Greetings and many thanks to everyone who has contributed to this thread. I'm a new Head-Fi member who purchased a set of balanced Classics based on all the helpful information you've shared previously. In addition to all that's been submitted so far, I thought I'd add my experience. Not much I can say about the sound signature of the Classics that hasn't already been said better by others, but one thing worth sharing is the amp dependency these cans display. I upgraded from a Schiit Magni to a Jotunheim in preparation for the arrival of the Classics (which, incidentally, took 10 weeks to ship). After reading all the forums I was aware of their power-hungry nature and figured the Jot had plenty of juice to drive them well. I received both the amp and headphones around the same time. I gave the ZMFs about 72 hours of burn-in with pink noise before settling in for my first listening session, and I was underwhelmed. The vaunted sub-bass was there, but was coupled with bloated mid-bass that bled well into the midrange. Treble response was almost non-existent, and overall the Classics sounded dull, lifeless and lacking any definition. I tried my best to like them but couldn't get past these faults. I made the reluctant decision to sell the Classic on whenever I got around to it.
A few weeks later I ended up exchanging the Jot, and then returning that replacement, due to noise issues with the built-in phono module (story for another day
). I replaced it with a Cayin iha-6, and figured I'd give the Classics another shot before listing them on eBay. Holy Schnikes, what a difference! The mid-bass bleed was totally minimized, the sub-bass was well defined, the mids were clear and warm, imaging and clarity were markedly improved, and there was actual treble response to speak of. The Cayin amp totally transformed the listening experience, and now I totally get what everyone has been saying about the Classics.
I'm not an engineer and am also total noob, and thus have no explanation for why one high-power SS amp would so drastically outperform another. Seriously, it went from "These things are so disappointing" to "I love these friggin cans!" overnight. Power and output impedance, which from my very limited experience make a big difference in amp/headphone pairing, are similar enough to eliminate them as the reasons. Since I benefitted so much from the collective wisdom of the Head-Fi membership I figured I'd relay my experience in case others were to walk a similar path. Interested if anyone else has had similar experiences, or has some knowledge they can drop on me to explain the "why".
Thanks again, now (finally) enjoying the heck out these!