TDA7294 is a class AB monolithic audio amplifier integrated circuit launched by SGS-THOMSON Microelectronics in the 1990s. It swept away the raw, cold and hard sound of previous linear integrated amplifiers and thick film integrated amplifiers, and is widely used in HiFi fields, such as home theaters, active speakers, high-performance TVs and other fields.
The chip adopts a 15-pin dual-row asymmetric plug-in package, the differential input stage is composed of bipolar transistors, and the driver stage and power output stage use DMOS field-effect transistor semiconductor technology. This hybrid semiconductor manufacturing process allows TDA7294 to take into account the advantages of bipolar signal processing circuits and MOS power tubes, and the playback sound is very friendly (it is praised by audiophiles as a “tube-flavored amplifier”); the built-in silent standby function, short-circuit current and overheating protection functions make its performance more perfect. It can be used in HiFi home audio, active audio, high-performance TVs and other fields.
Tda7294 amplifier board
tda7294 amplifier board PCBA
- This circuit is an official standard circuit, stable and reliable.
- The filter uses a large electrolytic capacitor with a withstand voltage of 50V and a capacity of 2200uf.
- Power supply voltage: dual 12-36V ring transformer, dual 32V ring transformer is recommended
- Output power: 85W*1 undistorted rated power, peak power 100W
- Can easily drive speakers above 100W, speaker impedance: 4-8 ohms
- PCB size: 50*50mm
Basic parameters:
Power supply: dual 18-28V AC
Power: 2X80W+160W subwoofer
Circuit board size: 218x98MM
Potentiometer function: low frequency frequency adjustment, subwoofer volume. Left and right channel volume, treble, bass.
Adopting the new laser dark word TDA7294
The power filter uses 6 63V3300UF capacitors, and the rectifier uses a 25A imported rectifier flat bridge.
PCB uses 1.6mm thick double-sided board, 2.0 ounces copper thickness, and full tin spraying process to ensure good passing performance of large and small currents.
Fever component assembly, the subwoofer part consists of two new TDA7294 BTL output,
The low-pass filter is designed according to the frequency adjustable design of home theater style (50-150HZ), with strong power!
The left and right channels are served by two TDA7294 respectively, and the input coupling capacitor uses the German imported WIMA 2.2UF coupling capacitor, which makes the sound sweeter!
The signal-to-noise ratio of the board is also very high, and even if you put your ear close to the speaker, you can’t hear the AC noise! It is the best choice for upgrading 2.1 amplifiers!
TDA7294 datasheet
TDA7294 Main Features
Wide supply voltage range: ±10V ~±40V
High output power: 70W (up to 100W)
Standby and mute functions
Noiseless ON/OFF switch
Low noise and low distortion
Short circuit protection and overheat protection
TDA7294
Pin function
Pin 1 is the standby terminal;
Pin 2 is the inverting input terminal;
Pin 3 is the positive input terminal;
Pin 4 is grounded;
Pins 5, 11, and 12 are empty pins;
Pin 6 is the bootstrap terminal;
Pin 7 is +Vs (signal processing part);
Pin 8 is -Vs (signal processing part);
Pin 9 is the standby pin;
Pin 10 is the mute pin;
Pin 13 is +Vs (final stage);
Pin 14 is the output terminal;
Pin 15 is -Vs (final stage)
DIY Production
1) The first step is to get the PCB. Here you can make the PCB yourself by DIY ironing method. Since the PCB is easy to make, the PCB design is kept single layer only, or you can get ready-made quality PCB from best.or custom tda7294 amplifier board.
2) After the PCB is completed, carefully mount all small components like jumpers, resistors, diodes, etc. to the PCB and trim their terminals, then solder them to the PCB first, because there are many components on this board, so it is better to solder them one by one
3) After installing the small components, install the large components like capacitors, fuse holders, rectifiers to the PCB and solder them. (Don’t install the power filter capacitor, 22000uF capacitor for now. Completed in the following steps)
4) After that, it’s time to mount all 7 ICs to the PCB and solder them.
5) Now properly mount the heat sink on the IC using insulating MICA and insulating plastic shoulder washers. Remember to use good quality thermal paste between the heat sink and IC.
6) After mounting the IC on the heat sink. Check the continuity between the heat sink and the IC back plate using a multimeter. There should not be any continuity between them. Please note the heat sink isolation
7) Now mount the cooling fan to the PCB using cable ties or any other suitable method.
The board assembly is now complete. Clean the track side of the board using IPA (Isopropyl Alcohol) or cleaning flux and then power the board using a 20-0-20 VAC transformer or a 24-0-24 VAC transformer.
Which one has better sound quality, TDA7294 or LM3886? Voltage AC 28v
LM3886 has better bass because its maximum current can reach 10A, which means it can drive a 2-ohm box without any problems. From the parameters alone, LM3886 is worse than 7294. And it is true in practice, especially for bass. If the transformer is OK, it feels very powerful. 7294 is not as good as 3886 in bass. The current is large when it comes to bass. 7294 itself has overcurrent protection. When the current reaches a certain level, it starts to limit the output current. However, 7294 is better in treble.
