At present, Marshall’s three products cover three structural designs and different functional configurations, which meet the needs of different users and improve its layout in the TWS earbuds market. Among them, Marshall Minor III is a semi-in-ear earbuds, with a small and lightweight size, providing a comfortable wearing experience in the open ear canal.
01/ Marshall Minor III charging case teardown
Enter the teardown section below to see the internal structure configuration information.
Pry open the charging case cover and take out the internal cockpit structure.
The inner structure of the charging case cover.
The structure on one side of the cockpit, and the main board unit is fixed in the middle.
The structure on the other side of the cockpit is fixed with a wireless charging receiving coil.
The bottom structure of the cockpit, you can see the battery unit set inside.
Remove the screws and remove the motherboard and battery unit.
The small plate at the bottom of the cockpit that charges the earphones is fixed with screws.
The main component circuits inside the charging case, including the main board, the battery, the small board for charging earbuds, and the wireless charging receiving coil.
The information on the label of the built-in battery in the charging case, model: 682723, capacity: 410mAh/1.558Wh, nominal voltage: 3.8V, charging limit voltage: 4.35V, manufacturer: Chongqing VDL Electronics Co.,Ltd.
The silkscreen information on the inner cell is consistent with the outer label.
The front circuit of the battery protection board is equipped with Y1UD lithium battery protection IC and 8205A MOS tube, as well as thermistor and self-recovery fuse for detecting battery temperature.
The circuit on the back of the battery protection board, welding the positive and negative electrodes of the battery and the output wires.
The wireless charging receiving coil is set on the magnetic shielding sticker.
The small board circuit for charging earbuds, the wire connecting the main board is soldered on the small board.
Pogo Pin connector for charging earphones.
The circuit on the motherboard side.
The circuit on the other side of the motherboard.
The welding points of the battery and power input small board wires and the main board are glued and fixed.
A1semi ASM32F020 microcontroller, using C-Sky 32-bit CPU core, supports single-cycle multiplication and SWD debugging and a maximum operating frequency of 48MHz. Support 1.8 to 5.5V operating voltage range. Built-in 64K program flash memory, independent 2Kbytes data flash memory, and 4Kbytes SRAM.
Overvoltage and overcurrent protection IC for silkscreen 4A LD.
Silkscreen CFSR5 V004L F0021 wireless charging receiver IC.
TPS SY8825 bluetooth headset charging bin SoC, which integrates charging module and discharging module. The charging current can be adjusted externally. The discharge module integrates two output current limit switches, provides independent load presence detection and load insertion detection, and supports output current detection. The package form of SY8825 is ESSOP10.
TPS SY8825 supports discharge enable control, and MCU can flexibly control the discharge function of the chip directly through EN. SY8825 integrates a single-line status code output, which is convenient for the chip to report the chip status to the MCU. SY8825 is very suitable for the design of bluetooth headset charging box, which greatly simplifies peripheral circuits and components, and provides an easy-to-use solution for the application of bluetooth headset charging box.
According to 52audio, the TPS power management chip has been adopted by Edifier, Baseus, Xiaomi, OPPO, OnePlus, realme, 1MORE, Baidu, JBL, HARMAN, Lenovo and other brands.
Power management chip peripheral 2R2 power inductor.
Bluetooth pairing function button.
Type-C charging socket.
LED indicators on the motherboard.
The hall element of the silk-screen Hy1cB is used to sense the magnetic field change when the charging case cover is switched on and off, and then notify the charging case MCU and the earbuds to pair or disconnect from the connected device.
02/ Marshall Minor III earbuds teardown
Go to the earbuds teardown section. Pry open the headphone cavity along the parting line.
The internal structure of the front cavity, the battery unit is fixed on the back of the speaker, and is wrapped with black tape.
The internal component cables of the front cavity are connected to the main board of the rear cavity through the BTB connector.
Pick apart the BTB connector to separate the cavity.
Take out the internal structure of the front cavity of the battery, and weld the battery and speaker wires to the cable respectively. One end of the cable is provided with a charging contact and an optical sensor, and is fixed on the cavity wall.
