Despite the abundance of powerful microcircuit and transistor audio amplifiers, there is always a need to have a small portable stereo amplifier that does not require powerful power. Just this one can be built on the TDA1517P chip, its other name is YD1517P. The index “P” at the end means that the microcircuit has a DIP 8 package. This microcircuit is also available in a SIL9MPF package, which provides for the installation of a radiator, in which case it is called TDA1517.
On AliExpress such a microcircuit costs a penny - TDA1517P.
Scheme
The TDA1517P connection diagram is extremely simple and contains only the minimum necessary wiring. Capacitors C1 and C2 are pass-through; the larger their capacity, the more low frequencies there will be at the output of the amplifier. Capacitors C4, C5 are also pass-through capacitors, they serve to cut off the DC component of the signal; their capacitance can vary between 470-1000 µF. C6, C7 – power supply filter capacitors. All electrolytic capacitors should be rated at a minimum voltage of 25 volts.The optimal supply voltage for the circuit is 9-12 volts, the output power is 5 watts per channel, which is enough to sound a small room. R1 – volume control potentiometer, you can use any dual 50 kOhm or 100 kOhm potentiometer with a linear or logarithmic characteristic.
S1 – mono/stereo mode switch, needed in cases where the input of the circuit receives a signal from only one channel, for example, from old cassette players or radios. When S1 is closed, the signal “splits” and both speakers play, even if a mono signal is received at the input.
You can download the board and schematic here:
Amplifier assembly
As always, assembly begins with the manufacture of a printed circuit board, a drawing of which is attached to the article. The board is made using the LUT method, the design is ready for printing and there is no need to mirror it.
After the board is etched and tinned, we solder the parts onto it - first of all, resistors, a diode, a microcircuit, then massive capacitors. Lastly, we solder the controls on the wires to the board - toggle switches, a variable volume resistor, a terminal block for connecting speakers, a sound input jack, Light-emitting diode, power socket. I also installed an additional jack 6.3 connector, which is connected in parallel to the main jack 3.5. The plus from the power connector goes first to the on/off switch, and only then to the board. The second toggle switch is a mono/stereo switch. When soldering is completed, remove any remaining flux from the board and check for breaks or short circuits in the tracks.
Installation in the case
The board can be placed in any suitable size case.If the case is metal, then you should connect it to the minus of the circuit; protection from external interference will appear. I chose a small plastic case with dimensions 100 x 70 x 35 mm.
When drilling holes, you should take into account the dimensions of the components that are located inside, as well as the diameter of the holes for installing parts. All parts, especially the audio input jack and the volume potentiometer, should be connected with the shortest possible wires, otherwise hum may occur. The board can be secured to the case using stands with screws or glue.
First use and listening
After the amplifier is assembled, you can begin testing. We connect the 9-12 volt power supply by connecting an ammeter in series with it. Turn on the amplifier with the toggle switch, the ammeter should show a quiescent current of 40-80 mA, Light-emitting diode will light up. Now you can connect a signal source, for example, a player, computer, telephone, speakers to the terminal block and turn on music. During operation, especially at high volume, the body of the TDA1517P microcircuit can heat up to 40-50 degrees, this is normal. To power the amplifier, you can use any 9-12 volt household power supply with a current of at least 500 mA. Happy assembly.
