Thanks to @rhythmdevils for developing this mod and sending it out on tour. I have limited experience with planars, mostly with the cheaper HifiMan offerings. Most of my comparisons will be to dynamic headphones, particularly the HD650, which gets the majority of my listening time in general. Also if it helps triangulate I really like the HD58x, Focal Clear MG, and the DT177x Go, like but have some issues with the HD8xx and Focal Elegia, don't particularly like the HE400i, and hate the DT990. Unfortunately I haven't had the opportunity to spend time with the stock LCD-X so my impressions about the modded units won't reference a comparison to the stock headphone. I auditioned the modded LCD-X on several setups, including my Bottlehead S.E.X. and SW51+ fed by a Schiit Modius and the loaner Liquid Gold X amp fed by a Modi Multibit. I also did some checks with a Folkvangr and my Lyr 3 but spent much less time with those amps. My favorite pairing was with the Bottlehead S.E.X. The combination was musical with punchy bass and great vocal presence (kind of a hallmark of the Bottlehead amp). I did end up using the Roon DSP to drop the output by 12 dB to give me more adjustment room on the potentiometer, as otherwise I had a very small volume adjustment range available. The SW51+ was good as well but not quite as nice a combination, a little less lively and defined, and looser in the bass. The Liquid Gold X was excellent with these headphones, and probably the most balanced pairing overall. That makes sense given they were used in developing the mod. From the Liquid Gold X I would consider the modded LCD-X to sound balanced, smooth, and very clear. No perceived veil, tight bass, great vocals, and smooth highs. Folkvangr worked fine, but regardless of gain and impedance multiplier position didn't sound all that engaging. The Folkvangr seems to vary quite a lot by headphone and is much happier with dynamic headphones to my ears. Lyr 3 was better than Folkvangr but seemed to lack some of the balance and clarity of the Liquid Gold X and most of the emotional engagement of the Bottlehead amp. I'm not sure if this is surprising, but overall the Lyr 3 is one of my favorite amps otherwise. The sound of the modded LCD-X was, in big picture terms, similar in general presentation to the HD650, but seemingly clearer, faster, and with better quality bass. I don't necessarily perceive a "Sennheiser veil" with the HD650 in normal listening, particularly with my OTL amps, but I can see where the term comes from in comparison to this headphone. Although not specific to the rhythmdevils mod, the headphone itself is fairly heavy. No issues with the pads or earcups at all, and it was comfortable for the most part, but after a couple hours of continuous use I would start to get a hot spot on the top of my head which I could only really solve by taking a break.