This article will show you how to collect simple sound amplifier integrated circuit based STK4362 SANYO company. This UMZCH has the following options:
Maximum supply voltage - 50 V
Number of channels - 2
Power - 10W + 10W min, at THD = 1.0%
This amplifier is not suitable for a car due to a power supply other than 12 V, however, it will perfectly replace multimedia acoustics with a built-in amplifier.
Schematic diagram of STK4326 from the datasheet:
Integrated circuit STK4326, wiring diagram
Not finding ready-made on the Internet printed circuit board The decision was made to breed it on their own. The board was made in the SprintLayout program.
Integrated circuit STK4326, printed circuit board
After that, the printed circuit board was made by the method LUT(laser iron). A mixture was used for etching: hydrogen peroxide + citric acid + salt. The board in the photo is slightly different from the circuit made in SprintLayout, since after installation some places in the circuit were changed for ease of installation.
PCB for STK4362
Capacitors
C1, C2 - 470 pF (you can take ceramic or mica);
C3, C4, C5 - 47 microfarad 50 V (polar);
C6 - 1 microfarad 50 V (polar);
C7 - 100 microfarad 50 V (polar);
C8, C9 - 0.47 microfarad 50 V (polar);
C10, C11 - 220 microfarad 50 V (polar);
C12, C13 - 1000 microfarad 35 V (polar);
C14, C15 - 0.1 microfarad 50 V or more (film);
resistance
R1, R2 - 4.7 ohms;
R3, R4 - 120 Ohm;
R5, R6 - 1 kOhm;
R7 - 100 Ohm;
R8, R9, R10 - 100 kOhm;
Ready UMZCH on STK4326
For tinning the board and mounting parts, I used solder paste ordered from Aliexpress for 300 rubles. The tube in the photo is enough for more than one board, while this greatly speeds up the process, since it contains flux and solder at the same time.
At the beginning of the 90s, AIWA music centers were very popular. For a long time, the AIWA ZM-2900 music center served me faithfully. Over time, a laser disc player failed, then a two-cassette recorder and a radio receiver. The power amplifier and transformer remained intact.
The wiring diagram of the AIWA ZM-2900 music center can be downloaded from the attachment.
From the whole electrical circuit, I was interested in the STK419-150 stereo power amplifiers, which provided decent power (about 100 W per channel) and good sound quality.
The connection diagram of integrated amplifiers STK419-110, STK419-130, STK419-140 and STK419-150 is shown below.
Resistors R13 and R14 (with a power dissipation of at least 2 W) determine the level of current limiting through the output transistors of the integrated assembly. Inductances L1 and L2 are made by winding one layer of copper winding wire with a diameter of 0.8 - 0.9 mm on resistors R12 and R13 (MLT 2W). Resistors R16 and R17 with a power of 0.5 - 1W. The power of all other resistors is up to 0.25W.
The main characteristics of stereo amplifiers STK419-110, STK419-130, STK419-140 and STK419-150 are shown in the table.
| Integrated amplifier parameters: | STK419-110 | STK419-130 | STK419-140 | STK419-150 | ||
| Case | H3-20 | H3-20 | H3-20 | H3-20 | ||
| Output stage supply voltage (Vcc2) | min | V | ±25 | ±27 | ±30 | ±33 |
| max | V | ±37 | ±37 | ±42 | ±50 | |
| Supply voltage UN (Vcc1) | min | V | ±36 | ±37 | ±42 | ±50 |
| max | V | ±53 | ±57 | ±65 | ±70 | |
| Quiescent current (Io) | mA | 60 | 60 | 60 | 60 | |
| Maximum output power (Poutmax) | W | 2x50 | 2x60 | 2x80 | 2x100 | |
| Rated Load Impedance (Routnom) | Ω | 6 | 6 | 6 | 6 | |
| Frequency response (Bw) | kHz | 0,020-50 | 0,020-50 | 0,020-50 | 0,020-50 | |
| Input impedance (Rin) | kΩ | 55 | 55 | 55 | 55 | |
| Harmonic distortion at Poutmax | % | 0,2 | 0,2 | 0,2 | 0,2 | |
| Gain (Gv) | dB | 32 | 32 | 32 | 32 | |
| Manufacturer | Sanyo | Sanyo | Sanyo | Sanyo |
For the manufacture of the amplifier power supply, a W-shaped transformer of the music center was used, which has a primary winding of 220 volts, as well as a secondary winding with a common middle output (0V), with leads for powering the final stages (20V each) and a voltage amplifier (50V each). The power supply circuit is shown below.
Subjectively, the sound of the amplifier is more pleasant than on the LM3886.
