looking for a dac

Starting Point systems NOS dac TDA 1543.... With these cheap price dac I forget all future possible upgrade at any price...Rightly implemented this battery dac that I drive with an external lithium battery has no defect at all in my system and to my ears … The risk is low you can buy one used for around 100 bucks...My system is Sansui AU-7700 amplifier with Mission cyrus 781 speakers,akg K 701 headphone, a very good system, entirely cleaned of vibrations and resonance that sound so great that I smile  without any idea of upgrading it...Impossible to really upgrade that under 20,000 bucks...I say that to give to you a context for my advice with a dac...The dac is in my experience the most difficult piece to buy if we want a good ratio quality/price...I am lucky...

thanks for the responses
all the info i can gather is most helpful

the NAD at $1k is better than the built in Bluesound DAC, I believe it is the M-51
Brother in law has both
IMO the Amber II by Lampizator is much more musical but slightly less etched/detailed. New about $2,200
Can every now and then be found used...
maybe save up for something significantly better than the competent DAC in the Bluesound...
have fun
enjoy the music.

Do try to get the Bluesound on a seperate circuit, all your digital stuff, wallwarts, etc away from the analog circuits....