While most of this forum is dedicated to top of the line, highest of high end, light-at-the-end-of-the-tunnel end game, etc, I think Zach's take on a budget friendly pair of T50 mods--the ZMF Classics--deserve some serious attention. I have been using them as my office headphones for months, and paired with the SDAC+MCTH, I daresay this may be one of the best bang-for-buck mid-range combos in the hobby right now. The Classics are $300 for single-ended, $400 for the balanced versions. A while ago, I did some side-by-side comparisons between them and the HD600 and the results were heavily in favor of the Classics (I used the HD600 because I think they're much more similar to the Classics; the smooth, warm character of the HD650 is still unique). Now, I'm a HUGE fan of the HD6x0, and I think that they are easily some of the most coherent, natural, detailed, and enjoyable headphones at their price point.... that said, the Classics crush them in most respects. In short, the Classics are more coherent, more revealing, and more forgiving than the HD600. Oh, and did I mention that the bass makes the HD6x0 sound like Sennheiser just plain forgot about double digit frequencies altogether? In my mind, that makes these headphones a little bit of a Big Fucking Deal, posing a serious threat to usurping the mid-budget ($200-500) throne on which the Sennheisers have sat for as long as I've been in this hobby. (NOTE: I was using the MCTH and Vali 2 for these impressions... I KNOW the HD600 can do better, but felt that it would be most fair to compare the two out of amps that can drive both. At the end of the day, though, I don't think there's an OTL amp in the world that can make the HD600 catch up to the Classics.) I think the best description of their sound signature is to compare them to a good pair of sunglasses: you can see everything perfectly clearly through them, but they take the bright edge off of modern recordings. They are not intended to be flat, but are close enough to it that no frequencies are distracting from any others. A tablespoon of extra bass, Zach's usual midrange magic, and easy treble makes for an awesome listening experience. Coherence: I usually use this term to describe the transition between bass, mids, and treble, and all three are very well integrated. In this case, however, I'm also describing how sounds bleed together when tracks get busy. I listen to a lot of metal, where there's a lot of activity and noise going on at once. I have never thought of the HD600 as lacking coherence... until I did side-by-side comparisons with the Classics. They have a real tendency to be wooly, hazy, or worse when things get busy, whereas the Classics are always tight--and yield better detail as a result--so much that it makes it hard not to give them preference over the Senns. Bass: Holy fuck, bass. There is no competition at all here going back and forth between the Classics and the Sennheisers. Seriously. The Classics do NOT have ruler flat bass that extends clean out to 1 Hz like some planars (OG HE-400, pre-fazor LCD2), it's a little boosted over neutral with some rolloff in the sub-bass. That said, they slam, rumble, and roar in a way that the HD600 could never dream of and are extremely satisfying. For rock and metal, it's perfect for enjoying how the bass plays in with the rest of the music and supports the other instruments, but not loud enough to be distracting. These are not basshead cans. Mids: Beautiful, slightly warm, relaxed. In terms of tonality, if the HD600 are dead-on realistic (they're not, but just for the sake of discussion), then these are just a step or two in the relaxed direction from that. Note that "warm" and "relaxed" are not the same thing, and this is not a step in the direction of the warm, smooth character of the HD650. Hence my description of their sound signature as being like a good pair of sunglasses: they're clear, natural, and detailed, but just easier for modern recordings. Treble: My description of the treble is similar to the midrange, just slightly relaxed from realistic while still maintaining excellent detail, coherence, and extension for the price point. The treble is more relaxed than the mids, however, I am very hesitant to call these headphones dark at all. Put on a pair of dark headphones (e.g. OG LCD2) and switch to the Classics, the Classics will sound neutralish and treble-forward in comparison. Put on the HD600 or the HD800, and the Classics will sound somewhat dark. The treble, like the mids and bass, strikes an excellent balance between clarity and ease of listening. "But ohshitgorillas," you say, "you sound like a shill when you say nothing but positives. Surely there must be negatives?" Sure: * Extension suffers slightly compared to the HD600, and soundstage width as well. The difference, however, is embarrassingly small considering that the HD600 are open-backed and the Classics are closed. Given that they have deeper cups, and are angled, the Classics present a slightly more forward soundstage... however, soundstaging is not exactly the strength of either can. * They are heavier than the HD600. After all, the Senns are almost 100% plastic, and the Classics are planars. I have no issues wearing the HD600 and find them more comfortable, however, those with big heads and/or big ears will appreciate the depth and size of the Classics pads. * Comparing things to the Atticus or HD800, I can find several areas of deficiencies (he said to the surprise of no one). While macrodetail is all there, the lack of microdetail is apparent. Also, the TOTL cans have vastly superior separation/imaging, making the Classics sound like everything is kinda mashed together. That's not to say that instrument separation is BAD on the Classics, just that it's superb on the HD800 and Atticus. * Zach hand makes (mods) all of these by hand... that's a benefit, not a negative, UNTIL the masses realize that these are superior to the Senns and start ordering them en masse, and Zach ends up with a backlog 800 headphones deep. (A friend of mine said of the Atticus after hearing them, "I really wish I could afford to get myself a pair while he's still making them by hand... that's only going to last so long...") I'm going to cut myself off here and come back to this a little later on for further thoughts. I'll also link to my previous head-fi review and detailed comparisons to the HD600 (https://www.head-fi.org/threads/zmf-classic-mk3-discussion-and-impressions.834827/page-3 in this thread.... I can't figure out how to link to a specific HF post, and I'm not about to spend 5 minutes of my life figuring it out). Seriously y'all... these cans are giant killers to my ears, and there has been very very little discussion around them. I love my pair and am over the moon with the value, especially when paired with the MCTH and the ZMF Atmos C cable (gorgeous!). Anyone in the area is welcome to stop by my place in central CT and hear them for yourself.... I might be convinced to send them on a short loaner tour, provided someone is willing to send me something to fill the void while they're gone. Cheers!