I know Jupiter Lee of Jupiter Audio Research and followed his extensive modifications to the stock Sennheiser HD650. After multiple preliminary iterations, his completed modification, the JAR650, arrived in mid-2018, along with a stock HD650 for comparison purposes. After intensive comparisons of the JAR650 with the HD650, I posted a review (linked below) praising the JAR650 for improving virtually everything that is good about the stock HD650 (a headphone whose sonics I admire): https://www.head-fi.org/showcase/jupiter-audio-research-j-mod-hd650-mod.23188/reviews Subsequently, Jupiter revised the mods somewhat based on user feedback, and I received the final-form JAR650 in early 2019. The final-form JAR650 took those improvements a bit further and IMO represents a sonically significant upgrade of the stock HP. I'm not aware of any revisions to the JAR650 since that time. I have multiple headphones and thus use any one headphone infrequenty; I put no more than 25-30 hours on this JAR650. Regarding cables, in my review of the JAR650 I used a stock Sennheiser HD650 cable, which I no longer have. I replaced it with a good 10 foot Periapt balanced cable. I have ~$550 total in this JAR650. My sell price is $375: this includes the JAR650 + cable, as well Paypal fees and shipping w/in CONUS only. Please, no trades or lowballs.