Hifiman EF400
The EF400 is a versatile all-in-one DAC and headphone amplifier featuring HIFIMAN’s proprietary Hymalaya R2R DAC module for digital-to-analog conversion. Its four-channel differential circuit includes a buffer, an active filter, and a high-current Class AB amplifier, delivering up to 4.4W per channel into 36Ω loads.
Connectivity options include a single USB input (supporting both Type-C and Type-B connectors), balanced XLR and single-ended RCA line outputs, and four headphone outputs: 4-pin XLR, 4.4mm balanced, 6.35mm, and 3.5mm. Users can switch between high and low gain settings, as well as choose between NOS (non-oversampling) and OS (oversampling) filter modes.
You can read the Hifiman EF400 review here.
Hifiman Hymalaya upgrade program
The EF400 comes equipped with HIFIMAN’s first-generation Hymalaya R2R DAC module. However, HIFIMAN has since released the second-generation Hymalaya Pro modules, available in three variants—Pro Gold, Pro Silver, and LE—each offering improved measured performance over the original.
Ranked by measured THD and dynamic range, Pro Gold offers the best performance, followed by Pro Silver, and then the LE. The LE modules are featured in the EF500, the Pro Silver in the EF600 and Serenade, while the Pro Gold is reserved for HIFIMAN’s flagship model, the EF1000.
HIFIMAN is currently offering an upgrade program that allows EF400 and Serenade owners to upgrade to the new Hymalaya Pro modules. The EF400 can be upgraded with either the Pro Silver or Pro Gold modules, while the Serenade supports an upgrade to the Pro Gold.
You can read the Hymalaya Pro Gold upgrade review here.
Upgrading the Hifiman EF400
DIY installation of the Hymalaya modules is not officially supported by HIFIMAN, and attempting it will void your device’s warranty. However, if you’re confident in your technical skills, you may consider doing it yourself, as the process is relatively straightforward and doesn’t require advanced electronics knowledge. You can try contacting HIFIMAN directly via email to ask if they’re willing to sell you the modules for self-installation.
Opening the EF400 is a straightforward process—just remove a few screws and lift off the top panel to access the internals. Inside, you'll find the DAC board with the original Hymalaya R2R module, which is socketed and secured by two small screws.
The board is already designed with reception points for the Pro modules, allowing for easy installation. Since I'm not particularly confident with a soldering iron, HIFIMAN kindly provided me with a new board that had pre-installed sockets.
From there, the upgrade was simple: I removed the old board and installed the new one, then easily socketed the Pro Gold modules. No soldering or special tools are required—just a basic screwdriver. One important detail to remember is channel placement: the module with the small green dot is for the right channel, and the one with the white mark goes on the left.
Audio stuff
For those who don’t own the HIFIMAN EF400—or simply don’t feel like reading the full review—here’s the key takeaway: the EF400 is known for its analog-like, natural timbre. It’s musical, melodic, and engaging, yet still offers a respectable level of technical performance and transparency.
That said, when compared to higher-end R2R DACs like the HIFIMAN Serenade or certain competitive delta-sigma DACs, the EF400 falls slightly short in terms of clarity and detail. Some listeners might also find it a bit too warm, lacking energy and sparkle, with a slightly rolled-off treble.
Upgrading to the Pro Gold modules addresses these shortcomings instantly. The EF400 Gold becomes significantly more technically capable, narrowing the performance gap while retaining its prized tonal richness and natural sound signature. The upgrade enhances detail, dynamics, and clarity—without sacrificing the musicality that makes the EF400 special.
The HIFIMAN EF400 Gold retains the same natural, organic character and minimal digital glare that made the original appealing, but now delivers a significant boost in clarity and transparency. Unlike the more subtle improvements observed when upgrading the Serenade from Pro Silver to Pro Gold modules, the transformation in the EF400 is far more immediate and pronounced.
Swapping in the Pro Gold modules elevates the EF400 to a noticeably higher level of technical performance—so much so that it feels like you’re listening to an entirely superior DAC/amp. A/B testing between the stock EF400 and the EF400 Gold is easy, as the chassis can be left open and the boards hot-swapped in just a few minutes. This makes the sonic differences unmistakably clear.
The EF400 Gold presents a cleaner, more transparent sound with a darker, quieter background and more refined, less grainy textures—especially in the treble region. High frequencies are better extended, and the overall presentation gains in depth, micro-detail, and resolution—all without sacrificing its musicality or veering into clinical territory.
One of the most striking improvements with the EF400 Gold is in the bass region, which becomes more textured, layered, and better defined compared to the stock EF400. In fact, this enhanced definition and articulation extend across the entire frequency spectrum. The Pro Gold modules also expand the soundstage, improving imaging precision and the separation of individual sound elements within the mix.
