HMX FJ400 vs. HMX SU
An in-depth look at the HMX FJ400 and the HMX SU switches—which one is the best fit for you?
Overview
When it comes to selecting a mechanical keyboard switch, the HMX FJ400 and the HMX SU present appealing options for enthusiasts who prefer linear switches. The FJ400 is celebrated for its balanced sound profile, making it an excellent choice for those seeking a versatile typing experience that strikes a middle ground in the HMX Film switch lineup. In contrast, the HMX SU features a full PA12 housing and a T5 stem that contributes to a subtle yet relatively deep sound profile, appealing to users who appreciate a slightly richer auditory feedback. While the FJ400 offers a harmonious blend of sound and performance suitable for both gaming and typing, the deeper acoustics of the SU create a more immersive experience. However, let's dive in a bit deeper beyond generalities so you can best decide on the switch that will suit your preferences and needs.
By the numbers
Technical specifications
Actuation force
50g
Actuation force
45g
Bottom-out force
58g
Bottom-out force
50g
Pre-travel
2.00 mm
Pre-travel
1.80 mm
Total travel
3.80 mm
Total travel
3.60 mm
Factory lubed
Yes
Factory lubed
Yes
Stem construction
Standard
Stem construction
Standard
Stem material
T2
Stem material
T5
Top housing material
POM
Top housing material
Nylon
Bottom housing material
Nylon
Bottom housing material
Nylon
Mount type
PCB (5-pin)
Mount type
PCB (5-pin)
Spring
22mm single-stage spring
Spring
22mm single-stage spring
Housing materials
The HMX FJ400 and HMX SU keyboards utilize distinct materials for their top housings—POM for the FJ400 and nylon for the SU. The POM top housing of the FJ400 contributes to a unique sound profile that is described as deeper and more muted. This characteristic can be attributed to the hardness of POM, which allows for a certain resonance but limits sound projection compared to softer materials. In contrast, the nylon top housing of the SU is recognized for producing deeper and fuller sounds, primarily because nylon absorbs more sound due to its softer properties. Therefore, while both keyboards aim for a desirable sound profile, the FJ400 leans toward a more muted tone, while the SU offers a richer auditory experience.
Both keyboards share the same nylon bottom housing, which plays a significant role in shaping the overall sound and feel of the switches. The nylon material used in both the FJ400 and SU bottom housings ensures that users experience a deeper, rounder sound when typing, attributed to its sound-absorbing properties. Regardless of the differences in the top housing materials, this commonality in the bottom housing indicates that both models can achieve similar results in terms of sound profile when the keys are pressed down. The dampening effect provided by nylon in either switch enhances the typing experience, allowing for a comparable sensation and auditory feedback.
Overall, the differing top housing materials of the FJ400 and SU demonstrate how the choice of plastics affects the auditory dynamics of each keyboard. While the FJ400 provides a more subdued and unique sound profile with its POM top housing, the SU amplifies the acoustic experience through its nylon top housing. However, with both models utilizing nylon for the bottom housing, the result is a consistently deep and full sound profile on bottoming out. This shared nylon characteristic ensures that, despite their different top housing experiences, the FJ400 and SU maintain a level of auditory coherence when it comes to their bottoms, giving users an enjoyable typing experience across both keyboards.
Weight
The HMX FJ400 and HMX SU linear switches exhibit distinct characteristics in both actuation force and bottom out force. The FJ400 requires an actuation force of 50 grams and has a bottom out force of 58 grams, placing it in the medium range. In contrast, the SU switch is lighter, with an actuation force of 45 grams and a bottom out force of 50 grams, categorizing it as a light linear switch. This difference in force may appeal to different types of users; the lighter SU switch is ideal for those who prefer a more effortless typing experience during long sessions, while the FJ400 might be favored by users who enjoy a more substantial feel with its heavier forces. Therefore, while both switches generally fulfill the role of linear actuation, the FJ400 offers a firmer feel compared to the lighter and more responsive SU switch.
Travel distance
The HMX FJ400 linear switch has a travel distance of 3.8 mm, while the HMX SU linear switch features a slightly shorter travel distance of 3.6 mm. This difference of 0.2 mm positions the FJ400 as a better option for those who prefer a more substantial keystroke, while the SU may appeal to gamers and users who favor quicker response times due to its shorter travel distance. As shorter travel distances have become increasingly popular for their responsiveness, selecting the SU would likely yield a more immediate tactile experience. Conversely, those who appreciate a more pronounced keystroke might find the FJ400 more satisfying. Overall, the choice between the two switches will depend on individual preferences for key feel and response time.
Price comparison
Which switch is more bang for your buck?
The HMX FJ400 has an MSRP of $3.50 per 10 switches. At Milktooth, we are able to pass on savings to our customers and offer the FJ400 for $3.29.
The HMX SU has an MSRP of $3.50 per 10 switches. At Milktooth, we are able to pass on savings to our customers and offer the SU for $3.29.
Here at Milktooth, we offer the best prices on switches (on average, 27% lower the competition). In addition, we offer free shipping on orders over $49.00. We also offer free returns and exchanges, so you can shop with guaranteed satisfaction.
That said, while price is an important piece of the puzzle, our opinion is that you should ultimately pick the option that most suits your unique preferences since you’ll be using these switches for years to come. In other words, finding something perfect for you is, in our view, the most important criteria.
Typing experience
The HMX FJ400 linear switch is recognized for its balanced sound profile, making it an appealing option for users who prefer a more moderate auditory feedback while typing. In contrast, the HMX SU linear switch, featuring a full PA12 housing and a T5 stem, produces a subtle yet relatively deep sound. The differences in their sound characteristics can lead to unique auditory experiences; however, both switches can deliver satisfying results, emphasizing the importance of external factors like the keyboard build and keycap material, which can further enhance or mellow these sound profiles.
When it comes to feel, the FJ400 is positioned as a middle-ground option within the HMX Film switch lineup, suggesting it likely provides a smooth and consistent keystroke that caters to a wide range of preferences. Meanwhile, the SU switch's characteristics are less clearly defined, leaving an unknown in its specific tactile feedback. Despite the uncertainty with the feel of the SU, both switches can offer a rewarding typing experience, with the FJ400 likely appealing to those who appreciate a versatile tactile sensation.
In conclusion, while both the HMX FJ400 and HMX SU linear switches cater to different preferences in sound, with the FJ400 offering a balanced profile and the SU a deeper tone, they each promise a distinct typing experience. The feel of the FJ400 is recognized as smooth and adaptable, while the tactile qualities of the SU remain undefined. Your choice may ultimately depend on personal sound and feel preferences, and both switches offer excellent potential for a quality typing experience, contingent upon how they interact with your unique keyboard setup.
Conclusion
To conclude, when choosing between the HMX FJ400 and the HMX SU linear switches, consider your personal typing preferences and what you value most in a keyboard experience. If you prefer a medium bottom-out force that strikes a balance between responsiveness and the assurance of actuation, the FJ400 would be a solid choice. Its balanced sound profile and feel cater well to those who enjoy a consistent feedback while typing, making it ideal for everyday use and gaming alike. On the other hand, if you gravitate towards a lighter touch and appreciate a more subdued auditory experience, the HMX SU is likely the better option for you. With its lighter bottom-out force and relatively deep sound profile, this switch is perfect for users who prefer a softer keystroke for quieter environments or extended typing sessions. Ultimately, your choice should align with your typing style and the specific ambiance you want to create while using your mechanical keyboard.
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