[George Hincapie]

Without an output transformer, an OTL's output impedance will be relatively high. I suppose it depends on your tubes (and I'm not an expert in OTL design or tube selection), but the ideal OI for an Arya SE should be less than 4Ω (16Ω if you're going for 2:1), and most OTL's I know are triple or more of that. The OTL will still drive your headphone, but if its OI is too high, you will have very little electrical dampening, which will definitely have audible effects. Whether you like that effect or not is your preference, but it isn't everyone's cup of tea.

I did try running my Arya Stealth through my BHC (120Ω vs 32Ω) and it's definitely okay for casual listening, although I feel it loses some much texture and microdynamics from lack of dampening. I don't think it'd be my favorite critical listening amp. Similarly, the Caldera is a bit better match at 60Ω, but I don't think it'll get much dampening either.

There's an article by NwAvGuy that goes into great depth about headphones and output impedance if you Google for that, so that may be of some interest.

Really interesting, thank you.

Impedence is something I've never understood, and it's been so long that I feel stupid asking someone to explain.

My amp apparently uses impedence converters. I attach an image of the spec sheet for your interest.

 

[joshua1122]

My amp apparently uses impedence converters.

That's a neat concept idea. How do you like that amp?

 

[gonintendo]

If you wouldn’t mind trying some with either pad and sharing your thoughts that’d be cool

I gave the track "Keep Ya Head Up" by Tupac a listen, here are my thoughts on the following pads:
Stock lamb:
Bass sounds nice and full, but not overpowering. The drums are snappy and a bit compressed sounding, but they sound like they're recorded that way not that the headphone is missing dynamic range. Everything is relatively balanced in the mixed but percussion is a bit forward.

Thin lamb:
Bass is tightened up a bit, sounds punchy and fast. I quite like it but it is maybe a tiny bit lean for this track if you like more bass. The attack is a bit more accentuated over the body of the note. Drums are brought slightly forward, but the cymbals and snare sound more in balance to me than the stock pad where the cymbals are a bit more dominant (this is a subtle difference)

Cowhide:
Tonally similar to the thin lamb but the drums and bass are even more punchy. Might be a bit too much here.

Thick lamb:
The drums take a step back on these, sounding more in line with the vocals, while the bass takes a step forward. Bass sounds fuller, and while you can hear the attack, the body has the focus over the attack.

Vocals sounded mostly the same across all 4 pads. Staging differences were pretty much as I described in my other post.

My preference for this track is 1. Thin lamb 2. Stock lamb 3. Thick lamb 4. Cowhide
Thick lamb sounded the most like how I expect this song was meant to sound on gear "of the time," while the thin and stock pads were a more neutral sound (the tradeoff being a bit more attack and clarity with the thin pads, vs a more full sound with the stock pad). The cowhide pads pushed the punch-factor a bit over the edge here for me, to the point where I wanted to turn the volume down a bit. They were still an enjoyable listen but I think the vibe was better with the other pads.

 

[Raidersfan8118]

I gave the track "Keep Ya Head Up" by Tupac a listen, here are my thoughts on the following pads:
Stock lamb:
Bass sounds nice and full, but not overpowering. The drums are snappy and a bit compresses sounding, but they sound like they're recorded that way not that the headphone is missing dynamic range. Everything is relatively balanced in the mixed but percussion is a bit forward.

Thin lamb:
Bass is tightened up a bit, sounds punchy and fast. I quite like it but it is maybe a tiny bit lean for this track if you like more bass. The attack is a bit more accentuated over the body of the note. Drums are brought slightly forward, but the cymbals and snare sound more in balance to me than the stock pad where the cymbals are a bit more dominant (this is a subtle difference)

Cowhide:
Tonally similar to the thin lamb but the drums and bass are even more punchy. Might be a bit too much here.

Thick lamb:
The drums take a step back on these, sounding more in line with the vocals, while the bass takes a step forward. Bass sounds fuller, and while you can hear the attack, the body has the focus over the attack.

Vocals sounded mostly the same across all 4 pads. Staging differences were pretty much as I described in my other post.

My preference for this track is 1. Thin lamb 2. Stock lamb 3. Thick lamb 4. Cowhide
Thick lamb sounded the most like how I expect this song was meant to sound on gear "of the time," while the thin and stock pads were a more neutral sound (the tradeoff being a bit more attack and clarity with the thin pads, vs a more full sound with the stock pad). The cowhide pads pushed the punch-factor a bit over the edge here for me, to the point where I wanted to turn the volume down a bit. They were still an enjoyable listen but I think the vibe was better with the other pads.

I appreciate that write up. Looks like stock is probably good for me then. I’m possibly interested in a thin pad though.

