MUB5 R2R DAC & Headphone Amp Firmware

Standard Firmware

MUB5-V1.0C2.hex

Factory Firmware & Default

MUB5-V2.6H1.hex

Release Date: April 2026
Changes:
1. Modified screen-off logic.  
   ① In LCD Close-off mode, pressing the power button to turn off the screen and can only be turned back on by pressing the power button; touch, buttons, and volume will not turn on the screen.  
   ② In LCD Close-30S mode, it remains the same as before: the screen can be turned off automatically or manually, and after the screen is off, it can be turned back on by pressing the power button, touch, buttons, or volume.  
   ③ Added automatic return to the main display page and lock on the main page after screen-off; touching the screen after screen-off will no longer enter the settings page.
2. Gain changed to four levels.  
   ① Original high gain changed to Super gain.  
   ② Added an intermediate level (high gain) between normal and super gain to allow for finer volume adjustment.
3. Lock key mode changed from two to four: ALL, NO VOL, NO Key, Touch.  
   ① ALL: Full lock.  
   ② NO VOL: Volume knob not locked.  
   ③ NO Key: Buttons not locked.  
   ④ Touch: Only touch screen locked; volume and buttons not locked.
4. Volume adaptation when switching gain.  
   ① After switching gain, the volume automatically adjusts to the closest possible loudness to the previous level to avoid sudden loudness affecting the user experience.  
   ② Original volume 0 remains volume 0 after switching.  
   ③ If switching to a higher gain results in volume 1 still being louder than the previous loudness, it will automatically adjust the volume to 0.
5. Gain switching changed to a pop-up window with four options.
6. Fixed the bug where "Runtime" in the "About" menu would randomly reset to zero.
7. Fixed the bug where selecting "BT" in "Input" or "LO" in "Output" would not automatically return to the main interface after 20 seconds.
8. Fixed the bug where switching gain in LO mode would sometimes be abnormal.
9. "Recovery" operation in the "About" menu no longer clears "Runtime".

MUB5-V3.3N7A.hex、MUB5-V3.3N7E.hex
Pure Firmware,Based on MUB5-V2.6H1
Release Date: April 2026
Differences from MUB5-V2.6H1:  
   1. Does not include item 9 from the MUB5-V2.6H1 upgrade, meaning that performing the "Recovery" operation in the "About" menu will still clear "Runtime". 
   2. Removed the "LCD Close" and "Auto off" functions that affect sound quality. They still appear in the menu, but no functions.  
   3. These two firmware versions differ only in sound style.

Firmware Download

202604 Firmware Package (including V1.0C2, V2.6H1, V3.3N7A, V3.3N7E; The PC software required for the upgrade, The upgrade instructions file)
MUB5...-Package_202604.rar (170MB)

202604 Firmware（V1.0C2、V2.6H1、V3.3N7A、V3.3N7E）

If the download speed is very slow, it may be due to too many people downloading at the same time, causing server bandwidth limitations. You can try again after waiting a few hours (download during off-peak hours).  

Clark Listening Impressions

V1.0C2: The sound is lively, smooth, with a strong sense of presence. It sounds good and is easy to listen to for extended periods, very comfortable. It has high tolerance for system pairings, and it sounds great with whatever headphones you use. (Suitable for 90% of users who drive headphones directly.)
V2.6H1: Compared to V1.0C2, the horizontal soundstage is wider, with more sonic details, greater transparency and accuracy, and better vertical layering. Simply put, the sound quality has improved noticeably, but it also demands more from system pairings and may not necessarily sound better.
V3.3N7A: Sound quality is further improved upon the foundation of V2.6H1. It is delicate and refined, more transparent and layered, with better micro-dynamics. But the same issue applies: higher sound quality does not necessarily mean it will sound better when driving headphones directly.
V3.3N7E: The V3.3N7A above sounds slightly serious and lacks a bit of liveliness. The V3.3N7E sounds more lively, more passionate, with further enhanced transparency. The quality is very high, but it is a bit stimulating and not as easy to listen to for extended periods.

If you are using the MUB5 as a pure DAC, higher sound quality usually sounds better, and the ranking might be V3.3N7E ≈ V3.3N7A > V2.6H1 > V1.0C2.

However, if you are using the MUB5 to drive headphones directly, it may not necessarily be the case, as it also depends on the pairing. During A/B comparison, the ranking might still be the same as above, but when listening to music alone, V1.0C2 might be the most comfortable, the most moving, and the most listenable. At least I (Clark) still very much like V1.0C2 when paired with most headphones.

Upgrade Recommendations

1. The upgrade process is relatively complex and requires a computer. It is only suitable for users who enjoy play.
2. Higher sound quality does not necessarily mean it will sound better. This depends on the pairing and the upper limit of the headphones. V1.0C2 may still be the most suitable for you.
3. There is no sequential order for upgrades. After upgrading, you can upgrade to the factory firmware V1.0C2 at any time.
4. Because the sound after upgrading may not be suitable for you, friends who do not have the conditions to repeatedly upgrade and compare are not recommended to bother with it.