I hope that this information regarding the STK419-110, STK419-130, STK419-140 and STK419-150 integrated circuits will be useful for making your own stereo amplifiers.
Best regards,
The stereo volume, balance and tone control on the ТСА5550 has the following parameters: Low harmonic distortion no more than 0.1% Supply voltage 10-16V (12V nominal) Current consumption 15 ... 30mA Input voltage 0.5V (gain at a supply voltage of 12V unit) Tone control range -14…+14dB Balance adjustment range 3dB Difference between channels 45dB Signal to noise ratio …
The schematic diagram of the transmitter is shown in Fig.1. The transmitter (27MHz) delivers about 0.5W of power. A wire 1 m long is used as an antenna. The transmitter consists of 3 stages - master oscillator (VT1), power amplifier (VT2) and manipulator (VT3). The frequency of the master oscillator is given by sq. resonator Q1 at a frequency of 27 MHz. The generator is loaded on the circuit ...
Amplifier parameters: Total range of reproducible frequencies 12 ... 20000Hz Maximum output power of MF-HF channels (Rн=2.7Ω, Up=14V) 2*12W Maximum output power of LF channel (Rн=4Ω, Up=14V) 24W RF channels with SOI 0.2% 2 * 8W Rated power of the low-frequency channel with SOI 0.2% 14W Maximum current consumption 8 A In this circuit, A1 is an RF-MF amplifier, and ...
The VHF receiver operates in the range of 64-108 MHz. The receiver circuit is based on 2 microcircuits: K174XA34 and VA5386, in addition there are 17 capacitors and only 2 resistors in the circuit. The oscillatory circuit is one, heterodyne. On A1, a superheterodyne VHF-FM was performed without ULF. The signal from the antenna is fed through C1 to the input of the IF chip A1 (output 12). The station is tuned in...
In recent years, radio amateurs are increasingly using power amplifiers on microcircuits. For many applications, it becomes impractical to assemble an amplifier on separate elements; in most cases, such amplifiers require the establishment of a protection device, setting the quiescent current of the output stage, etc. Integrated amplifiers are actually made according to the “soldered and ready” principle. Various versions of such amplifiers have already been repeatedly recommended on the pages of the magazine, however, the maximum (i.e., with nonlinear distortion of 10%) output power of amplifiers on a single chip is usually limited to 100 ... 120 W, at least when using chips from an affordable price category. Even when using two TDA7294 chips in bridging, the power in the load does not exceed 200 watts. But what if you need to assemble a more powerful amplifier, for example, for a disco? This describes a power amplifier on an integrated circuit that allows you to get output power up to 300 watts per channel.
The amplifier uses a hybrid chip STK4231-II manufactured by SANYO. This microcircuit is dual-channel, so only one microcircuit is required for the bridged switching option. When assembling an amplifier on such a microcircuit, a little more parts are required than for an amplifier on the TDA7294, however, it has a number of advantages and, most importantly, allows you to get a much more powerful amplifier. The microcircuit is much easier to mount on the heat sink, since its substrate is not connected to the heat-conducting surface of the case and it can be directly connected to the heat sink or amplifier case (for the TDA7294 microcircuit, the minus of the power source is connected to the substrate). This can often be critical, as isolating the heatsink from the chassis can sometimes be tricky.
Main technical parameters:
Rated output power, W…….250
Maximum output power, W… 320
Load resistance, Ohm ………5.3
Reproducible frequency range, kHz… 0.02…20
Harmonic coefficient, no more than, % …….0.4
Input voltage, mV ………………….500
Amplifier circuit
The amplifier is powered by an unstabilized source of bipolar voltage 2x (45 ... 55) V. The input signal to one of the amplifiers of the DA2 chip goes directly to pin 3, and to the second (pin 20) through an inverting buffer amplifier on the DA1 op-amp. The op amp is powered by +15 and -15 V voltage regulators, made on DA3, DA4 microcircuits. From the same stabilizers, if necessary, you can also power a preamplifier with tone controls or crossover filters. The gain of the power amplifier can be changed by selecting the feedback resistors R6 and R11. Their resistance in both arms of the amplifier should be the same.
Transistors VT1 - VT4 have a current protection unit that prevents the microcircuit from failing in the event of an overload. With an increase in current through one of the resistors R18, R28, the voltage drop across it increases, which leads to the opening of the transistor VT2 or VT1, respectively. This, in turn, leads to the operation of a thyristor analog on transistors VT3, VT4, and the microcircuit is blocked. To disable the blocking, you must turn off and turn on the amplifier again. If there is no need for a protection device, then you can not solder transistors VT1 - VT4 and related elements to the board - this will not affect the operation of the amplifier. Other variants of the protection device can be used with the amplifier, taking into account the property that when connected to the common wire of resistors R25, R31, the amplifier is blocked.
