The post explains how to build a simple yet powerful 32 watt amplifier circuit using a single chip TDA2050 and with a handful of resistors and capacitors.
By: Dhrubajyoti Biswas
Working Principle of TDA2050V
This article will detail building a stereo amplifier along with an output for a headphone jack. It is built by using the IC TDA2050V integrated circuit. According to the data sheet that comes along with the IC, TDA2050V is ideal for Class-AB based audio hi-fi amplifier.
The required operating supply voltage for TDA2050V should be in the range of +/-4.5V to +/-25V.
Using 25 watts of power you can achieve at least 65% efficiency. However, it is important to note that to maintain stability on the system the circuit gain should be managed with a gain of around 24dB.
We built the amplifier with an intent to use it with RB-51 bookshelf speakers. They are 8 ohms possessing a sensitivity of 92dB @ 2.83V / 1m.
Since this amplifier utilizes less power, therefore using TDA2050V is quite a right choice.
Moreover, the amplifier will also work with other audio devices, such as, tuner, mp3 player etc. It may be interesting to note that, the smaller TDA2050V chip produces a better quality sound than the bigger version.
Constructing the Amplifier
The above diagram is of an application that uses split-supply. The diagram is taken from the datasheet for ease of understanding. Also it is advisable to read the datasheet that comes along with TDA2050V chip. This will help to understand setting up the stereo in different ways.
The datasheet specified for the IC also details a recommended PCB design, which we have used as a reference for this experiment. The figure above, taken from the datasheet shows the basic PCB layout:
The amplifier that we have built in this experiment, its schematic design is presented below
Schematic of hi-fi amplifier using TDA2050
To build the circuit, here we have followed the PCB design as shown in the above figure. Also, the circuit could be simply assembled on a perfboard.
In order to block DC current flow, we used a capacitor of 1uF MKT type. However, there is no such restriction and you are free to go for any other relevant capacitor as per your choice.
Constructing a circuit is not at complex. However, there are certain vital factors that should be kept in mind during design, as stated below:
- Grounding or earthing is very important to maintain low noise and an hum-free response from the system. This is why star grounding process is probably the best suited in this case. The system employs two ground points, use one for signal and the other for power, further connecting both of them via singular connection.
- For each channel use individual power supply.
- Keep signal wiring short and ensure the wires are twisted tightly. Maintain a distance with the AC power sources. Also it would be better if you can keep the wiring close to the chassis.
Power Supply
In this amplifier design the power supply adheres to the standard power supply regulations and employs snubbers for better safety.
Besides, we used torroidal transformer of 120VA and 18 Volt dual secondaries. Also we used 35A rectifier bridges, however, you can also use 15A – 25A bridge.
As per the design of specs, it uses MUR860 ultra-fast recovery diodes. You can also try other discreet diodes that are ultra-fast, but as per this experiment we figured out that it can be ignored and normal rectifier diodes can be used.
You can find 10,000uF capacitor for each power supply. The hum suppressed by the supply is quite inaudible albeit we could hear some on a microphone, when it has max volume and has no signal connection.
TDA2050 Power Supply Design
Cabinet
For the enclosure, here we used Hammond’s chassis [Model ID: 1441-24]– 12” x 8” x 3”, steel built and satin black in color.
The circuit board and transformer was carefully placed above just on the top of the enclosure. The volume control, headphone input and power button was placed at the front for ease of use.
We used gold-plated RCA standard jackets for the input. For output we used standard output plugs of three-way binding posts, which accepts bare wire, 4mm banana plugs or spade connector. However, please note that the binding posts of the speaker and the input jackets have their insulation from the chassis made by nylon spacers.
Heat Sink
As a standard procedure we have placed the heat-sink on the rear of the chassis, which is measured 50mm x 88mm with 35mm fins @ 2.9 C/W. Also we need to make a hole on the chassis so as to mount TDA2050 directly. As a note, please ensure TDA2050 is kept separate from the chassis because of the potential issue on TO-220 package. If this is not taken care of, then there is high chance of the chip to get destroyed once the system receives power.
In regard to isolation, you can use mica or silicon pads. Also please keep in mind to add a spacer for mountain crew to save the chip. Upon setting up the system, do finally check all the components and their placements. For instance, ensure a check to avoid continuity between heat-sink / ground / chassis and the chip.
As a conclusion, do maintain good thermal contact. Here we used thermal grease before mounting the system.
