Under the hood.

In the heart of 340m, similar to 340 and D16, you have a 1-bit discrete DAC controlled by an updated custom FPGA-Master 3.0.  To understand the DAC structure of 340m, I would like to revisit the evolution of its design, starting with the original FPGA-Master in the 320, which was implemented as an audio system controller to offload SoC processing by directly requesting audio data and by syncing and generating all audio clocks to reduce jitter.  In the D16 design, FPGA-Master 2.0 added functionality to generate PWM signals that drive discrete PWM-DACs for audio signal decoding.  As part of the 1-bit discrete DAC design, iBasso implemented 16 sets of cascaded 8E (8-Element) PWM-DACs, totaling 128 Discrete PWM-DAC elements operating in FIR (Finite Impulse Response) mode.  In the 340 design, the updated FPGA-Master 3.0 code was optimized further, adding a new exclusive Harmonic Setting adjustment.  340m stepped it up to 160 Discrete PWM-DAC elements, fine-tuning the technical performance to meet higher-level requirements for clock precision and new audio-processing algorithms.

You still have a dual-boot system design with access to either a full Android OS, which includes WiFi, BT, and the Google Play Store with unlimited app support, or a stripped-down, local playback-only Mango OS (Linux), which focuses strictly on audio performance without wasting OS resources on other tasks.  You can boot 340m in either of these modes.  Just like the 340, the 340m runs on optimized Android 13, Snapdragon 665, 8GB of RAM, and 256GB of ROM.  Also, 340m uses a similar to 340, 6” AMOLED display with 1080×2160 resolution, a new quality OLED display on par with today’s smartphones.  And you get Wireless Connectivity (Wi-Fi/Bluetooth) with Bluetooth V5.0, Wi-Fi 802.11a/b/g/n/ac, and dual-band (2.4 GHz/5 GHz) support.  For support, it covers native DSD512 and PCM 32-bit/768kHz, and supports the following formats: APE, FLAC, WAV, WMA, AAC, ALAC, AIFF, OGG, MP3, DFF, DSF, DXD, and DST.

You still have a dual-battery design, where 340m uses 2 (3200mAh) in series for an 8.8V analog circuit section, and 2 (3200mAh) in parallel for a 4.35V digital section.  Unlike their regular 340-series DAP, which uses a single USB-C charger for analog/digital batteries at a lower voltage, the MAX series uses a dual-charger system: the USB-C port charges a lower-voltage digital battery, and the DC-IN (12V) input charges a higher-voltage analog battery.  But at 340m, iBasso also implemented a DC-IN desktop Super Gain mode that bypasses the internal “analog” battery, powering the amp rails from an external 12V supply.  Obviously, there was not enough room for two separate 12V inputs; the DC-IN input combines both functions and uses the same charger.  Since DC-IN has to be next to the amp circuit, which is located at the top of 340m, where the 3.5mm/4.4mm PO/LO ports are, the DC-IN charging port is there as well.  USB-C port is located at the bottom, opposite of it, meaning that when charging both, the cables will be coming out from the top and the bottom.  Some might find it inconvenient, but there is a reason for the location of these ports, as described above.  And in theory, charging and using DC-IN mode are usually done at the desk, where I think people will be less picky about extra cables.  Of course, those who are not familiar with the MAX series of iBasso DAP will have to get used to 2 charging ports, and might find it useful to get a USB-DC adapter with a fixed 12V output (for PD USB chargers) and 5.5mm/2.1mm (outside/inside) DC tip, although a more common 5.5mm/2.5mm works as well.

Now, speaking of batteries, in my multiple tests with DAC and amp set in High Gain, with WiFi/BT off, using 4.4mm output, local playback in the loop (not burn-in cable, but actual IEMs), and the screen mostly off (just turning it on to check the battery status), I was able to get around 15.8 hours of playback time, usually with digital battery draining first. At the same time, there was still some juice left on the analog battery.  So, in theory, when you are out and about and have one of those slim, spare charging batteries for your smartphone, you can boost 340m to get a longer playback time.  Of course, you can also carry a dual-port PD portable battery charger and use the USB-C output directly to charge the digital battery of 340m, while using the USB-DC cable adapter from the same battery to charge the analog battery.

