However I have no trouble imagining, based upon my experience with Pro Ject gear, that it doesn’t begin to hold a candle to the rest of your very capable system.  I think you might find that a DAC upgrade is a significant, major improvement. As another poster indicated the biggest improvements in DACs is going from $1k to $5K.  Streamers matter as well, though the DAC is more important.  Yes, you can get good sound from a PC, but even a $500 streamer will clear up some audible PC issues and will be easier to use.

If I was interested in an excellent standalone budget DAC, this would be the one that I would choose (or try, with their 30 day audition) which Steven Stone rates very highly. For more money, I would probably consider the Holo Spring 3 KTE, the Denafrips Pontus 2,or the Schiit Yggdrasil (not sure which variation). 

Topping

I have the Musician Pegasus and its by far and away the best Dac I've owned. I think its around 3k (got it in a trade).

I'm sure there are lotsa good ones but I've always played in the 1-1.5k area and this ones a lot better. 

I much prefer this pov: how little can I spend and still be happy with the SQ (obviously no DAC is going to "fix" any other problems in my system, including the room)?  With current trends re: (mostly far east) DACs, I feel there's a change in price:performance. As such I'm focusing on a detailed, neutral performance from a DAC and getting the rest of what I want, downstream (processor and speakers - mine are all Active). There are some people who feel strongly that the more you pay for a DAC the better it is; I don't think that's true any more (certainly not from a price:benefit pov). I'm using Qobuz and have only found one MQA album there, so that's not a big deal; if it were, I'd probably investigate DACs that used separate processors to programmatically address that process.

This is ongoing for me, right now; I've got two DACs I'm looking at, and a third is on the way; I'll end up with one for the main system and a second for my PC. I've rejected the Bluesound Node (good reminder to myself to sell it) because of its analog output (my processor has a digital input limit of 24/96 and it would cost me approx. $4k to open that up, so I'll always use the analog out from a DAC) and software.

IIWM I'd start at the lower/middle ends of the newer well-reviewed DACs; pick your two best, return the lesser and see if the remaining one sounds/feels great - if not, use that as a base for the next product you'll test. For me it's like not letting perfect be the enemy of good.  Best of luck.