TDA7294 2.1 TDA7293 2.1 power amplifier circuit

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Amplifier circuit tda7294 2.1 or tda7293 2.1, you can also use TDA7295 and TDA7296 or combine these cis. Uses single amplifier configuration for the satellites and bridged for the bass amplifier or subwoofer amplifier. Complete project including preamplifier with tone control, bass filter with frequency adjustment, power supply, 3 amplifier circuits, and protection circuit using UPC1237 IC and relay.

About 2.1 amplifier circuit using IC TDA7294 2.1 or TDA7293 2.1

Preamplifier circuit.
The signal input goes through p1 for overall volume adjustment, R11/C18 form a low-pass filter to avoid RF in our amplifier. The component values can be changed to suit your need.
IC1A and IC1B form the tone control circuit, with bass-mid and treble adjustment. P4 adjusts the volume of the satellite amplifiers.

Tda7294 2.1 Tda7293 2.1 Power Amplifier Circuit Pre-Amplifier

Dual operational amplifiers can be used equivalently, but prefer the original and better quality ones.

Subwoofer (Bass) filter circuit.
The signal of this circuit comes before the pre-tone, IC5A forms a buffer if you prefer you can change the resistor to increase or decrease the gain of the signal. Ic5B forms a high-pass filter with a cutoff frequency of about 43Hz and Ic7A low-pass filter with a cutoff frequency of 157Hz, i.e., a band pass from 43Hz to 157Hz. In Ic7B in P5 makes the cut-off frequency adjustment between 54 and 157Hz. P6 makes the volume adjustment of the bass channel. The signal from this stage goes to the subwoofer amplifier formed by IC8 and Ic9.

Tda7294 2.1 Tda7293 2.1 Power Amplifier Circuit Subwoofer Filter

Power amplifier circuit.
Uses the classic configuration for TDA78xx family, and can use TDA7294, TDA7293, TDA7295 or TDA7296. The mute and stand-by circuitry is shared between the 4 cis. The capacitor on the cis input sets the input impedance at 22K and together with the 1uF capacitor forms a high-pass circuit. The subwoofer amplifier is bridged and should be used with loads of 8 ohms or greater.

Tda7294 2.1 Tda7293 2.1 Power Amplifier Circuit

Symmetric power supply circuit.
The linear symmetrical power supply circuit uses a rectifier bridge and 6 capacitors from 4,700uF to 10,000uF. The transformer should be able to supply up to 10A per winding when it is 24V voltage. But it can be 12 + 12 to 25 +25V. If you prefer you can use a supply only for the preamplifier circuit.

Tda7294 2.1 Tda7293 2.1 Power Amplifier Circuit Symmetrical Power Supply

Protection Circuit
A protection circuit for the speakers and delay was adopted, using the UPC1237 IC and 2 relays. The power supply for the circuit comes from the transformer, being rectified by D2/D4. The resistor R35 was calculated to be used with a 24V relay.

Tda7294 2.1 Tda7293 2.1 Power Amplifier Circuit Upc1237

Table of CIS that can be used in our Amplifier 2.1.

CI TDA7293 TDA7294 TDA7295 TDA7296
maximum power 100W 80W 60W 50W
Maximum power of the subwoofer 180W 170W 100W 60W
Maximum voltage in 4 or 8 ohms satellites + 8 ohm subwoofer 22 + 22 VAC 22+ 22 VAC 18 + 18 VAC 12 + 12 VAC
Maximum voltage at 4 or 8 Ohms + 16 ohm subwoofer 25 + 25 VAC 25 + 25 VAC 22 + 22 VAC 18 +18 VAC

*Symmetrical source, mount 2.1.