Also, while the 340m analog output is based on the amp18 card that was released for the 340 modular DAP, it wasn’t a copy-and-paste design.  The original amp18 is based on a two-stage amplification architecture, using 40 dual transistors to form an 80-transistor matrix.  340m upgraded the original amp18 design by adding a dedicated differential buffer-amp stage to achieve full differential transmission, significantly reducing noise interference and further isolating the rear-stage power output’s impact on the front stage.  According to iBasso, the headphone amplifier uses a 4-channel, fully differential architecture with a cascaded current-feedback design to address latency issues associated with deep negative-feedback circuits.  The output spec is quite impressive.

4.4mm Balanced PO:

• Output Impedance: 0.9Ω
• Output Level: 6.45Vrms@32Ω (Battery) / 8.48Vrms@32Ω (DC-IN)
• Output Power: 1300mW@32Ω (Battery) / 2250mW@32Ω (DC-IN)

3.5mm Single-ended PO:

• Output Impedance: 0.4Ω
• Output Level: 3.16Vrms@32Ω (Battery) / 4.27Vrms@32Ω (DC-IN)
• Output Power: 330mW@32Ω (Battery) / 570mW@32Ω (DC-IN)

 

OS/GUI.

As already mentioned, similar to DX2xx/3xx and corresponding MAXs, 340m also features a dual-boot system design, where you have access to either the full Android OS with its Mango audio app or the stripped-down Mango Linux OS, with the main interface being the audio app itself.  Each one has its advantages depending on the user’s requirements.  With full Android access, you have support for WiFi and Bluetooth, can install other apps, stream audio, etc., and, unlike 320m, 340m already comes with Google Play pre-installed.

Mango OS is a stripped-down operating system built around the Mango app interface, with a strict focus on audio performance and on avoiding the waste of OS resources on other tasks.  Switching between these two OS is very simple. When you boot up into Android and press’n’hold Power button, you have a choice of switching to Mango, Power off, or Restart. When you switch to Mango, DAP reboots and continues to boot into Mango OS every time. To switch back to Android OS, go to Settings and select Android System. Once the Android System is selected, it will boot only into the Android OS until you switch back to Mango OS.

During a full Android OS boot-up, 340m comes with an updated version of the Mango Player, v4.0.32.  There are a few differences between the Mango app and the Mango OS interface; they are not identical, and I will cover them later in the review, including differences in sound.

The view of the embedded song/album artwork, if one is available, looks good on the 340m 6” display, the same as in 340.  If embedded artwork is not available, a default image is displayed.  The main playback screen has a very logical layout: you swipe the artwork display left/right to skip between songs, and access song search and file management via a shortcut in the upper-left corner, and settings via a shortcut in the upper-right corner.  Another useful feature I appreciate is the 3-dot shortcut in the lower-right corner of the artwork window, which opens the Now Playing list of songs for scrolling.

Below the artwork, you have track info (bit/rate/format) and a scrub bar to advance through the song, where you can tap anywhere to skip.  In early versions of the Mango app, you had to tap and drag the current song position to a new one. Starting with v2, you can fast-forward or rewind by simply tapping on the timeline, as you would on your smartphone.  Unfortunately, this only works in the Mango app, not under Mango OS.  Below it, you have a shortcut on the left to view more detailed information about the song (including adding to the playlist or deleting it), and another shortcut on the right to switch between playback modes (play in order, repeat list, shuffle, repeat current song).  The Play/Pause and Skip next/prev buttons are large and located at the bottom.