Take out the speaker, the internal structure of the cavity.
There are three tuning holes around the back of the speaker unit to improve low-frequency performance.
The front diaphragm of the speaker unit.
After actual measurement, the size of the speaker is about 12mm, which is consistent with the official promotion.
The earbud has a built-in soft-pack button test battery, model: 211204, voltage: 3.7V, capacity: 35mAh/0.13Wh, also from VDL.
The screen-printed QR code on the back of the battery is used for product traceability.
The wiring circuit.
Optical in-ear sensor, used to automatically pause music playback when removing earbuds, and automatically resume music playback when wearing it.
Two metal copper post connectors for charging earbuds.
The flat cable is connected to the BTB connector male socket of the motherboard.
The bottom structure of the rear cavity, the main board is glued and fixed.
Remove the bottom end plug and pull out the motherboard unit.
Touch detection patch at the bottom of the back cavity.
The circuit on one side of the earbud motherboard is provided with a plastic cover, and a bluetooth antenna is attached to the cover.
The circuit on the other side of the motherboard.
Remove the antenna cover fixed by the positioning post.
The inner structure of the cover plate, the exposed copper of the bluetooth antenna is connected to the motherboard.
There is a laser engraving MC45 D129 MEMS microphone on the cable at the end of the motherboard, which is used for voice call pickup, from MEMSensing.
Pogo Pin connector for connecting the bluetooth antenna.
Metal dome used to connect the touch detection patch.
Female BTB connector for connecting cables inside the front chamber.
Qualcomm QCC3046 bluetooth Audio SoC. The QCC304x series combines enhanced features such as stability, good sound quality, scalability, low latency and low bit rate audio transmission. Supports Bluetooth 5.2 and Qualcomm aptX Adaptive codec. Supporting Qualcomm TrueWireless Mirroring technology, the left and right earbuds can be quickly switched in multiple usage scenarios.
In addition, Qualcomm QCC304x series bluetooth audio SoC also integrates hybrid active noise cancelling technology. Support cVc call noise cancelling technology, which can wake up the phone’s voice assistant through touch or button.
According to 52audio, there are many TWS true wireless earphones, head-mounted, neck-mounted bluetooth headphones, smart speakers, smart audio glasses and other audio products that use Qualcomm bluetooth audio SoC.
A 32MHZ crystal oscillator that provides the clock for the bluetooth chip. Silkscreen 5AJI memory IC for storing bluetooth pairing information.
Touch detection IC for silkscreen 133A1h.
Silkscreen 1hA3 lithium battery protection IC.
Silkscreen W7CKH IC.
All components of Marshall Minor III true wireless earphones.
03/ Summary
Marshall Minor III continues the Marshall family-style black gold design style in terms of exterior design, which is highly recognizable by the brand. The charging case adopts a vertical rounded square design, and the imitation leather texture of the lychee leather pattern. The earbuds adopts a semi-in-ear design, the headset stem is designed with a diamond lattice and a gold tail plug, and the “M” brand LOGO enhances the product texture and recognition.
In terms of internal configuration, the charging case supports both wired and wireless input power, and the built-in battery capacity is 410mAh, which comes from VDL. On the main board, the TPS SY8825 bluetooth headset charging compartment SoC is used, and the charging module and the discharging module are integrated inside. The charging current can be adjusted externally, and the discharge module integrates two output current limiting switches to support output current detection. A1semi ASM32F020 microcontroller, used for charging case control.
In terms of internal configuration of earbuds, it adopts 12mm custom drive unit, VDL 35mAh soft pack button battery, MEMSensing MEMS microphone, and optical in-ear detection sensor. The main control chip is Qualcomm QCC3046 bluetooth audio SoC, which supports Bluetooth 5.2, aptX Adaptive codec, TrueWireless Mirroring connection technology, cVc call noise cancelling technology, and provides support for various functions of earphones.
Source: 52audio
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1 Comment
Thank you – your teardown made me realise it was “only” the microphone that came apart and I don’t need to send them back , because calling isn’t the important part for me.