What makes this upgrade truly exceptional is that all these technical enhancements occur without compromising the EF400’s signature analog-like and organic timbre. The sound remains musical, expressive, and emotionally engaging, full of rich harmonics and tonal color. Listening to the EF400 Gold feels like a veil has been lifted—everything is clearer and more detailed, yet the presentation remains far from sterile or clinical.
Upgrade or not?
It's worth noting that not everyone may prefer the sound signature of the EF400 Gold upgrade. As is often the case in audio, personal taste plays a major role, and some listeners might actually favor the original EF400.
Compared to the Gold version, the stock EF400 offers a warmer and smoother treble, with a more relaxed and laid-back character. Its textures are fuller and richer, giving it a thicker, lusher feel. The bass carries more weight and body, and the soundstage, while less precise, has a more holographic and atmospheric quality. The treble, though less refined and slightly grainier, is softer and less forward.
Side by side, the EF400 leans toward a more retro, old-school tube-like sound, while the EF400 Gold presents a cleaner, more modern and technically polished performance. Ultimately, the choice between them will depend on your sonic preferences.
Conclusion
Upgrading the HIFIMAN EF400 with the Hymalaya Pro Gold (or Silver) modules is a cost-effective way to significantly enhance its technical performance while preserving its prized analog-like and organic timbre.
For a relatively modest investment, the EF400 is transformed into a more capable and refined device—one that stands out as the only truly affordable R2R DAC capable of competing with far more expensive models from HIFIMAN and other brands. It offers listeners a genuine taste of high-end R2R sound at a fraction of the cost.
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The Hifiman Hymalaya Pro Gold modules were kindly provided free of charge in exchange for an honest review. I don't receive monetary compensation and I don't use affiliate links.
The HIFIMAN EF400 upgrade program is priced at $149 for the Hymalaya Pro Silver modules and $299 for the Pro Gold. Currently, the program is available exclusively to EU customers and requires that you already own an EF400 unit. To complete the upgrade, the device must be shipped to a HIFIMAN service center for installation. You can read more information and buy the upgrade in Hifiman official store.
Disclaimer: For various Google indexing reasons, most parts of this review have been processed with an automatic paragraph rewriting tool. However it reads exactly the same as the original content that is available in my website.
The EF400 is a versatile all-in-one DAC and headphone amplifier featuring HIFIMAN’s proprietary Hymalaya R2R DAC module for digital-to-analog conversion. Its four-channel differential circuit includes a buffer, an active filter, and a high-current Class AB amplifier, delivering up to 4.4W per channel into 36Ω loads.
Connectivity options include a single USB input (supporting both Type-C and Type-B connectors), balanced XLR and single-ended RCA line outputs, and four headphone outputs: 4-pin XLR, 4.4mm balanced, 6.35mm, and 3.5mm. Users can switch between high and low gain settings, as well as choose between NOS (non-oversampling) and OS (oversampling) filter modes.
You can read the Hifiman EF400 review here.
Hifiman Hymalaya upgrade program
The EF400 comes equipped with HIFIMAN’s first-generation Hymalaya R2R DAC module. However, HIFIMAN has since released the second-generation Hymalaya Pro modules, available in three variants—Pro Gold, Pro Silver, and LE—each offering improved measured performance over the original.
Ranked by measured THD and dynamic range, Pro Gold offers the best performance, followed by Pro Silver, and then the LE. The LE modules are featured in the EF500, the Pro Silver in the EF600 and Serenade, while the Pro Gold is reserved for HIFIMAN’s flagship model, the EF1000.
HIFIMAN is currently offering an upgrade program that allows EF400 and Serenade owners to upgrade to the new Hymalaya Pro modules. The EF400 can be upgraded with either the Pro Silver or Pro Gold modules, while the Serenade supports an upgrade to the Pro Gold.
You can read the Hymalaya Pro Gold upgrade review here.
Upgrading the Hifiman EF400
DIY installation of the Hymalaya modules is not officially supported by HIFIMAN, and attempting it will void your device’s warranty. However, if you’re confident in your technical skills, you may consider doing it yourself, as the process is relatively straightforward and doesn’t require advanced electronics knowledge. You can try contacting HIFIMAN directly via email to ask if they’re willing to sell you the modules for self-installation.
Opening the EF400 is a straightforward process—just remove a few screws and lift off the top panel to access the internals. Inside, you'll find the DAC board with the original Hymalaya R2R module, which is socketed and secured by two small screws.
The board is already designed with reception points for the Pro modules, allowing for easy installation. Since I'm not particularly confident with a soldering iron, HIFIMAN kindly provided me with a new board that had pre-installed sockets.
