ZMF Atrium - new open-back co-flagship

[heliosphann]

As someone who has been fortunate to own both the Glenn and the Airmid, I feel obligated to respond here. In actuality there is no "velvet rope secret club" and if there is, I'm not in it.

I used to own the La Figaro 339 and spent hours reading that thread, learning about various tube rolling combos. One member in particular, @UntilThen seemed to know a lot about tubes that sounded great in the 339, so I reached out to him via DM. In one of our conversations he mentioned he was buying a Glenn OTL, and suggested I check out the Glenn thread, so I did. A few months later I sent Glenn a deposit for my own GOTL and 3 months later, I was a Glenn owner. No secret handshake required.

I spent quite a bit of time in that thread, and the other GOTL owners, who are a bunch of passionate and helpful members, helped me learn the ins and outs of owning this amazing amp and draining my wallet by suggesting various tube types and rolls for the Glenn.

One of those members whom I spent time interacting with, @L0rdGwyn , announced he was selling his GOTL and building his own amp. Of course I was curious to hear what LG had come up with, so several months later he sent me his prototype, called the Airmid, to listen to and possibly review. Well, needless to say I was impressed enough with the Airmid that I posted in the Glenn thread that I was putting my GOTL up for sale. @robo24 responded literally within less than 5 minutes of me posting, and now he is enjoying my GOTL. Lucky perhaps, but again no secret handshake required.

LG's plan originally was to build and sell the Airmid, and in my Airmid review I did say to "run, not walk" and order your own Airmid. Unfortunately for several reasons, the Airmid was only available for sale for a few weeks, hence why there are only six in existence AFAIK, and have become unobtanium.

I mention all of this because I currently have another entirely different amp in my home that was designed and built by LG that I will be reviewing soon. This amp, called the Aegis, shares many of the same sonic qualities of the Airmid. Not only that, unlike the Airmid, it sounds great with planars too.

If you want admission to " the secret club" one only needs to read and interact with other members. A subscribe to my Youtube channel (link in signature) will help as well.

What he said

 

[L0rdGwyn]

Yes as was said I do not have time to run a side business building amplifiers, it's just too time consuming to operate in addition to a full time job. Some custom amp builders are making it work, but I gave it a try and it isn't for me. I think it's already been discussed on this thread, but Aegis is an experiment to release a DIY project. It's a way to give people access to something I've designed. I know DIY isn't for everyone, but I've paid special attention to making this amplifier easy to build and I will provide very detailed instructions on where to source the parts, test, and build. It's also a unique design amongst headphone amps, nothing like it on the market, so I'm hopeful that it will be a success.

 

[UntilThen]

This might be simplifying things but I see 3 tiers of power tubes common in most tube amps.

1. Amps that uses 6as7g/6080. Expensive tubes are GEC 6as7g, Tung Sol 5998, Bendix 6080

2. Amps that uses KT88, EL34, 6550, 6L6GC, etc. If you think that NOS tubes in 1 are expensive, wait till you hunt around for NOS tubes at this level.

3. Amps that uses 300b tubes. Now you're talking big turkey dollars if you are buying good 300b tubes.

 

[Monsterzero]

1. Amps that uses 6as7g/6080. Expensive tubes are GEC 6as7g, Tung Sol 5998, Bendix 6080

You forgot the Chatham 2399, which is a rebranded Tung Sol 5998 as well as the Western Electric 421a, which is not a 5998 rebrand, contrary to popular belief.

3. Amps that uses 300b tubes. Now you're talking big turkey dollars if you are buying good 300b tubes.

Yeah, I've had this conversation a few times recently with other members. God tier 300b tubes are insanely priced and for that reason alone I'd never own a 300b amp or DAC, but god bless you if you can afford them.

 

[Skyediver]

As someone who has been fortunate to own both the Glenn and the Airmid, I feel obligated to respond here. In actuality there is no "velvet rope secret club" and if there is, I'm not in it.

I used to own the La Figaro 339 and spent hours reading that thread, learning about various tube rolling combos. One member in particular, @UntilThen seemed to know a lot about tubes that sounded great in the 339, so I reached out to him via DM. In one of our conversations he mentioned he was buying a Glenn OTL, and suggested I check out the Glenn thread, so I did. A few months later I sent Glenn a deposit for my own GOTL and 3 months later, I was a Glenn owner. No secret handshake required.

