The Hifiman Hymalaya Pro Gold modules where kindly provided free of charge in exchange for an honest review. I didn’t receive monetary or any other kind of compensation and I don’t use affiliate links. To learn more about the prices and the availability of the Hifiman Hymalaya upgrade program please click here.
Hifiman Hymalaya R2R DAC module
The world famous Hifiman brand is mostly known for their diverse range of planar magnetic headphones but they also make high quality electronic components, like the HIFIMAN EF400 and the Serenade DAC/amps. What differentiates Hifiman from most of the competition is that they use their own designed R2R DAC module to do the digital to analog decoding rather than relying on various D/S DAC chips. They call this module the “Hymalaya” and has now reached its second generation that is named “Hymalaya Pro” and features many significant improvements over the first.
The Hymalaya DAC module is essentially a tiny R2R DAC made from a great number of discrete resistors with 0.01% precision. The second generation of the module uses a new FPGA with higher computing power than its predecessor. The FPGA runs a firmware with a new algorithm that produces higher accuracy with lower power consumption by 16% compared to the first generation. The module is also made with twice the number of resistor arrays versus the first generation and its overall efficiency is increased by 20%.
The Hifiman Hymalaya upgrade program
The Hifiman Hymalaya Pro module comes in three different versions; The Pro Gold, the Pro Silver and the LE, from the best to the worst when it comes to measured THD and dynamic range. The LE is used in Hifiman’s EF500 DAC/amp, the Pro Silver in the EF600 and the Serenade models while the Pro Gold is saved for their flagship DAC the EF1000.
Hifiman is now offering an upgrade program applicable to the Serenade and EF400 models and for European only customers. Owners of these devices can send them to Hifiman service center where they will be upgraded with the Hymalaya modules of their choice and then returned back with an extended one-year warranty.
The available options are to upgrade the stock Hymalaya Pro Silver modules of the Serenade to Pro Gold for $149 and the stock first generation modules of the EF400 to the Pro Silver for $149 or even the Pro Gold for $299.
A DIY installation adventure of the Hymalaya modules
Disclaimer: Hifiman does not officially support DIY installation of the Hymalaya modules and the only valid way to do the upgrade is to send your device to the company.
Long story short; After observing that the Hymalaya DAC modules can be swapped without the need of any soldering work, I convinced Hifiman that I am skilled enough to perform the upgrade by myself. After all this was the only way to do a valid comparison because sending the Serenade for the upgrade and waiting it to return back would need about a month, a period of time enough to erase any acoustic memory.
Since this procedure is not officially supported by Hifiman, I am not going to describe it in full detail. Let’s say that it is a pain in the ass to open the chassis of the Serenade and take the circuit board out of it. People that are skilled and careful enough can do it but there is always the risk of damaging the board or cutting a connector cable.
After you manage to take the guts of the Serenade out, replacing the two Hymalaya modules is a child’s play because they are plugged into the main board just like socketed op-amps. The only thing you have to do is to remove the security screw in each module and then swap it with the new one while carefully observing the matching color of the small indicator dot. Then you must carefully take everything back to place and you are done.
A side note regarding the Hifiman EF400 upgrade
The Hifiman EF400 is very easy to open, just remove six screws and the lid, but very difficult to do the upgrade. While the first generation Hymalaya module is socketed to the board and can be easily removed, installing the two Pro modules requires unsoldering the old sockets and soldering four new ones at the places that you can see marked in the following photo. So while I had two spare Pro Silver modules that i removed from the Serenade, i could not perform the upgrade and test the sound performance.
However, judging from the sonic improvements that the Pro Gold Hifiman Hymalaya modules brought to the Serenade, I bet that upgrading the much inferior first generation modules of the EF400 will yield even greater sound enhancements.
Comparison methodology
From the upgrade procedure as described above, it gets perfectly clear that a side by side comparison and A/B testing of the two different Hymalaya modules is not possible.
My methodology was to use the Serenade for a couple of days in order to get acclimatized with its sound signature again. At D-Day, I listened carefully to a small selection of very familiar tracks and took notes. Then I swapped the modules and did the same immediately afterwards. In the end I spent another couple of days with the Serenade and the new modules doing some leisure listening.
For the comparison I used the Hifiman HE1000 Stealth headphones with a Lavricables upgrade cable.
Listening impressions
The Hifiman Serenade is an exceptional sounding DAC/amp, and one of my favorites if that matters, as it combines a natural and organic timbre with excellent technicalities and transparency for an R2R DAC. It has analog-like sound characteristics with spades of musicality and complete absence of digital artificiality. Melodious and engaging, it is a fine example of the unique R2R sound signature without compromises in technicalities.
Swapping the Pro Silver Hifiman Hymalaya modules for the Pro Gold does not yield any night and day differences but rather a bunch of small, yet easily discernible and well valued improvements that get combined together to elevate the overall sonic performance.
The first thing to note is the sense of extra silence. In the already quiet Serenade, the background of the music becomes even blacker allowing the finest details to emerge from the depths of the recording and surface in a natural and non analytical way, adding greatly to the overall realism of the music. (Given that you don’t use too sensitive headphones, otherwise you will hear the transformer to hum a little)
The upgraded Serenade gains in transparency and fidelity as well as in clarity and definition. It sounds more refined and resolving while you can focus deeper inside the recording. The soundstage expands to become more holographic and immersive with extra layers of depth and improved imaging accuracy.
More listening impressions
All these technical enhancements happen without affecting the exceptional timbre realism and the well valued musicality of the Hifiman Serenade. The sound retains its organic and analog character as the Pro Gold modules do not make it clinical, sterile or add any kind of digital artificiality. On the contrary, the Serenade becomes even more lifelike and musically convincing than it was before the upgrade.
If there is a side effect, is that when upgrading to the Pro Gold modules there is a slight loss in sound density or note weight if you prefer. The textures become just a bit drier and lose some of their elasticity and lushness but the differences are rather minimal. However, minimal or not, the truth is that people who need or enjoy these kinds of attributes at their maximum quantity, and prefer the most dense and full bodied sound might want to stick with the Pro Silver modules.
In the end
The Hifiman Hymalaya upgrade program is a cost effective and very affordable way to enhance the sound quality of both the Hifiman Serenade and the EF400 DAC/amp models. Swapping the Pro Silver with the Pro Gold modules allowed the Serenade to reach the apogee of its technical performance while still sounding as natural and organic as in the first place, if not more. If you are lucky enough to be a European customer, where the upgrade service is available, don’t think twice and go snatch this amazing opportunity to greatly enhance the sonic performance of your Serenade or EF400 for just a good dinner’s worth.
Copyright – Petros Laskis 2024.
+ Improves technical performance without affecting timbre quality
+ Enhances resolution and refinement
+ The soundstage becomes more immersive
+ The background gains is silence
+ The timbre becomes more convincing and lifelike
+ Available for the Hifiman Serenade and EF400 models
+ Affordable and cost effective
+ The upgrade comes with one year warranty
- Not a do-it-yourself procedure
- Only available for EU customers
- Minimal loss in note weight and elasticity
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