However, in the foregoing, there are various suggestions regarding enhancing its output power. If built into a bridge configuration and driving an 8 ohm speaker, the peak power for such a configuration is 5 x 5 x 8 i. Such a configuration works well in practice, both with split rail power supplies and with single rail power supplies. My experience with many many TDA that I have used, is to limit the total supply rail to 45 volts maximum providing a few volts safety margin.
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One thing to note is that the gain of the circuit needs to be at least 24dB to maintain stability. The amplifier was built to drive a pair of my friends Klipsch RB Bookshelf speakers.
The speakers are 8 ohms and have a sensitivity of 92dB 2. The amplifier can be driven by most line-level sources such as an mp3 player, cd player, tuner and so on. Figure 1 below is from the data sheet and shows the typical application using a split supply. I used a protoboard for my amplifier details below.
Only one channel is shown. A double pole, double throw DPDT switch is shared between both channels and this allows switching the output between speakers output or headphone output. If you do not need a headphone output, you can eliminate the DPDT switch and the resistors after the switch. The gain of the circuit is 33 30 dB which should work well for most line level sources. Use your personal preference of capacitor here. Most film type capacitors polypropylene, polyester, mylar Here are some additional construction tips that I hope you find useful.
A proper grounding scheme is important to obtain low noise. The best approach is to use a star grounding technique. You will want two star ground points - one for the signal and one for the power. The two ground points should then be connected together through a single connection. Try keep the signal wiring as short as possible. Also, the signal wires should be tightly twisted together.
You will also want to keep them away from any AC sources like the mains power cord and the transformer. Keeping the wires as close as possible to the chassis also helps. Use separate power supply wiring to each channel. This project requires a mains wiring connection or V which you do not want to get in between. Faulty or incorrect mains wiring can result in death or serious injury!
Please refer to your local electrical code for the mains connection requirements. Use appropriate fuses and connect the chassis to the mains "earth". A torroidal transformer with dual 18 Volt secondaries and rated at VA 3. For the rectifiers I used 35A rectifier bridges A bridges should also work.
Discrete ultra-fast rectifiers can also be used at an increased cost. I found no need to use them. Each power supply rail has a 10,uF capacitor which is shared between the channels. The supply has only very slight hum which can only be heard with my AKG headphones when I turn the volume to max and no signal connected. The transformer and circuit boards are hung from the top of the enclosure.
The power switch, volume control and headphone socket are on the front of the enclosure for easy access. The speaker output plugs are standard three-way binding posts that will accept a 4 mm banana plug, a spade connector or bare wire. Note that the input jacks and speaker binding posts are insulated from the chassis using the supplied nylon spacers.
The heat sinks are placed on the back of the chassis. For the heat sinks I used a pair that each measured 50 mm x 88 mm with 35 mm fins and rated at 2. Additional details to determine an appropriate size of heat sink are described in the data sheet. A hole was cut in the chassis so that the TDA package could be mounted directly on the heat sink. Note that the TDA IC must be isolated from ground the chassis as the negative potential resides on the metal tab of the TO package.
Failing to do so will destroy the chip once power is applied. Also, to ensure good thermal contact I used some thermal grease on the back of the chip prior to mounting. To my ears the small TDA chip produces a very good sound which can hold it own against various high quality amplifiers I have used. The amp has the ability to produce deep bass, clear mids with a wide sound stage and crisp highs that are not too sharp.
Have fun building this one! If you do build one, I would be happy to see some photos of your TDA amps. Most importantly, have a lot of fun by listening to your work. I have made a PCB design for the amplifier circuit. The PCB layout must be mirorred to expose the copper.
Flip the exposure film to the left. Direct Toner: The text must be readable. Also below is an updated list of components for the new PCB.
DIY TDA2050 IC Hi-Fi Chip Amplifier