Outboard Dac for Bluesound Nano

I'm no dedicated DAC expert. As a matter of fact I have only owned one. But...

I do have a BlueSound Node (N130) which is basically the same streamer section you have. I upgraded the Node with an LHY LPS.

I use a Black Ice Tube DAC $899  and I love it. You'll need some nice NOS tubes to make the DAC shine. (DAC is sold out atm, so perhaps this is all moot unless you are not in a rush)

Add a DH Labs USB cable and later add a Teddy Pardo power supply (LHY doesn't seen to have one for Nano yet).

I compare this to an analogue source at more than 10x the cost and it is very satisfying, exclusively streaming, via Qobuz and SXM.  

I’ve got the Nano with an Ifi power supply. The DAC I use is the Soekris 1421 ($750) and I am very pleased. A beefed up power cable to the Soekris really made a difference. I also use a DH Labs SPDIF cable ($275)  and a preamp in the mix improves things for sure.

Apologies I missed you already have an upgraded power supply 

Bump your budget up to $2,000 and get a Denafrips Pontus 15th DAC, which is the equivalent of a Venus 12th DAC. It is one of the most enjoyable DACs anywhere under $3,000

I would check out the Heed Abacus. Not popular around here, but very musical and satisfying. Check out the reviews. Gene Rubin is a dealer and his service is outstanding. If you have a problem he’s back to you within the hour.  He also sells Belles, I believe, so he can advise you as to whether they would work well together.