From there, the upgrade was simple: I removed the old board and installed the new one, then easily socketed the Pro Gold modules. No soldering or special tools are required—just a basic screwdriver. One important detail to remember is channel placement: the module with the small green dot is for the right channel, and the one with the white mark goes on the left.
Audio stuff
For those who don’t own the HIFIMAN EF400—or simply don’t feel like reading the full review—here’s the key takeaway: the EF400 is known for its analog-like, natural timbre. It’s musical, melodic, and engaging, yet still offers a respectable level of technical performance and transparency.
That said, when compared to higher-end R2R DACs like the HIFIMAN Serenade or certain competitive delta-sigma DACs, the EF400 falls slightly short in terms of clarity and detail. Some listeners might also find it a bit too warm, lacking energy and sparkle, with a slightly rolled-off treble.
Upgrading to the Pro Gold modules addresses these shortcomings instantly. The EF400 Gold becomes significantly more technically capable, narrowing the performance gap while retaining its prized tonal richness and natural sound signature. The upgrade enhances detail, dynamics, and clarity—without sacrificing the musicality that makes the EF400 special.
The HIFIMAN EF400 Gold retains the same natural, organic character and minimal digital glare that made the original appealing, but now delivers a significant boost in clarity and transparency. Unlike the more subtle improvements observed when upgrading the Serenade from Pro Silver to Pro Gold modules, the transformation in the EF400 is far more immediate and pronounced.
Swapping in the Pro Gold modules elevates the EF400 to a noticeably higher level of technical performance—so much so that it feels like you’re listening to an entirely superior DAC/amp. A/B testing between the stock EF400 and the EF400 Gold is easy, as the chassis can be left open and the boards hot-swapped in just a few minutes. This makes the sonic differences unmistakably clear.
The EF400 Gold presents a cleaner, more transparent sound with a darker, quieter background and more refined, less grainy textures—especially in the treble region. High frequencies are better extended, and the overall presentation gains in depth, micro-detail, and resolution—all without sacrificing its musicality or veering into clinical territory.
One of the most striking improvements with the EF400 Gold is in the bass region, which becomes more textured, layered, and better defined compared to the stock EF400. In fact, this enhanced definition and articulation extend across the entire frequency spectrum. The Pro Gold modules also expand the soundstage, improving imaging precision and the separation of individual sound elements within the mix.
What makes this upgrade truly exceptional is that all these technical enhancements occur without compromising the EF400’s signature analog-like and organic timbre. The sound remains musical, expressive, and emotionally engaging, full of rich harmonics and tonal color. Listening to the EF400 Gold feels like a veil has been lifted—everything is clearer and more detailed, yet the presentation remains far from sterile or clinical.
Upgrade or not?
It's worth noting that not everyone may prefer the sound signature of the EF400 Gold upgrade. As is often the case in audio, personal taste plays a major role, and some listeners might actually favor the original EF400.
Compared to the Gold version, the stock EF400 offers a warmer and smoother treble, with a more relaxed and laid-back character. Its textures are fuller and richer, giving it a thicker, lusher feel. The bass carries more weight and body, and the soundstage, while less precise, has a more holographic and atmospheric quality. The treble, though less refined and slightly grainier, is softer and less forward.
Side by side, the EF400 leans toward a more retro, old-school tube-like sound, while the EF400 Gold presents a cleaner, more modern and technically polished performance. Ultimately, the choice between them will depend on your sonic preferences.
Conclusion
Upgrading the HIFIMAN EF400 with the Hymalaya Pro Gold (or Silver) modules is a cost-effective way to significantly enhance its technical performance while preserving its prized analog-like and organic timbre.
For a relatively modest investment, the EF400 is transformed into a more capable and refined device—one that stands out as the only truly affordable R2R DAC capable of competing with far more expensive models from HIFIMAN and other brands. It offers listeners a genuine taste of high-end R2R sound at a fraction of the cost.
-------------------------------------------------------------------------------
The Hifiman Hymalaya Pro Gold modules were kindly provided free of charge in exchange for an honest review. I don't receive monetary compensation and I don't use affiliate links.
The HIFIMAN EF400 upgrade program is priced at $149 for the Hymalaya Pro Silver modules and $299 for the Pro Gold. Currently, the program is available exclusively to EU customers and requires that you already own an EF400 unit. To complete the upgrade, the device must be shipped to a HIFIMAN service center for installation. You can read more information and buy the upgrade in Hifiman official store.
Disclaimer: For various Google indexing reasons, most parts of this review have been processed with an automatic paragraph rewriting tool. However it reads exactly the same as the original content that is available in my website.
