Got through the weekend with only a few hours listening on both the CO and CC (dam kids!) but wanted to share a few very impulsive early impressions.
Started with the CO on the Stratus, and man did that impress! The CO unit is clearly well used and I'm thinking fully broken in. It sounded very vibrant and fast, with bass that slams hard and decays very quickly. Very typical planar bass, but surprisingly satisfying. I tend to like slower thicker bass like the Atriums, but the CO was holding its own. It's been awhile since i've given a planar any serious play time, and resolution really shocked me. I had forgotten how resolute a good planar driver can be. There's an ethereal quality to the notes as they bloom out of nowhere, solidify, then as quickly decay back to oblivion. The longer decay of the dynamic drives gives such a different presentation.
Tone and timbre was very good, much better than I was expecting. I won't lie, I was excited and eager to try the Calderas, but also assumed they would not be my cup o tea as planars aren't normally my thing due to what I perceive as an unnatural tone/timbre. But there's the usual ZMF magic going on here, a warmth and engagement level that's very addictive. Time will tell if they become my cup o tea, but so far so good. These have a very natural presentation for a planar driver. But I need to qualify that. "For a planar". There's still that slightly metallic hardness/harshness (or steelyness, for lack of a better word) that pervades all planars i've ever listened to. The Calderas do a great job of not sounding harsh/metallic, but are not quite as natural and organic sounding as a good dynamic driver. That being said, these drivers are so good, and the headphone so well tuned, they could finally get me to add one to my full time lineup. Time will tell!
After a very late first Friday night with the CO, I had kid duties all day Saturday, finally getting back to audio after they were in bed for the night. So this time I grabbed the CC, the one I'm most interested in as I need closed back for office listening. Right away I can tell this unit needs to burn in. It doesn't sound as loose and effortless as the CO. Its stiff and a bit ham fisted with it's playback. Telltale signs of a new driver in need of burn in. So I plugged it into my spare amp and let it play overnight and all day Sunday. While that was going on I was getting what could time I could with the CO while dealing with insane kiddos who still love to have daddy play with them. Am I evil for looking forward to when they'll start ignoring me?
Fast forward Sunday night, another try with the CC. Right away giving it a good 20-ish hours burn in helped immensely. That stiffness and tightness has mellowed noticeably. Still there, but softer, more expressive and compliant. Now we're talking. First up the Stratus and my audiophile test tracks. I noticed a few things right away vs the CO. The CC is a bit darker, but with somewhat more forward mids, which I really like. Vocals sound nice and up close, where I like them. Treble is stiffer/harsher than the CO, but I think burn in will help alleviate that, time will tell. But man that bass.... tight, fast, impactful, and just plain fun. But I'll still take the AC or Bokeh for bass fun, I like more resonance and decay. Thicc is what I love! But that being said, I wasn't bored with the CC bass at all. In fact I kept searching my playlists for my bassiest music to try on the CC as I was enjoying the low end so much. The Stratus pushed the CC just fine, I was barely using the volume knob to get nice and loud, with dynamics for days. I didn't get the sense the Stratus was limited in it's ability to feed the CC all the current it needs to reach it's full potential. The thicker, warmer tube roll I run on my Stratus gave the CC a nice weight and heft to the mids and low bass.
To test whether the Stratus was up to the task of driving the CC properly, I ran my Jotunheim 2 in parallel so I could go back and forth. With the Jot the tone cooled perceptibly. Bass had a bit more initial bite, but the difference was not huge. Treble did get a bit more steely, but surprisingly not fatiguing at all. I felt the Jot had just a bit more control and power vs the Stratus, but not by much, and given the warmer, more natural tone of the Stratus, it was clear to me it was the way to go based on my preferences. I brought the Jot to work as my Woo WA3 OTL would not be a good amp for any planar driver.
So with only a few good hours of listening time my main takeaway are these are ZMF through and through. Fun and engaging, but also resolute and highly technical. I'm about to mount the protein pads after I post this, and begin a fun day of accounting with the CC at MAXIMUM ADRENALINE!