Design solutions that pursue the sound quality and experience you need
The board runs on a 24V DC bus. A MVSILICON DSP handles multi-channel signal routing (Bluetooth/AUX inputs, three power outputs) — switching, dynamic crossover, and volume balancing — in the front end, while efficient Class-D amplifiers drive the outputs in the back end. Two 50W channels drive full-range or satellite speakers, and a dedicated 100W channel feeds the subwoofer. At the 4Ω rated load, overall efficiency stays above 85% with passive cooling — no extra fan required for long sessions.
Desktop active speakers can drop the external amplifier entirely. Car and RV audio draw straight from the 24V bus, while retail broadcast and meeting-room reinforcement need stable drive into 4Ω passive speakers. Bluetooth streams from a phone; AUX takes a mixer or TV feed, and the two sources switch with one tap across home, travel, and commercial use.
The subwoofer channel is tuned for a 4Ω woofer. The DSP applies an 80–120Hz low-pass with adjustable slope plus a limiter to prevent clipping on big transients. The 100W rating gives solid room-filling extension without blowing the driver on overload peaks — a good balance of punch and lifespan for KTV, AV, and background music.
Bluetooth 5.x receives phone or tablet audio; AUX serves wired gear. Priority is customer-configurable: inserting AUX auto-mutes Bluetooth and removing it restores it, avoiding dual-source crosstalk with no pop on switch. Standby draw stays below 1W, meeting efficiency and thermal limits for always-on use.
The board integrates over-temperature, over-current, short-circuit, and DC protection that throttles or mutes on abnormal load. The DSP side adds soft-start and clipping protection to avoid turn-on thumps and bass distortion. The unit passes 24V wide-voltage, full-load thermal, and 72-hour aging tests, giving consistent mass-production quality and a low return rate.
An I2C/SPI tuning interface and status LED let customers write their own EQ and crossover parameters. The Bluetooth module is packaged separately, and AUX comes as gold-plated RCA or 3.5mm. Liwei Electronics supplies schematics, BOM, and a full-board test fixture to shorten the path from prototype to production.
Q: How do I power dual 50W plus 100W at 4Ω?
A: The whole board shares a 24V DC bus and the Class-D stages draw on demand. Size the supply for at least 200W headroom and place filter capacitors close to the stage to avoid voltage sag on transients.
Q: Can Bluetooth and AUX play at the same time?
A: No. The design is single-source: inserting AUX mutes Bluetooth, eliminating dual-source crosstalk, and the switch is pop-free for safer daily use.
Q: Can the crossover point be customized?
A: Yes. The MVSILICON DSP crossover point, slope, and EQ are all rewritable via the reserved interface. Liwei Electronics provides default parameters and tuning support to match your speaker acoustics.
Shenzhen Liwei Electronics Co., Ltd. has 12 years of experience in audio amplifier and headset solution design, serving 15+ well-known brands and 300+ clients. This 24V amplifier PCBA supports rapid prototyping and custom tuning. Request a quote to get the datasheet and samples.
Keywords: 24V amplifier PCBA, 4 ohm speaker, dual 50W, Bluetooth AUX, MVSILICON DSP
