Have upgraded many DAC’s and CD Players in the past and designed new DAC’s, most notably my Paradox range of without oversampling or upsampling filters, I’m of the opinion that avoiding these filters is the simplest way to get excellent sound quality.
Currently the DDDAC1794 design is my favourite and I have made and sold several of these using the DAC boards available in kit form and using my own power supply and output stage design.
More details to follow.
Chevron Audio