Printed circuit board PCB suggestion for 2.1 amplifier assembly with tda7294 2.1 tda7293 2.1

Tda7294 2.1 Tda7293 2.1 Power Amplifier Pcb Component View
Tda7294 2.1 Tda7293 2.1 Power Amplifier Pcb Top
Tda7294 2.1 Tda7293 2.1 Power Amplifier Pcb Bottom
Tda7294 2.1 Tda7293 2.1 Power Amplifier Pcb Top Overlay

BOM for mounting or amplifier 2.1

Last Update: 05/30/2022 11:43 AM

Part Valor Descrição Quantidade
Resistors 1/4W
R1, R22, R23, R25, R28, R29, R31, R36, R38, R39, R41, R62, R63 10K Brown, Black, Orange, Gold 13
R2, R6, R8, R10, R51, R52, R54, R56, R57 22K Red, red, orange, gold 9
R3, R9, R53, R55 680 Blue, gray, brown, gold 4
R4 30K or 33K Orange, black, orange, gold 1
R5 20K or 22K Red, black, orange, gold 1
R7, R14 4,7 ohms 1W Yellow, violet, gold, gold 2
R11, R13, R27, R43, R50 1K Brown, black, red, gold 5
R18, R24, R26, R32, R34, R37, R40 100K Brown, black, yellow, gold 7
R12, R15, R16, R17, R20, R33, R42, R59 47K Yellow, violet, orange, gold 8
R19, R35 2K Red, black, red, gold 2
R21 15K Brown, green, orange, gold 1
R30 3.9K Orange, white, red, gold 1
R44, R46, R47, R49 6.8K Blue, gray, red, gold 4
R45 200K Red, black, yellow, gold 1
R48 68K Blue, gray, orange, gold 1
R58, R60 220 /2W Red, red, brown, gold 2
R65 220/3W Red, red, brown, gold 1
C1, C16 47µF/50v Electrolytic capacitor 2
C2, C17, C43, C52 1µF (105) Capacitor film 4
C3, C4, C5, C7, C9, C20 22µF/50v Electrolytic capacitor 6
C6, C8, C67, C68, C69, C70 4.700uF a 10.000µF/50V Electrolytic capacitor 6
C11, C12, C23, C24, C61, C62, C72, C84, C86 100nF (104) Ceramic Capacitor 4
C14, C15 100µF/50v Electrolytic capacitor 9
C18, C19 120p (121) Ceramic Capacitor 2
C21, C22, C30, C75, C76 10µ/50v Electrolytic capacitor 5
C10, C13, C32, C33, C41, C55, C56, C78 100n (104) Capacitor film 8
C25, C31, C36 47p (47) Ceramic Capacitor 3
C26, C37 2.2n (222) Capacitor film 2
C27, C28, C38, C39 47n (473) Capacitor film 4
C29, C40 10p (10) Ceramic Capacitor 2
C34, C35 220n (224) Capacitor film 2
C42 10n (103) Capacitor film 1
C57, C58, C59, C60 10n (103) Ceramic Capacitor 4
C44, C65, C66 100µ/50v Electrolytic capacitor 3
C64 4.7µ/50v Electrolytic capacitor 1
C83, C85 220µ/50V Electrolytic capacitor 2
C87 33µ/50V Electrolytic capacitor 1
D1 1N4448 Signal diode 1
D2, D3, D4 1N4004 or equivalent Silicon diode 3
IC1, IC4, IC5, IC7 NE5532 or equivalent Dual Operational amplifier 4
IC2 UPC1237 IC protector and delay 1
IC3, IC6, IC8, IC9 TDA7293 or TDA7294, or TDA7295, or TDA7296 Audio Amplifier IC 4
IC10 LM7815 15V positive voltage regulator IC 1
IC11 LM7915 Positive voltage regulator IC -15V 1
Led1 Led 3 mm Green Led 1
LED, LED2 Led 3 mm Red LED 2
B1 GBJ3510TB or equivalent 1000V 35A rectifier bridge 1
CN1 Connector JST-XH-03 2.54 mm 3 pin or equivalent Audio Input 1
OUT Connector KF8500 (Kf7.62) 3 pin Stereo audio output 1
POWER Connector KF8500 (Kf7.62) 3 pin Power transformer connection 1
SUBOUT Connector KF8500 (Kf7.62) 2 pin Subwoofer output 1
P1, P2, P3, P4 47K or 50K Dual potentiometer 4
P5, P6 47K or 50K Simple Potentiometer 2
K1, K2 G2R-2-DC24 or  SMI-24VDC-SL-2C Double relay 24V 5A 2
Solder, Wires, PCB, box, transformer.

Download the material list for this assembly, including the plate in Gerber, PDF, PNG, PS format, and datasheet of the components used.

Download the PCB files

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