Introduction to the Feliks Audio Envy Susvara Edition
Our journey with Feliks Audio started in 2017 when Paweł approached them at CanJam London. However, the real fun started at the 2022 Munich High-End show. Paweł met Feliks brothers there and listened to their flagship amplifier Envy. It was paired with many High-End headphones, but for some reason, there was no HiFiMan Susvara at their booth. Fortunately, HiFiMan is more than happy to share one of their Susvara with Feliks for the show. After a couple of minutes of listening, Paweł and Łukasz Feliks knew that this pairing was something extraordinary.
Three years after this meeting, in 2025, at the last High-End show in Munich, I had an opportunity to listen to the fruit of the cooperation of two incredible manufacturers. Moreover, I was able to steal for a review the first and so far the only produced Feliks Envy Susvara Edition. It’s a fine-tuned Envy with even more power that perfectly matches the requirements of HiFiMan Susvara. Shortly speaking, this combo brings listening experience to the next level, but more on that later, because now I would like to focus on other important features.
Packaging
When you’re lucky enough to earn that much to afford the reviewed Feliks Audio Envy Susvara Edition, you probably won’t want to challenge your luck anymore. Particularly during the amplifier shipment. Fortunately, the Feliks Audio team knows the reality, and the Envy arrives in a tremendous, nearly bulletproof box with special foam inserts. The amplifier itself is wrapped in a cloth, which additionally prevents it from being scratched.
In the box apart from the reviewed Feliks Audio Envy Susvara Edition, there is a power cable, a manual, tube guards, and tubes. Well, strictly speaking, there aren’t any tubes, but two PsVane CV-181 driver tubes and THE 300B power tubes made by Stradi. To be more precise, the power tubes are Korean-made Stradi S300B.
Even though S300B is compatible with the original 300B tubes made by Western Electric, it’s a completely different design. Thanks to the changes in the design, the tubes provide a more refined sound. It’s a product that is being claimed as a product superior to the FullMusic 300B tubes that are provided with Envy performance.
Design and Tech in Feliks Audio Envy Susvara Edition
Let’s state it here – using a tube amplifier is a commitment, tubes need to warm up before listening, during listening, they waste a lot of energy and turn it into heat, and usually the amplifiers are bigger than solid state substitutes. However, tested Feliks Envy Susvara Edition is a step further. It’s huge, produces ridiculous amounts of excessive heat, and it’s heavy as hell.
The regular Envy was already a solid piece of furniture, and the Susvara Edition has more powerful transformers, so the black box covering them in the rear end of the amp is even bigger. Another thing worth mentioning is that the Envy SE wenge wood finish matches the one present on HiFiMan Susvara housings.
When talking about the design and HiFiMan Susvara connections, I can’t miss one important thing – the gain selector. In the initial batch of Envy instead of gain, there was an impedance selector. For many users, it could have been confusing. For example, even when the amp was used with medium or low impedance planar headphones, like Susvara, which has only 60 ohms of impedance, the initial thought was to set it to medium impedance. However, since Susvara needs a lot of juice, the headphone did its best at the high impedance setting. When the impedance switch was replaced with a gain switch, you might have thought they couldn’t make it more obvious, but you couldn’t have been more wrong. In the Feliks Envy Susvara Edition, the gain switch has three positions.
Low gain – good for low-demanding headphones. It sounds like it’s made for headphones like HiFiMan Arya Organic or HE1000 Unveiled.
Medium gain – there is excessive power for Meze Elite or Susvara Unveiled, but it’s nice to have it.
And the last one – THE Susvara gain. Now, guess which headphones ought to be driven at that power. I can only say that Envy on that setup has all the power you need. At that setting, Susvara can become a speaker. I checked it on a loaned Susvara, so you don’t have to try this on your own, particularly when wearing the headphones. (Seriously, don’t do that. That level of loudness can irreversibly damage your hearing). Shortly speaking, I love the Lo/Mid/Susvara gain switch, not only is it more descriptive than ever, but also when switched to the highest setting, it’s sooooo powerful.