In Music search and track management, you can search through your songs (since they are indexed) or browse the internal storage directory.  Under the indexed list, you can view All Music or sort by Album, Artist, Genre, Now Playing, and Playlist.  Any song you long-press will give you an option to Play, Add to playlist, or Delete.  You also have a setting (3 vertical bars at the very right) to specify exactly what you want to see in the navigation bar or how you want music to be sorted and viewed.  The level of customization details here is quite impressive.  Plus, at the bottom, you have a small area to view the currently playing song and control its playback with the play/pause button.  Tapping on it takes you back to the main Playback screen.

In the Settings Menu, you have access to Gapless (on/off), DC-IN Super Gain (when DC-IN input is plugged in), DAC Gain (L/H), AMP Gain (L/M/H), Play mode (order, loop, shuffle, repeat, folder play), EQ (on/off, which brings you to the Graphic/Parametric EQ screen), L/R Balance, Harmonic (H1 – original, H2 – natural, H3 – Even+, H4 – Odd+, H5 – All), Media Scan, Replay Gain, Normalization, USB DAC, Bluetooth DAC, Display Settings (with lots of customization options), Pause Timer, Clear Data, and System Info.

The Notification bar swipe-down is also helpful, as it lets you change Harmonics, AMP Gain, and DAC Gain, in addition to the usual WiFi, Bluetooth, and Auto-Rotate shortcuts.  You can configure which options you can see in the notification from a limited set, but I do wish they would include a shortcut to Audio Settings.

Mango app vs Mango OS

I’m sure many will be curious how the Mango app (in Android mode) compares to the stripped-down Mango OS.  Here is a summary of some of the differences I found while testing 340m.  There could be more, but these stood out for me.

• Mango OS startup is a little faster, while the Mango app/Android takes a little longer.
• Mango app (on Android) navigation is faster, while Mango OS has a slight lag.
• Mango app (on Android) has EQ and PEQ, while Mango OS has only EQ.
• In the Mango app, you can randomly tap on the timeline to advance to any part of the song; in Mango OS, you have to drag the pointer to a new position, like in the original DX200.
• In the Mango app, the “Now playing” directory/list is accessible when you click in the lower right corner of the artwork window, while in Mango OS, you have to tap the upper left corner to get to music sorting, where you view the “Now playing” list.

There are also differences in sound between the Mango app and the Mango OS, and I will cover them in the sound analysis section of the review.

EQ

340m offers a traditional Graphic EQ (EQ) with fixed frequency bands and a gain slider.  In the Mango app (Android mode), you also get Parametric EQ (PEQ), which gives you more control over which frequency is adjusted, the bandwidth of that adjustment, the type of filter used, and, of course, the gain of the adjustment.  Here are my observations while testing EQ and PEQ.

Graphic EQ (EQ)

• When enabled, it drops the volume to create extra headroom for band adjustment (to avoid clipping).
• Relatively clean 10-band EQ adjustment (33, 63, 100, 330, 630, 1k, 3.3k, 6.3k, 10k, 16k frequency bands).
• Whenever you adjust a band, you can see it being shown graphically above the EQ sliders- great visual feedback.
• 5 genre-specific presets are included (classic, pop, dance, rock, ACG), each of which can be adjusted further and reset to its original state.

Parametric EQ (PEQ)

• Includes 6 custom preset settings.
• When enabled, volume doesn’t drop.
• While adjusting, I didn’t hear any distortion.
• Each preset setting has 6 assignable filters/frequencies to shape the sound, where a different color on the screen represents each one.
• Filter types: low-pass filter, high-pass filter, band-pass filter, notch filter, all-pass filter, peaking filter, low-shelf filter, high-shelf filter – peaking filter will probably be the most useful.
• Each filter has: Fc (center frequency, from 33 to 16k), Gain (-20 to 20 dB), Q factor (0.3 to 20), where a smaller Q makes the bandwidth wider, and a bigger Q makes the bandwidth narrower.
• Fc and Gain could also be adjusted on the touch screen by dragging the pointer left/right and up/down.
• The sound is adjusted/updated in real time as you move the filter peak and frequency.

Page 3 – Sound Analysis, LO test, and Comparison.
Page 4 – Pair up, Wired/wireless connections, and Conclusion.