Review: Unveiling the HIFIMAN EF600 DAC Headphone Amplifier's Popularity

Some time ago, I heard many people in the audio community say, “I have ‘wooden ears’ and can’t tell the difference in headphone quality; I just listen for the fun of it.” Until one day, while waiting for someone, I was bored and bought a pair of headphones from the supermarket. The sound quality shocked me greatly. I never thought I could discern good from bad sound quality; it was just that my previous headphones had spoiled my ears. After that, I started experimenting with various headphones because, while my income allows it, treating my ears well is quite a romantic endeavor. The HIFIMAN EF600 DAC headphone amplifier caught my attention.

In my home life, I had been contemplating whether to buy a high-quality speaker or a headphone, or perhaps what device to pair with my current headphones. After much thought, I decided the third option suited me best, so I purchased the EF600 DAC headphone amplifier. Its purpose is to enhance the output power of headphones, as often relying solely on headphones makes it difficult to achieve high power output. My headphones are good, but their performance didn’t meet my expectations. Getting the EF600 was a wise choice.

From the product’s appearance, the EF600 DAC headphone amplifier has two highlights: one is the control interface, which includes all functions such as balanced output, high/low gain OS/NOS sampling, USB/coaxial input, etc. The control panel’s indicator lights show the operating status, and you can select the corresponding function by pressing the buttons for the left and right functions. The other highlight is its overall structure, which can fully support the headphones; with this headphone amplifier, I no longer need to buy a headphone stand.

Music enthusiasts usually have several different headphones; at least I do. One important reason I chose this model is that it has two headphone jacks: a common 6.35mm headphone jack and a XLR headphone jack. This headphone amplifier is perfectly compatible with both types of headphones.

The front panel design is very recognizable and aesthetically pleasing! The main functions are divided into two categories: sound output and audio source input. These two categories of functions are placed on the left and right sides of the display panel, and you can directly use the buttons below the information display panel to select the corresponding information, making it easier to operate. I usually use the High Gain NOS mode because it provides the purest and most transparent sound, and no other settings are required, making it even simpler to use.

In fact, the EF600 can be seen as an additional power amplifier between the audio source and the headphones. Once added, it can fully express all the details in the music. From the design stage, it was considered that there would be multiple audio source inputs, so the back panel is equipped with a Bluetooth receiver, a Type-C input port, a USB-B input port, and XLR balanced left and right input ports, etc., supporting all types of audio source inputs.

The EF600, as a headphone amplifier with decoding capabilities, adopts the latest “HYMALAYA Pro R2R DAC” module, which not only has lower distortion, lower noise, and extremely low power consumption but also features a newly designed high-current amplification circuit that optimally decodes and amplifies the input audio signal. Combining these two functions results in better output performance.

For some consumers, the belief that achieving good sound quality is far from them is due to the difficulty of tuning and debugging; they find it hard to learn. However, this is not the case. Except for professional tuning and debugging equipment, any product aimed at the general consumer market that requires a very high entry threshold has design issues to some extent. The EF600 considers this point; in its design, for example, with Windows and Mac systems, the decoding process requires no manual intervention, and most scenarios can achieve full automation.

Another consideration for audiovisual equipment has always been the size it occupies. After all, my workspace is limited; if such devices are too large, they will inevitably affect my normal entertainment and work. One reason I chose the EF600 over professional speakers is this: the bottom dimensions of this device are only 165mm x 104mm, making it more compact and not cramped in your space.

Additionally, its minimalist design can match various surrounding scenes; it can even serve as a piece of desktop decor, integrating well into the home environment, looking better the more you see it.

Many friends, like me, also pay attention to the product’s heat issue, especially for headphone amplifiers, where the circuits are larger and more complex, especially devices configured with high-power coils and high-current amplification circuits, which will generate more heat. Fortunately, this product has a good solution; it places the heavier components, such as the toroidal transformer, at the bottom for more stability. The overall circuit structure is located in the middle and upper position, and the heat generated is directed upwards and expelled, thus avoiding heat accumulation and ensuring better heat dissipation, leading to more stable operation.

I personally feel it’s necessary to remind you that the final output still relies on the headphones. If the headphones you are using cannot keep up with the performance, the EF600 will not help. You need to ensure that you have a pair of headphones that perform adequately or even well. Also, keep in mind that HIFIMAN specializes in various professional headphones; if you want to fully experience this headphone amplifier, you could also switch to their headphones.

From my experience, my previous headphones could already output music at a high level, with only minor flaws. Adding the EF600 further enhanced the output sound quality and improved the detail representation in the music. For example, in Baroque-style music, without the headphone amplifier, the metallic texture of the harpsichord was somewhat lacking, but after adding it, the metallic quality of the harpsichord was perfectly showcased.

I usually listen to a lot of symphonies and pure music, and after getting into Genshin Impact, I became interested in various game music, especially excellent game music, which made me less concerned about vocal performance; I focus more on the layers of the music. With a NAS, I started connecting all my music devices, whether it’s my phone, laptop, or PC, allowing me to stream songs from my music library, and the EF600 made this easier. It features high-definition Bluetooth reception capabilities (supporting LDAC, aptX-HD, aptX, AAC, SBC, and other high-definition Bluetooth protocols), making it more convenient to use with smartphones, tablets, and laptops with Bluetooth functionality.

Listening to local lossless high-definition music with Foobar2000 is one of my favorite ways to enjoy music. After using the EF600, playing some of my favorite songs became very convenient. A piece called “Midsummer Night’s Dream” creates a scene of confrontation between a string ensemble and an electric guitar. Before setting up the headphone amplifier, this confrontation was weakened because the string instruments could only clearly present the violin, while the harpsichord and organ were insufficiently represented. After adding this integrated amplifier, all the instruments’ sounds became more distinct, showcasing a more intense confrontation, which I enjoyed more.

As for vocal music, my understanding is relatively shallow. I tried a few songs, and my impression is that the vocal parts became clearer, no longer sounding indistinct. I tried some music that interests me more, such as: “Cicada Song: The Short Life of Light and Darkness,” “Cicada Song: The End of the Immortal Body,” and “Cicada Song: Long Life Without End.” These three pieces tell a story, inspired by the Dong people’s great songs in China, with each part having a distinct vocal performance. Among them, the section of “Cicada Song: The End of the Immortal Body” had a serious sticky quality in the vocal part without the EF600, as this part is known as the “Cyber Chanting” section with fast lyrics and little tonal variation. After the addition, the transparency was suddenly showcased.

For those who love listening to music, using a better set of equipment can greatly enhance the auditory experience. Here, with the headphones already performing well, adding a HIFIMAN EF600 DAC headphone amplifier can better showcase all the details in the music.