I spent quite a bit of time in that thread, and the other GOTL owners, who are a bunch of passionate and helpful members, helped me learn the ins and outs of owning this amazing amp and draining my wallet by suggesting various tube types and rolls for the Glenn.

One of those members whom I spent time interacting with, @L0rdGwyn , announced he was selling his GOTL and building his own amp. Of course I was curious to hear what LG had come up with, so several months later he sent me his prototype, called the Airmid, to listen to and possibly review. Well, needless to say I was impressed enough with the Airmid that I posted in the Glenn thread that I was putting my GOTL up for sale. @robo24 responded literally within less than 5 minutes of me posting, and now he is enjoying my GOTL. Lucky perhaps, but again no secret handshake required.

LG's plan originally was to build and sell the Airmid, and in my Airmid review I did say to "run, not walk" and order your own Airmid. Unfortunately for several reasons, the Airmid was only available for sale for a few weeks, hence why there are only six in existence AFAIK, and have become unobtanium.

I mention all of this because I currently have another entirely different amp in my home that was designed and built by LG that I will be reviewing soon. This amp, called the Aegis, shares many of the same sonic qualities of the Airmid. Not only that, unlike the Airmid, it sounds great with planars too.

If you want admission to " the secret club" one only needs to read and interact with other members. A subscribe to my Youtube channel (link in signature) will help as well.

I apologize if my joke brought offense. As a former owner of a Glenn OTL, I agree 100% with all of the warmth, welcoming nature, and friendliness of the folks in those threads, etc.

Still doesn’t make it enjoyable if it’s so FREAKING HARD to obtain any of these great amps, even if there’s legitimate reasons for that. Small, one man operations being the primary reason, at least from my experience.

I didn’t creat the nickname “unobtainium” which sticks to these OTL models, after all.

 

[Monsterzero]

Still doesn’t make it enjoyable if it’s so FREAKING HARD to obtain any of these great amps, even if there’s legitimate reasons for that. Small, one man operations being the primary reason, at least from my experience.

I totally get that, but it's these one man amp builders that are passionate about this hobby themselves, just like the rest of us. Unlike something you can stop by Amazon and buy in a click of a button and have it arrive on your doorstep in two days, these independant amp builders aren't cutting corners by using cheap internals and actually care more about how their amps sound than they do about profit margin.

Sure, typically there is a wait to have an amp built, the ordering process is often unconventional and more often than not, a leap of faith is required, as hearing prior to buying is extremely difficult. I get all of that, but in the end you end up getting an amp that blows most commercialy available amps in the same price range( or higher) out of the water. It's not too dissimilar to buying a ZMF headphone, built by a hobbyist, for hobbyists, with extra care and pride taken in the workmanship and sound, and it might take awhile for you to get it, but the end result is totally worth it IMO, and I'm not an exceptionally patient individual.

 

[geoffalter11]

Where do I begin? I'm usually quiet going about my own business but sometimes my name gets mention, like now for instance by @Monsterzero I am no expert though and I'm not technical. I live by experience by trying out the amps for myself.

First of all, I have enjoyed my time with 3 ZMF headphones - Atticus, Eikon and Verite Open and God knows why I sold them. I went through more headphones and amps than my daily meals. There's always the intention to get another ZMF headphone again in the future but there's always that one more tube amp to get. It's like I don't have enough !

More of the ZMF dynamic headphones are ideally suited with OTL amps and also transformer coupled amps that I have owned in the past and also presently. The amps are:-

La Figaro 339i (OTL amp) - this is a diamond in the rough. Amazing bass weight and wide soundstage. Get a pair of Tung Sol 5998 or Bendix 6080wb and you'll be smiling. Other tubes that are more affordable are the Mullard 6080, Svetlana 6H13. The holy grail is of course the GEC 6AS7G.

Felix Audio Elise and Euforia - OTL amp as well. These have lovely traditional tube amp tone that should pair very well with ZMF headphones. They share the same La Figaro's power tubes mentioned above.

Glenn OTL amp - I owned this for about 2 years. This is the Super 9 OTL amp that I call it because there are 6 sockets for power tubes (6BX7), 2 for c3g drivers or one 6SN7 driver. Love this amp and should have kept it but in the name of the game, I have to move on.

ALO Audio Studio Six - this is a very nice transformer coupled amp for ZMF headphones but it's a bit pricey but 2nd hands once are more affordable. It's very well made and have 4 headphones output. You can literally plug in 4 ZMF headphones and it won't run out of steam.

Woo Audio WA22 - another transformer coupled amp that shares the same compliments of power tubes as La Figaro 339. This is another superb amp for ZMF headphones. How do I know? Because I've used it with my 3 previous ZMF headphones before.

Ultrasonic Studio Oblivion - this I have currently and will drive any headphones including Susvara. Clarity, details, wide soundstage and fast transients are it's traits. This one's a keeper for me.

Ultrasonic Studio Odyssey - transformer coupled amp that uses KT88, EL34, 6550, 6L6GC, etc as power tubes. This one uses very good boutique parts such as Sowter transformers, Yamamoto sockets, Mundorf caps, etc. This is my priced baby.

I had known @L0rdGwyn since the days of Glenn OTL amps and I am pleased to see he is now a very competent amp builder but he doesn't have time to do it on the side line. On his thread, you can see a wide array of amps that he has build. They are amazing looking but I never had the pleasure of listening to one. There are some who have own it and praise them highly. Zach himself has a couple of Keenan's amps.

Other boutique amp builder are the 1010 amp thread. Hope I got that name right. Lovely amps there too. @leftside is probably the best person to contribute on this as he has 2 amps build by that amp builder.

Other tube amps that I never had the pleasure to try are DNA Stratus, Stellaris and Eddie Current Studio 300b amps. They should be lovely. I would have love to try these but hey there are only so many tube amps I can get my hands on and I am about to retire from more amps after the arrival of Telemachus (300b amp) next April 2023.

Last but not least there are the range of Cayin amps and Ampandsound amps. Too many for you to choose from. You can't complain there aren't enough to choose from.

However getting the amps is just the beginning. Then follows the hunt for lovely NOS tubes. Aren't you glad you fall into this rabbit hole? Enjoy because there is no life without tube amps.

P/S - there's also Auris Nirvana and it's siblings. I've audition Nirvana twice and then had Odyssey custom made. At this level, the amps are pricey but gorgeous in looks and sound.

These are great posts, and as @Monsterzero stated, all one must do is be curious and you will ultimately land where you want to land in this hobby. These are all fantastic tube amps being written about. I have had the pleasure to speak a bit with @L0rdGwyn and he is a gentleman of the highest order. Over the yrs I have mostly had odysseys with SS amps, not willing to have tubes around my young children. As they have gotten older, I have delved into the world of tubes.

One more amp to add into this list of amazing tube amps with ZMF headphones is the Icon Audio HP8 MK2 Signature. It is sonically perfect with the Auteur, Atrium, and every other ZMF I have tried. It is such a beautiful, musical and all around incredible amp. It is not a 300B amp. It has 3 tubes and the most beautiful copper plate. A 12AX7/12AT7 driver and 2 6SN7 power tubes. I have spent a lot of time talking with other head-fi members and learning in the threads how to pair different tubes to best maximize the HP8. Bottom line, it is a sensational amp. I am currently enjoying the perfect symbiotic relationship of image specificity, tone, gentility and voracity as I write this.

As are all the Glenn, Airmid's and every other tube amp named above. I have come to the conclusion that the best headphone experience for me involves a tube amp. I am already hunting for my next.

Perhaps a Trafomatic Head 2, Stratus V4, or whatever I can afford when the day arrives.

There are many roads to sonic bliss, and it has taken me a long time to realize that my road to sonic bliss leads through a high quality tube amp. I still love my Cembalo Labs Spring 1. A unicorn amp with secret powers, but more and more I find myself longing for the sound of the HP8 with my Auteur or the Atrium I still have here on loan. I can't get enough. It also happens to sound sensational with my Radiante 1706 and my LCD-4z. There isn't a headphone I have tried that doesn't love the HP8.

Atrium and HP8 are currently giving me spine inducing shivers.

 

[UntilThen]

Yeah, I've had this conversation a few times recently with other members. God tier 300b tubes are insanely priced and for that reason alone I'd never own a 300b amp or DAC, but god bless you if you can afford them.