The microcircuit has a node that prevents clicks in the speakers when the power is turned on and off. To do this, pin 8 of the DA2 microcircuit receives a constant voltage supplied through the VD2 diode and the corrective circuits from the winding of the power transformer.
The amplifier has been tested in operation with a real load with a resistance of 5.3 ohms; the output power is somewhat less with a load resistance of 8 ohms.
Location of parts on the printed circuit board
In the design, you can use resistors C5-16 with a power of 5 W (R16-R18, R28-R30), MLT-1 (R22, R31, R38, R39), the rest - MLT-0.25 or MLT-0.5. Oxide capacitors - K50-35 or imported for a voltage of 63 V. The rest of the capacitors are film (K73 groups) or ceramic (except for the TKE H50 and H90 groups).
Op-amp DA1 can be replaced with K140UD7, KR140UD17, TL071, etc. KT502E transistors can be replaced with 2SA1207, KT814G, VT3 - with 2SC2911, KT815G, VT4 - with 2SA1209, KT814G. Inductors L1, L2 are wound with a wire with a diameter of 1 mm on resistors R17, R29 turn to turn in one layer along the length of the resistor.
The STK4231 microcircuit has two versions - with indexes II and V. The switching circuit for STK4231-V differs slightly from that recommended for the STK4231-II microcircuit, in which pins 1, 2, 21 and 22 are not used. For STK4231-V, additional elements are connected to them, as shown in fig. 3; all other conclusions are connected in the same way. The amplifier with STK4231-V has a lower harmonic coefficient - 0.08%.
Wiring diagram STK4231-V
Such an UMZCH can be powered both from a transformer mains power supply, and from a more modern pulsed one. The power of the power supply should be chosen 30 ... 40% more than the maximum power of the amplifier itself. An amendment to this article should also be taken into account: output 12 DD3.2 (see the diagram in Fig. 2 in the article) must be connected to output 3 DD3.1, and not as shown in the diagram. In addition, to limit the first inrush current when the UPS is turned on, it is useful to introduce a thermistor into the primary rectification circuit.
When using a switching power supply in the amplifier circuit, instead of the KD226A (VD2) diode, use KD212, and reduce the capacitance of the capacitor C14 to 1000 pF.
When assembling the described amplifier, special attention must be paid to fastening the microcircuits to the heat sink. The introduction of mica gaskets for insulation at such an amplifier power is unacceptable. Microcircuits allow heating up to 70 ° C during normal operation, but it is advisable not to exceed this temperature. It is advisable to use forced cooling by a fan. The heat sink can be installed pin (needle), in extreme cases, ribbed, acting as the rear or side walls of the amplifier case. It is possible to fix the microcircuit with screws using heat-conducting paste to a copper plate 3 ... 5 mm thick, and then a plate with the same paste to a dissipating heat sink. The dimensions of the plate should be 2 ... 4 times the dimensions of the microcircuit used. In this case, the efficiency of heat transfer will be maximum.
With proper assembly and the use of known-good parts, the described amplifier does not require adjustment. When powering the pre-amplifier from stabilizers DA3, DA4, it is only necessary to select resistors R38, R39 so that the voltage at the input of stabilizers DA3, DA4 is within 20 ... 30 V.
On a chip STK4048XI. We offer a slightly modified circuit of this amplifier based on STK microcircuits. With the circuit itself unchanged, and replacing only the microcircuits from the list below, you can change the output power of the audio frequency amplifier depending on your needs 6 to 200 watts. Depending on the marking microcircuits STK they have different levels of non-linear distortion: II - 0.2%; V - 0.08%; X - 0.008%; XI - 0.002%.
An approximate layout of radio elements on a printed circuit board:
At all microcircuits STK This series provide high output power and low THD. This allows you to get sound reproduction with high sound quality from the amplifier.
The supply voltage is bipolar from 20 to 95 volts (it varies depending on the brand of the microcircuit, see table). Amplifier load at least 4 ohms; optimal - 8 ohms. The input impedance of the UMZCH is 55 kOhm. Quiescent current is 120 mA. Output current up to 15 amperes (depending on the microcircuit used, see table). Chips of the STK40** series require the use of a radiator with an area of at least 400 mm 2 . For efficient heat dissipation, you can screw the chip onto the heat sink using heat-conducting paste.
The list of microcircuits in the table will be incomplete if we do not mention two more markings of this series, which provide an output power of the assembled amplifier of 200 watts. This STK4050II and STK4050V. The recommended voltage for the circuit on these microcircuits is at least 66 volts, and the maximum is 95 V.
Assembled amplifier on STK4050 with an output power of 200 watts:
