In this review we take a close look at the ZMF Aegis tube headphone amplifier. It is selling for $3,499.99 USD .

Disclaimer: ZMF Headphones is not related to Headfonia in any way. The ZMF Aegis was sent to me to be featured on Headfonia.com, in exchange for our honest opinion..

ZMF Headphones

ZMF Headphones stands for Zach Mehrbach Films and they are a brand that’s no stranger to the world of high-end audio, at least within the realm of the headphone audiophile. The company is helmed by the dynamic husband-and-wife duo, Zach and Bevin Mehrbach. Together, they are purveyors of a host of fantastic-sounding and awesome-looking products. Simply drop by their website, and take a gander at their growing stable of headphones, and you won’t, or can’t, tear your eyes away from them.

When working on our designs we take our slogan very seriously; “Traditional Craft, Modern Acoustics.” We strive to make every headphone show inspiration from timeless artistry, film, culture and history. When melding this with current headphone technology and Zach Mehrbach’s proprietary damping systems, each headphone is made to become an instant classic.

That is, unless of course, you’re not particularly a fan of wood. If so, you might want to move along, as ZMF are wood masters. If you’re an audiophile, your weapons-of-choice are distinctly headphones and amps, and you’re a connoisseur of wood (is there such a thing?), then, yes, by all means, continue reading.

If you want to learn more about ZMF, you can do so on their website here. I’ve met Zach and his lovely wife on multiple occasions at different shows, and they’re always very kind and a pleasure to talk to. If you ever go to one of the sows where ZMF is present, make sure to check out their room or stand and say hello.

AEGIS

The ZMF unit we’re looking at this time is not a headphone however, but it is a transformer coupled tube amp, named Aegis.

The Aegis basically is a DIY tube amplifier, and ZMF in cooperation with Keenen/L0rdGwyn and Cayin are now building and selling a commercial version of this DIY amplifier. Here’s some history on the Aegis and how this new ZMF project came to life:

Way back in 2014, I attended a head-fi meet in Nashua, New Hampshire. Little did I know that during the t50’s days, my mind would be totally blown by a Decware Taboo tube amp. It added a spaciousness, edge, and euphony that combined for the most lifelike sound, and I couldn’t get it out of my head. After a few phone calls with Steve Deckert, and then trying tons of tube amps as the ZMF brand grew, I met Keenan at ZMFestivus years later. After Keenan started building his own amps, and with me owning a few of Keenan’s creations, he decided to make a model for the DIY crowd. That model would be the Aegis. So, Keenan McKnight is the creative mind behind the Aegis amplifier’s circuit design and its distinctive sound.

I first heard the DIY version of the Aegis Amplifier at CanJam SoCal in 2022. It was a shocking moment for me as the amount of breadth, space, oomph, and realism was overwhelming. Although it was during a show, I would “steal” the seat in the room often to listen as much as I could. And then, also having built up a huge tube collection by that time, once I got one in the shop I had to try the Aegis with all the tubes I had, and all the ZMF and non-ZMF headphones that I could find. Even after all the tube amp collecting and gear that I have gone through, the Aegis continued to make me excited to figure out what I was going to listen to every time because everything sounded exciting again.

If you like to know more about the Aegis from Keenan and Zach in video format, you can do so here:

The ZMF Aegis is a transformer-coupled amplifier, designed to effortlessly drives any planar magnetic or dynamic headphones, including the demanding Susvara or Tungsten, as well as any ZMF model. With the capability to handle high input voltages and delivering an average of 2 watts output, the Aegis ensures optimal use of the volume knob for any headphone, allowing for precise control over listening levels.

The Aegis offers six output impedance options and these varied impedance settings cater to individual preferences and the specific power requirements of your headphones. With its high wattage output and an impedance range between 5 and 85 ohms, the Aegis ensures optimal performance tailored to your and your headphones’ needs. The 4.4TRRRS jack even has a voltage divider for sensitive IEMs and headphones.

The numbers:

1/4″ Low: 5ohms : 1/4″ Med: 11ohms : 1/4″ High: 31ohms
XLR Low: 11ohms : XLR Med: 28ohms : XLR High: 85ohms

The Aegis is a “cathode follower” design and this refers to a tube amplifier configuration where the tube is used to provide current gain rather than voltage gain. The Cathode Follower design is special because it typically provides a low output impedance and high current drive capability. This design is beneficial for driving headphones with varying impedance levels effectively. It also tends to produce less distortion and a more linear response, which can contribute to improved sound quality and fidelity in audio reproduction.

The Aegis is a true tube rolling paradise amp. It is purpose built to sound amazing with stock tubes, or to let you go ham radio crazy and buy tons of tubes for your rolling delight.  Each sector; Rectifier, Output, and Input tubes have a plethora of options which we will get into later in this article.  

The Aegis price starts at $3,499.99 USD and can go up depending on the extra options you go for. It isn’t a cheap amplifier by any means, but it is a very versatile and well-built amplifier as you will see in this review. You can find the Aegis dedicated page here. You can buy the Aegis from ZMF’s shop directly here. The Aegis – according to ZMF – will be shipped within a period of 2 to 5 business days for 120V customers – while all 230/240v units will ship directly from Cayin within ten days. In Europe you can buy the 220V version of Aegis with the obligatory CE Certification for €4.099 Euro from one of ZMF’s dealers. As the Aegis originally is a DIY amplifier, it still is possible to build it yourself. That is unless you have two left hands, like me.

Tube Galore

The Aegis comes with a stock tube set which is more than ok. For me the delivered tubes were the JJ 6SL7 and EL34, in combination with a Russian Sovtek 5AR4. The beauty of the Aegis that you don’t have to be a tube collector or fervent roller for the Aegis to sound good. But at the same time this amplifier’s design does allow you to roll in an incredible amount of tubes for the input, output and rectification sector.

In order to keep things clear and safe, ZMS has put all of the tube rolling options in a handy Google sheet. You can find that sheet here.

I myself have been running the Aegis with different tube sets including the original, but I have finally settled for the following: RFT EL34s, Sylvania 6SL7GT and a General Electric 5R4GYA or Mullard CV593.

If you’re not into tube rolling but you want to try better tubes, you can buy an optional tube package from ZMF. It is called the TAD Bundle and it contains a 5u4G rectifier, a pair of KT-88 power tubes and a set of NOS 6N9S input tubes. This set goes for $199.99 USD.

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