I have own Destiny a 300b amp and am about to get another Telemachus 300b amp. Much as there has been a craze with 300b amps lately, I do not imo think it's the best type of tube amp. It is unique in tone, being more mid centric with a lovely mid bass, lower bass presence. You certainly should have one in your collection if you're nuts about tube amps but never disregard the others. As usual ymmv.

Amps that uses the famed EL34 and KT88 are more linear, tighter in tone with a more focus impact.

When you get to review Aegis, you will be able to suss out the differences of the transformer coupled amp against the Airmid which is OTL.

It really depends on your preference. Some tube amps are warm and very tubey sounding. Others lean slightly neutral with fast transients and cutting edge tone. Is one better than the other type? Not really. Really depends on how it fits with your system chain and preference.

 

[Skyediver]

I totally get that, but it's these one man amp builders that are passionate about this hobby themselves, just like the rest of us. Unlike something you can stop by Amazon and buy in a click of a button and have it arrive on your doorstep in two days, these independant amp builders aren't cutting corners by using cheap internals and actually care more about how their amps sound than they do about profit margin.

Sure, typically there is a wait to have an amp built, the ordering process is often unconventional and more often than not, a leap of faith is required, as hearing prior to buying is extremely difficult. I get all of that, but in the end you end up getting an amp that blows most commercialy available amps in the same price range( or higher) out of the water. It's not too dissimilar to buying a ZMF headphone, built by a hobbyist, for hobbyists, with extra care and pride taken in the workmanship and sound, and it might take awhile for you to get it, but the end result is totally worth it IMO, and I'm not an exceptionally patient individual.

I think we're saying the same thing? My main point is even if we all love the passionate nature of how these amps and headphones come into being and what makes them different than a mass-produced unit, I don't care how much love and attention someone has put into it if I can't, as an end-user consumer, BUY IT in a reasonable timeline and fashion!

Maybe it's me, but I'd assume I'm not alone in this position as an end-user of this fabulous gear? I get that there's a push-pull natural tension between the headphone and amp builders who are high on the passion side of the equation. It's just hard and more than a bit frustrating to read/hear about FANTASTIC creations in these very same forums... but you can't buy them easily, even if you do have the funds for purchase. Or gotta wait upwards of a year (think abut that, a YEAR!) to get in line for an order. Again, I emphasize understanding ALL of the reasons that this is the nature of our small, extremely passionate, but very niche community and the consumer market that supports it.

Doesn't mean that it still kinda sucks at the end of the day when you want to buy and ENJOY said products in your home, as someone who's read about all these "tubey aural delights" these products provide, including the justly named unobtainium ones.

Honestly, I wasn't trying to create any drama with this position, which may indeed just be my own. Mainly wanted to get to the core of a few TOTL OTL amps that DON'T have any of the challenges we're talking about, that was my. main point. Which several have graciously responded to, including yourself, so truly, a thank you for that!

 

[goldwerger]

Much as there has been a craze with 300b amps lately, I do not imo think it's the best type of tube amp. It is unique in tone, being more mid centric with a lovely mid bass, lower bass presence.

Amps that uses the famed EL34 and KT88 are more linear, tighter in tone with a more focus impact.

First, thank you both @UntilThen and @Monsterzero for sharing your insights. As a tube newb, I keep learning and found these summaries helpful.

From my limited experience, I share the above specific observations. One of the more profound experiences I've had with a ZMF headphones was testing my VC with the 300B based Red October. That extra bass texture was quite magical, as well as a sense of expanded soundstage.

I currently use an EL34 based Auris Nirvana, which I always discribe, first and foremast, as "linear" (as an aside, it is also a rather powerful TC amp that is very versatile).

Question, if I may -- since demo-ing the Airmid at ZMF's at CanJam Chicago, I have a remaining yearning to that sound signature. Realizing that one is off the table (and not looking to build one myself), is there any amp you know that may have a similar sound signature?

 

[g0ldl10n]

Do what you want with your money but I do not think those will sound good on the atrium. The t50 is a closed back, and as such the only oval pads I see available on the site are solid leather. ZMF open backs work best with perforated leather as they're already pretty bassy. Having tried some ZMF solid pads on their open headphones out of curiosity I think the oval pads will dramatically increase bass to beyond enjoyable levels.

