Item specifics
Description
This is a dual-channel Class-AB pure power amplifier board built around two independent STMicroelectronics TDA7293 ICs, one per channel. The TDA7293 uses a DMOS power stage in a MultiWatt15 package, rated at 100W per channel (8Ω, ±40V, THD=10%). The board accepts AC dual 12V–32V input, features an on-board 10A bridge rectifier and 2×4700μF/50V audio-grade filter capacitors, and drives 4–8Ω speakers. As a pure power stage, it contains no tone or volume controls and requires an external preamp or source. It suits bookshelf and floorstanding speakers in desktop Hi-Fi and living-room systems.
| Core Chip | TDA7293 (STMicroelectronics) |
| Chip Type | Class-AB DMOS Audio Power Amplifier |
| Channels | 2.0 Dual-Channel |
| Nominal Output Power | 2 × 100W |
| Chip Supply Voltage Range | ±12V ~ ±50V (DC) |
| Board Input Voltage | AC Dual 12V-32V (Dual 24V-32V recommended) |
| Output Impedance | 4-8 Ω |
| Frequency Response | 20Hz - 20KHz |
| Audio Input | 3P Terminal |
| Power Interface | 3P AC Terminal (toroidal transformer supported) |
| Output Interface | 10A High-Current Terminal |
| Filter Capacitors | 2 × 4700μF / 50V |
| Rectifier | 10A Full-Bridge |
| Protections | Short-Circuit, Thermal, Clip Detection, Mute/Standby |
| Heatsink | Aluminum-Magnesium Alloy Oversized Heatsink |
| Dimensions | 112 × 92 × 50 mm |
Typical Applications
Home Hi-Fi bookshelf and floorstanding speaker driving
AV amplifier power stages and home theater systems
KTV and stage active speakers
DIY desktop 2.0 audio and near-field monitoring
Mid-to-high-end active speaker upgrades and modifications
FAQ
Q: What size transformer is needed for the 2×100W rating?
A: A toroidal transformer with AC dual 24V-32V and at least 200W is recommended. 100W is the peak/maximum power of the TDA7293 at ±40V DC into 8Ω; actual continuous listening power depends on transformer capacity, thermal conditions, and load impedance. AC dual 24V rectifies and filters to approximately ±34V DC, already providing substantial output power; pushing toward AC dual 28V-32V yields more headroom but demands better cooling.
Q: Does the TDA7293 run hot? What thermal precautions are needed?
A: As a Class-AB DMOS amplifier, the TDA7293 dissipates significant heat at high power. This board includes an oversized aluminum-magnesium heatsink, but for 4Ω loads or extended high-volume operation, ensure the enclosure is well-ventilated. A fan may be added in sealed enclosures or high-ambient environments. The chip includes thermal shutdown, but frequent protection triggers indicate the thermal design needs improvement.
Q: Is this a pure power stage? Does it need a preamp?
A: Yes, this is a pure power amplifier board. The TDA7293 has a fixed internal gain of approximately 26dB and typically requires an external preamplifier (such as an NE5532 op-amp preamp or a DAC with volume control) for sufficient signal amplitude and volume adjustment. High-output sources (e.g., some professional DACs with 2Vrms output) can drive it directly, though volume control will be limited.
Q: Why is the power input AC rather than DC?
A: The board includes a 10A full-bridge rectifier and large filter capacitors, designed to accept the secondary output of an AC transformer (AC dual 12V-32V) directly. This allows users to complete step-down, rectification, and filtering with a single toroidal transformer, simplifying the power system. An isolated transformer must be used; never connect mains 220V directly.
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