Now let’s focus on the tech. Paweł, in his review of the OG Feliks Envy, already wrote a lot about the internals of the amplifier, so let me write some important facts about the Envy Susvara Edition. It’s a class-A single-ended transformer, balanced amplifier. What it means is the purest and simplest way to implement a headphone amplifier.
What’s important, simple doesn’t mean easy, that’s like in cuisine. Tastiest meals are usually simple, but require a lot of knowledge and the best ingredients. Similarly, here, Mr. Henryk Feliks and his team design amplifiers using the best available electronic components, creating a Michelin-star meal for the most demanding audiophiles.
Sound of the reviewed Feliks Audio Envy Susvara Edition
Usually, when reviewing audio gear, I don’t only listen to it before, but also during writing the review. Particularly when writing about the sound, however, this time I need to make an exception.
The sound of HiFiMan Susvara plugged into the reviewed Feliks Audio Envy Susvara Edition is incredibly engaging. This happened a couple of times – I opened the document to write something, played music, and figured out that I had listened to the whole album and didn’t write anything. Just be aware that if you’re looking for gear to listen to background music, the bundle is a terrible choice. Perfect detail resolution and the amount of the texture reproduced by Susvara, paired with the power generated by Envy SE, can make even elevator smooth jazz an experience that keeps your complete attention.
After this short digression and 40-minute listening session, let’s get back to the sound of the Feliks Audio Envy Susvara Edition. But when writing about sound, I need to emphasize this once again. Regular Envy is already a powerful amp, but the Susvara Edition is a desktop power plant. It has plenty of headroom to run any headphone on the market. I’m using Goldenwave Serenade to feed the amp. Fine, it’s hot on a balanced line out. However, for most of the time I listen to music with Susvara, the potentiometer of Envy was at around 10%. I could crank it up even further, but that would be very exhausting.
Moreover, the way it drives Susvara at lower and medium loudness is incredible. Due to Envy SE’s power, the sound reproduction is effortless, and the dynamics are more than decent. I’d compare it to driving a Rolls-Royce. The V12 under the hood has plenty of power, but you don’t kick the pedal to the metal each time starting from a traffic light. The Envy SE gives you similar luxury, allowing you to waft through the music. However, at any point, you can just turn the volume knob clockwise, and any headphone will start shaking on your head.
Let’s start with a bass of tested Feliks Envy Susvara Edition, and that’s a hell of a BASS. Usually, when you think about tube amplifiers, you expect warm and smooth sound covered by a blanket. However, the reviewed amplifier paired with HiFiMan Susvara provides ridiculously well-controlled bass. When you expect a punch in a tune, the setup provides all the punch you can imagine. When the bass is required to be rich and dense, the amp delivers it, and when it needs to be crispy, it is indeed crispy. Some people would say the Susvara headphone is midrange-based with limited bass response. But with Envy Susvara Edition it becomes the ultimate headphone – complete one with perfect bass response.
The perfect match of Feliks and HiFiMan motivates me to take a shortcut in the review, but as a nonconformist reviewer, I need to mention how it pairs with other headphones. It’s because let’s be honest, if you’re going to spend €13 000 for an amplifier, you probably have already lost your sanity, and like me, you have some other incredible high-end headphones. So let me mention that the ridiculous amount of power makes Envy SE a perfect amplifier to drive any high-end headphones. A particularly good example is Meze Elite. It can be driven by almost any amplifier, but it scales a lot with better amplification. And when paired with Envy, it has all the power in the world. Thanks to it, the bass is getting much more engaging.
Now let’s move to the midrange. I could write about details, texture, or the overall quality of the sound, and yes, these are important areas to focus on… When reviewing Chinese amps priced at $100. When we talk about a €13 000 audio masterpiece, I can write that it’s just perfect. Impressive texture, so I can easily hear each movement while pulling the bow across the strings. Perfect details but with an optimal amount of warmth, so even while listening with HiFiMan Susvara, the sound isn’t too extreme for long listening sessions. Vocals are very intimate, with perfect positioning. Let me rephrase it once again – in terms of technicalities, the sound is just perfect, but at that price level it’s more than expected.
