I'm the original owner of this Havana DAC modified by the Parts Connexion. This unit is in mint condition and functions perfectly. I discussed upgrades with Chris Johnson of the Parts Connexion (former head of Sonic Frontiers). He recommended the upgrades that would provide the biggest bang for my buck. Those upgrades are what were installed by his company into my DAC. The upgraded DAC greatly improves upon the stock DAC in the following areas: (1) images are more clearly defined (2) the soundstage opens up to a deeper and wider stage (3) frequency extremes are more extended and bass has greater definition and much more slam (4) dynamics and microdynamics are greatly improved. The Parts Connexion upgrades include V-cap output caps, 4 other stock caps were replaced by Nichicon caps, DH Labs silver wiring, WBT silver RCA output connectors and much more. I further improved this DAC by installing a Bendix 6385 tube that cost about $135 and upgraded the DAC chip from a Burr Brown PCM56P-L to a Burr Brown PCM56P-K chip that has tighter tolerances and is much better sonically. I also installed a HiFi tuning Supreme fuse. All the upgrades and tubes easily comes to about $500USD and that doesn't include any labor. My modified Havana maintains the analog like sound of the stock but greatly improves upon it.