Hmm, this comment has really inspired me to do some slight modifications/tinkering on my end, and wow, it is quite insane how much those perforated holes effect the sound that you receive. I covered up all the perforated holes on the stock leather pads, and wow, crazy difference! For my preference, there is probably a happy medium between the amount of perforated holes in these stock pads - for instance, I think these might sound near perfect for me, if they reduced the amount of holes by about 50%. I know there are Hybrid pads which are supposed to capture a nice medium between the lambskin and suede pads, but from what I have just experienced, there is likely a way to get to a similar place by just reducing the amount of holes in these pads.

Anyone can try this - cover up all of the perforated holes on the outside rim of stock leather Atrium pads with some simple not strong tape, as to not damage them, then give them a try.

 

[UntilThen]

Or gotta wait upwards of a year (think abut that, a YEAR!) to get in line for an order.

Good things comes to those who wait. The steady stream of DNA Stratus and Stellaris owners will tell you so. That's just one example. I'm waiting 8 months for my Ultrasonic Studio Telemachus. Some are willing to wait while others will not.

Sure you can buy immediately from Cayin, Ampandsound, Woo Audio, Feliks Audio etc if that's your preference. I won't comment of whether boutique custom build amps sound better than commercially produced ones because I've never had the chance to compare them apart from Nirvana vs Odyssey and that's not side by side comparison.

 

[UntilThen]

From my limited experience, I share the above specific observations. One of the more profound experiences I've had with a ZMF headphones was testing my VC with the 300B based Red October. That extra bass texture was quite magical, as well as a sense of expanded soundstage.

I currently use an EL34 based Auris Nirvana, which I always discribe, first and foremast, as "linear" (as an aside, it is also a rather powerful TC amp that is very versatile).

Question, if I may -- since demo-ing the Airmid at ZMF's at CanJam Chicago, I have a remaining yearning to that sound signature. Realizing that one is off the table (and not looking to build one myself), is there any amp you know that may have a similar sound signature?

When the bass drops from a 300b amp, your internal organs will be dancing.

As I have not heard the Airmid, perhaps you can describe the sound characteristics. How does that compare with your Auris Nirvana, which I think is a very good sounding tube amp.

If Monsterzero prefers the Airmid to the Glenn OTL, then the Airmid must be rather special because I thought the Glenn OTL is great.

If Airmid is so well received, perhaps @L0rdGwyn can reconsider making it available as a business ! However he seem to think Aegis is more resolving. Personally I prefer point to point wiring and not PCBs.

I do not generally promote the amps that I have but let me just state that Oblivion and Odyssey satisfy me completely. I could have just stop here and be happy.

 

[Marutks]

These are great posts, and as @Monsterzero stated, all one must do is be curious and you will ultimately land where you want to land in this hobby. @L0rdGwyn

Monsterzero is very lucky to have "dead quiet" OTL amp - Airmid. Most tube amps are not quiet.
The Blue Halo is dead quiet only if you use 6N6P tubes ( they need adapters ).

 

[goldwerger]

When the bass drops from a 300b amp, your internal organs will be dancing.

As I have not heard the Airmid, perhaps you can describe the sound characteristics. How does that compare with your Auris Nirvana, which I think is a very good sounding tube amp.

If Monsterzero prefers the Airmid to the Glenn OTL, then the Airmid must be rather special because I thought the Glenn OTL is great.

If Airmid is so well received, perhaps @L0rdGwyn can reconsider making it available as a business ! However he seem to think Aegis is more resolving. Personally I prefer point to point wiring and not PCBs.

I do not generally promote the amps that I have but let me just state that Oblivion and Odyssey satisfy me completely. I could have just stop here and be happy.

Thanks!

I tried, like many, and asked Keenan if he'd build more of those Aidmids, but his mind is set to move forward due to the complexity of this one (I'm really sad, but of course respect his personal reasons)

The Airmid has that beautiful OTL harmonics, but without any notable coloring, and beyond that has very holographic feeling soundstaging, almost like a sense of reverberation off an imaginary wide hall.

I'll definitely keep the Oblivion and Odyssey in mind. Given you tried the Nirvana as well, I assume you liked those better, so I'm intrigued