Without a doubt, mids are the strongest part of any amplifier based on 300B tubes. The S300B, due to its construction, sounds more neutral, but if you’re familiar with the characteristic timbre of 300B tubes, you will hear it here. For people who didn’t have an opportunity to listen to any amplifier based on these tubes, the 300B introduces some magic into the sound. It’s not a life-changing experience, but later on, you will easily point out an amplifier based on the tube.
If you have experience with good-quality headphone amps, you probably won’t discover anything new in the music you used to listen to, at least in terms of the sound quality. You probably can’t find anything more precise than some SMSL or Topping amps based on THX circuits. It’s just a device that is completely transparent and pure as water. However, Feliks Envy SE can deliver the music in a way that your ears and brain like much more. 300B tubes introduce some flavours that strengthen the impact of the midrange. That’s like herbs and species. It could overwhelm the sound, but thanks to the perfect balance, it just enriches the sound with incredible timbre.
Now let’s move to the treble and don’t blame me for soiling everything, but its performance is exemplary, with absolutely no flaws to speak of. It maintains a perfect balance, avoiding being overly sharp or too subdued, and consistently delivers a clear, unmasked sound. This makes for an ideal listening experience.
Let’s keep in mind that the reviewed amplifier is designed for HiFiMan Susvara. What does it mean? Even well-driven Susvara enlightens every detail, each sparkle, and any harshness in the treble. It’s a hard thing to build an amplifier that will properly drive Susvara in the bass and midrange, but keeping the treble under control… Huh, that’s another pair of shoes. With most amplifiers, Susvara is so extreme and exhaustive that you just can’t listen to it for long. But yet again, with Envy that was designed to match with Susvara particularly well, that’s another level. You can hear everything, but each sound is perfectly balanced. When listening to cymbals
I know I’m repeating myself, but reviewed Feliks Audio Envy Susvara Edition is just another level when it comes to how the headphone amplifier can deliver the treble. The sound quality is just present, and as a listener, you don’t think about it. What’s most important is the effortlessness with which it can push the Susvara headphone. A frequency that instantly shows the lack of power is obviously the bass. A solid kick requires a solid amount of power. However, the power is as important to reproduce the highest of the audible frequencies. And with such a power reserve, Envy SE can do with Susvara whatever an artist intended.
Now, the last part of the sound review, but certainly not the least. The soundstage is (yet again) basically perfect. It has tremendous depth and width with great layering, very precise localization, and separation of sound sources.
For me, the original Envy was a benchmark in terms of soundstage. I couldn’t find anything that would outperform it in terms of the soundstage while keeping overall good sound quality and being a good all-rounder. Well, I couldn’t until now. Feliks Envy Susvara Edition, paired with the Susvara headphones, is a particularly incredible combo. It provides a soundstage imaging and overall lightness of the sound, almost as impressive as the HiFiMan Shangri-la Senior system, while also delivering elements beyond soundstage and detail. Additionally, when buying the Envy SE bundle over the Shangri-la Sr. system, apart from the amp and headphone, you will fit a proper car in the budget.
But let’s get back to the Soundstage, because it’s incredibly impressive. When listening to Riverside by Agnes Obel, the vocalist is in the foreground, close to me, but she isn’t singing from inside my head. At the same time, instruments produce a layered and vibrant background, which is an incredible complement to the composition.
It’s hard to describe how impressive the soundstage is, but I will try to summarize it in one sentence. Solid-state amplifiers are impressive nowadays, but overpowered tube amplifiers bring the listening experience to a completely different level.
Comparison with Feliks Audio Envy Performance Edition
The whole review is kind of a comparison with the original Envy, because we have already reviewed it, and I feel the Susvara edition is more like an evolution of the original Envy, rather than a brand new product. But let me state the differences more explicitly.