 

[yolosauce]

If you've been listening to the Atriums for several months your brain will need to adjust to the bass of the Caldera. Certain songs will sound light on bass only because the Atrium added so much of it. I used dirac to make my speakers flat from 20hz to 300hz and they are very similar to the Caldera. Extremely accurate and slams hard when the song was recorded that way.

 

[wkesquire]

They arrived! Glamour shots with better lighting tomorrow, but posting an initial pic to show that they arrived and look gorgeous. I thought I’d post before giving them a listen, but I couldn’t help myself. A few rapid reactions:

First, right off the bat—easily the most resolving ZMF I’ve heard yet, bass extension is just as fantastic as everyone else who’s heard them has reported. I spent a lot of time listening to my reference tracks closely on my Atrium and VC, and I was convinced that there wasn’t much more to hear. To be fair, there isn’t a ton more to hear in the music, but there certainly is more and the Caldera reveals those details ably, at least with the stock pads. I’m not even going to pretend to give an appropriate sound impression at this early point beyond saying I’m pleased with how these headphones sound right out of the box off my Yggy LIM + Oor/Hypsos stack. My WA5-LE is at the office. To be continued…

Second, someone posted earlier that these were the most open ZMFs. Having heard all of the open-backed ZMF models, I think that’s certainly true. I could get away with listening to my Atrium with my wife and daughters talking in the background. Not so with Caldera, unless I crank it up, which I’d prefer not to do.

Third, I’ve not had them on my head for very long, but they are noticeably heavier than my Koa Atrium, which feels like the lightest full-sized headphone I own, but the crescent headband and the level of clamp force make these still feel super comfortable. Happy with my decision not to worry too much about weight.

Fourth, as for aesthetics, this picture doesn’t do it justice, but they are beautiful. Far from clashing with the silver grilles and rods, the charcoal chassis actually ties the color scheme together, in my opinion. The charcoal reflects some of the warm chocolatey tones from the wood. Also, I noticed this in the videos (more so certainly than the pics on the website), but the fabric behind the silver grille nicely matches the color of the wood. A subtle touch indeed, but again it serves to tie everything together. The kingwood/charcoal/silver combination is a very coherent design. Cheers to Zach, Bevin, and the whole team for nailing this one from a design perspective.

Again, glamour shots tomorrow.

 

[gonintendo]

They arrived! Glamour shots with better lighting tomorrow, but posting an initial pic to show that they arrived and look gorgeous. I thought I’d post before giving them a listen, but I couldn’t help myself. A few rapid reactions:

gorgeous set!

 

[gonintendo]

I just weighed mine and they come in at 534g with the cowhide pads on (coffee gold with mag chassis) if anyone is curious

 

[LoryWiv]

Surely that depends on the OTL? Mine is driving Arya SE beautifully, so I'd hope Caldera would fall into the same camp.

Which OTL do you run?

 

[Raidersfan8118]

If you've been listening to the Atriums for several months your brain will need to adjust to the bass of the Caldera. Certain songs will sound light on bass only because the Atrium added so much of it. I used dirac to make my speakers flat from 20hz to 300hz and they are very similar to the Caldera. Extremely accurate and slams hard when the song was recorded that way.

I think you’re right. I tried some songs earlier and I was like hmm these actually aren’t bad for hip hop bass wise. They really slam quite nicely. I feel like these are a better all around headphone than I was expecting. I was kind of just expecting rock and metal to shine but it really does everything awesome that I’ve listened to.

 

[klardotsh]

I kind of had a suspicion that you have the RU6. Guess it’s time to get a 4.4 mm adaptor just for some fun

Also… my caldera came in a day early than expected! Shoutouts to the team at zmf and fedex for the swift shipping. They look divine. As good as I expected based on the launch YT videos. Excuse me I’ll leave this snap here and go listen……

All these in-the-wild-not-in-the-lab pictures of the Coffee Oak + Gold cans are making me second guess my Kingwood decision, wowza those are beautiful! (And I know my Kingwood will be too, when it ships, they're both properly art)

 

[George Hincapie]

Which OTL do you run?

LTA MZ3

 

[George Hincapie]

That's a neat concept idea. How do you like that amp?

I love it. It's my first tube amp, so I have no frame of reference, but I'm eagerly awaiting my new ZMF VC to try with it.

 

[NutritiousNoodles]

I was putting my whole library in shuffle. Couldn’t find a track that don’t sound good.

 

[SpeleoFool]

Woke up this morning very concerned about another caldera where I live. Good timing Zach? https://www.cnn.com/2022/11/28/weather/hawaii-mauna-loa-volcano-eruption/index.html