An external DAC using the AKM AK4490-series DAC chip might provide the sound you’re looking for. The Schiit Modi 3 at $99 is a bargain but bested by the new Modius at $199. 15-day money-back guarantee if not satisfied.
Another option is the use of an equalizer for the digital side. The 4-band Schiit Loki at $149 might be a good low-cost solution. Same guarantee.
If you feel in a spendy mood, the RME ADI-2 DAC ($1149) with AKM DAC chip and Bass,Treble, Loudness and 5-band equalizer controls might be the ultimate solution.
Another option is the use of an equalizer for the digital side. The 4-band Schiit Loki at $149 might be a good low-cost solution. Same guarantee.
If you feel in a spendy mood, the RME ADI-2 DAC ($1149) with AKM DAC chip and Bass,Treble, Loudness and 5-band equalizer controls might be the ultimate solution.