SHARRAN VISHAAL K says
Kindly let me know if I can use the center transformer in this link mentioned below for TDA2050
Split supply circuit:
——
PLease let me know ASAP
Swag says
no it will not work, you must have two separate wires for the center tap, meaning the two winding should be separate and isolated. moreover the current should be preferably 5 amps
SHARRAN VISHAAL K says
Extremely thanks for the prompt reply sir
Swag says
You are welcome!
Subhabrata Das says
Thank you for the reply Sir. Btw TDA 2030,2040,2003,2050 and LM 3875,3876 are now obsolete and Texas Instruments doesnt manufacture them any more. So can provide the circuit with any alternative if possible?
Swagatam says
Hi Subhabtrata, in that case I think you should try the following mosfet based design, I have tested it, the output quality is superb, and you can also easily upgrade it upto 200 watts simply by increasing the supply input
https://homemade-circuits.com/2012/04/how-to-make-simplest-100-watt-mosfet.html
Subhabrata Das says
Sir I have a 15-0-15 volt tranformer… But here the vltages are higher.. Is there no other alternative for using any new class AB amp ic other than transistor(circuit is a bit complex)? and what should be the circuit for low pass filter? I want the cutoff to be around 100hz
Swagatam says
Subhabtrata, using transistors looks easier because you can get the parts easily in the market and is fully customizable….whereas an IC can easily get obsolete or be difficult to find. also this design can be upgraded much higher levels just by increasing the supply voltage.
moreover the link which I referred involves only a handful of parts, and can eb easily assembled on a piece of veroboard, and no prior adjustments.
for a low pass filter you can refer to the following links:
https://homemade-circuits.com/2016/01/design-low-pass-filter-circuit-quickly.html
https://homemade-circuits.com/2012/02/how-to-make-simple-active-low-pass.html
Swagatam says
Subhabrata, you ca refer to the following diagram, this is perfectly correct
https://1.bp.blogspot.com/-HQcHK8mj9Ek/WWtqnxc3pCI/AAAAAAAAQ2U/FxXSxFbIj5ol1WEtLN_z6vF_27LGw1ZKgCLcBGAs/s1600/TDA2030_200watts_amplifier_4A85Z.gif
But I am not sure whether the IC can be replaced with TDA2050 or not…you can refer and compare the two datasheets, if you find their pinout specs matching exactly then perhaps you can give it a try
Subhabrata Das says
Thank you Sir, and One last question. I have stereo inputs and the output is mono so how to mix the stereo inputs?(incase of 2030/2050). I want one mono output not stereo.
Swagatam says
If the stereo outputs already have a series capacitor on each channel, in that case you can directly join them together with the amp input, otherwise put a 10uF capacitor with each L/R channel outputs and connect the ends together with the amp input.
Subhabrata Das says
Sir I want to power a 60watt 8ohm subwoofer. Can u please modify the circuit with dual tda2050 in bridge mode?? Also please tell me the transformer specification that I need to buy. Will Ne5532 increase the gain?
Swagatam says
Hi Subhabrata, you can find the details in the following link
http://www.diyaudio.com/forums/chip-amps/195315-bridged-tda2050-single-supply.html
Swagatam says
If possible I will try to update it soon in website also…
Rahul says
Sir,
I want to used this in a car , so could you suggest the power supply in car using single battery how can I obtain +12 0-12 voltage .
Swagatam says
Rahul, you can try the following concept
http://www.learningelectronics.net/circuits/images/dual-raildc%20powersupply.gif
sid says
thanks sir for reply,i have used 100k pot for input & now i will replace filter cap from 4700uf to 6500uf or 10,000uf as u said.One more question sir ,can 2 tda2050 work on12-0-12 5a current because when i switch on the amp cracking sound continue coming from speaker & heatsink heating more .should i decrease the current of transformer & use 12 volt center tapped 3A current transformer? How much current need to drive 2 tda2050 stereo circuit at full volume? plz help me sir
Swagatam says
I think the problem is not in your power supply
If your IC is getting hot even at 12V then your IC could be faulty or not an original version.
reduce the volume and check again, if still distortion persists then surely the IC has problems assuming you have done rest of the things perfectly.
sid says
i have made this stereo tda2050 amplifier split supply circuit according to datasheet on 12-0-12 5amp but music is low and lots of noise is coming from speaker .speaker is of 8 ohms & input source is mp3 player also i have made star ground. plz sir help me i dont have much knowlege about electronic i have spend lots of money & time in making this amp
Swagatam says
are you using a volume control at the input? you should use one and adjust it for adjusting the input level correctly.
make sure the filter capacitors are large enough, above 6500uF/50V or even 10,000uF