Feliks Audio Envy Performance Edition is already a beast. It easily drives any headphones available on the market, with perfect control and gorgeous sound. It’s being sold with PsVane CV-181 mk2 driver tubes and the legendary Full Music 300B power tubes. The Susvara Edition comes with the same carefully selected driver tubes. However, the power tubes had been replaced with an even more prestigious, Korean-made Stradi S300B.
The build quality of the OG Envy has already been superb. Even though it was the first step of the relatively small manufacturer from Poland to the Summit-Fi league, they nailed it. From the outside, Susvara Edition has undergone a minor facelift. The cover is bigger, the volume knob chassis has a different design, wooden legs have been replaced with metal ones that are prepared to be placed on spikes, and what’s most important, but I’ve already mentioned it – the gain selector doesn’t have Hi gain anymore, now it’s Susvara gain.
The bass is perfectly controlled by both of the amps. The main difference is that the Envy Susvara edition has a better definition of the punch, while the Performance Edition is more relaxed. Hard to say if it’s because of better tubes or more powerful transformers, but that’s a step forward.
The midrange is very similar in both amplifiers. Each delivers a perfect amount of texture to the instruments’ sound. Vocals are engaging and emotional. I can hardly find any significant difference. The most relevant one is that, yet again, the Susvara Edition has more dynamics, while the Performance Edition is smoother.
When I think about the treble of most of the tube amps, instantly comes to my mind darkness, lack of detail, laziness, and an overly significant disadvantage when compared to the solid state amplifiers. HOWEVER, when it comes to the treble of the Envy, it’s completely different. The presentation of the high tones is crystal clear. Both amps and the Susvara Edition in particular beat almost everything I used to listen to.
Now it’s time for the soundstage, and all I can write about is the Envy Performance Edition one – it’s exceptional. Positioning of the sound sources is perfect. It’s wide, deep, and high as it should be in a perfect Summit-Fi headphone amp, nearly impossible to beat. But well… I don’t know what Mr. Henryk Feliks did and how he did this, but the Envy Susvara Edition provides the soundstage that is significantly bigger, while keeping everything perfectly positioned like in the OG Envy.
When starting this comparison, I was thinking it would be hard to find areas where Susvara Edition will be different, and I still think both are close to each other in terms of tuning and performance. When listening to the Envy Performance, I thought that was the ceiling of tube headphone amplifier performance. However, unfortunately for our wallets, the team of Feliks Audio took a tremendous hammer and wrecked this ceiling. What’s even more impressive is that they do this by improving their existing product, and this makes me even more excited to wait for their next releases. Especially after this year’s High-End Munich, I know they are cooking something new, so stay tuned, because we will surely write about it in the future.
Feliks Audio Envy Susvara Edition review – Summary
The Feliks Envy performance was already an impressive summit-fi headphone amplifier. With Envy Susvara Edition, they brought it to a completely different level where I can’t find any serious competitors apart from some niche boutique makers.
If you’re wondering if it’s worth it to pay €13 000 for a headphone amplifier, I can share my honest opinion that it’s totally not worth it. Mostly because of that, you can get the amp and HiFiMan Susvara in a bundle for €16 000. So if you already have HiFiMan Susvara, it may not be the best deal. However, if you’re thinking about buying a Susvara and an amp that can drive it, this can be a good offer for you. Because Susvara costs now €6900, after all, you will probably end up with Envy performance, which costs nearly €7000, which totals up to almost €14 000. And to be honest, if I had to choose, I would love to have the excessive power of the Susvara Edition, just in case I would like to drive speakers with a headphone amplifier. The bundle of HiFiMan Susvara and Feliks Envy Susvara Edition is, in my opinion, the best currently available in the market, and I highly recommend considering it as your next audio gear purchase.
Big thanks to Feliks Audio for loaning us the Envy Susvara Edition for this review. I wasn’t paid or asked to say anything good or bad about this product, all of the above is just my personal, unbiased opinion.
I’m a 24 years old software engineer, but also coffee, wine, and audio gear freak based in Cracow, Poland. I like to get lost in the city, but I hate getting lost while reading pompous audio reviews. My goal is to provide simple and informative reviews that I hope will help you to find your way around the rabbit hole.
