Nvarcher TDA7293 Parallel Power Audio Amplifier Circuit Board PCB

Origin:CN(Origin)
Maximum Power Per Channel:10W
Model Number:TDA7293
Package:Yes
Channels:2 (2.0)

This PCB
does not contain any components
, and the assembly drawings are for reference only.
Circuit introduction:
Since the parallel TDA7293 uses 4 ICs, if a side-mounted power supply is used (Figure 1 below), the distance between the ground wire of each IC and the power supply is different, and the farthest one is even more than 12CM, which will have a great impact on performance. , The layout is doomed to fail. Therefore, the side-mounted power supply is only suitable for the layout of 2 ICs.
The British lotus LINN LK140 pure rear stage adopts the power supply mid-mounted TDA7293 parallel amplifier layout (Figure 2 below).
This board adopts the same center-mounted power layout as Lotus LINN LK140, with symmetrical lines and short key laying distance. The result proves that the sound quality and stability are greatly improved compared with the side-mounted power supply.
The parallel TDA7293 has very few peripheral components, except for the standby mute components, only negative feedback and bootstrap capacitor components are relevant to the sound quality. The sound quality can be guaranteed as long as the IC is as close as possible. (The components above the screw hole that are close to the IC are all related to the sound quality, and the following are irrelevant to the sound quality.)
Only the power supply part can increase the investment, and the power supply decoupling capacitor must be as close as possible to the IC to get the best results. This board uses 2 pairs of 104 high-frequency decoupling (1 pair per channel), and 1 pair of 1000uf is responsible for low-frequency decoupling. The design is close to the IC's almost zero distance limit, which greatly improves circuit stability.
Package included:
1pcs PCB
board
Power requirements:
Main winding, AC dual 24-33V;
Secondary winding, double AC 18-24V (single 24V is also possible), (also can be shared with the main winding)
Transformer power is above 300W, the bigger the better
Even a single-chip TDA7293 can output a large current of 10A. If a 4 ohm speaker is driven in parallel, the current peak value exceeds 10A, so the speaker protection on this board uses a 10A large relay. While ensuring the sound quality, it provides speaker protection and delayed start-up (so the standby and mute of the circuit are no longer necessary).
Some suggest to install a DC servo circuit that uses an op amp. Here is a direct explanation: the advantages of a differential power amplifier have a high common-mode rejection ratio. Because the DC servo isolates the positive phase input resistance from grounding, it is equivalent to directly stifling the common mode rejection performance, and the gain is not worth the loss, so this board will not use the DC servo circuit.
The official circuit is 47uF, but Linn LK140 is 22uF. The tone will be a bit different. This board is officially marked as 47uF, but you can also install 22uF according to your preferences.
Parallel type is the unique design structure of TDA7293. TDA7294 95 96 cannot be used instead.
If the above-mentioned counterfeit products are used, the fireworks will burst.
Please use a multimeter to check whether it is genuine TDA7293
according to the following method: the digital multimeter is in the diode position, the red pen is connected to the heat sink, the black pen is connected to the 12-pin, and the readings about 0.7xx are all genuine. No reading reflects counterfeit products.