Amplifier on a chip STK4048II This is a cheaper analogue of the chip from SANYO - STK4048V.
STK4048II is a microcircuit on which even a novice radio amateur can assemble a professional high-quality amplifier that is not inferior to high-quality industrial transistor amplifiers.
Once, an amplifier with a power of about 100 W was required to “drive” a loudspeaker with a resistance of 8 ohms. After studying the reference books, the choice fell on the microcircuit STK4048II. I am a curious radio amateur and don’t like to repeat myself, but here is a new series of microcircuits for me. STK is criticized for its lack of protection, and praised for its “good sound.” The reference data turned out to be quite scanty, and there are errors in the diagrams. To “not be excruciatingly painful” for a burnt-out microcircuit and wasted money, I advise you to use my recommendations.
The Roman numeral “II” in the designation reflects the harmonic coefficient, in this case - 0.4%. Microcircuits with the number “XI” have a harmonic coefficient of 0.007% in the frequency band 20 Hz...50 kHz. Output power at a load of 8 ohms is 120 W. I haven’t tested the microcircuit at a 4 Ohm load, but, according to reviews on the Internet, it turns out to be 60 W, and it gets very hot. The IC power supply is bipolar, from ±55 to ±75 V. If you look at the structure of the microcircuit (Fig. 1), then, taking into account the external “piping” of parts, we will see a classic UMZCH 80-90s.
Fig.1 Structure STK chips 4048II
Now about the typical errors in using STK:
1. The gain of the original circuit is 100. This is a lot, and there is a possibility of self-excitation. This is what happened to me, but I was ready for this and reduced the resistance of R7 from 68 kOhm to 20 kOhm (Fig. 2). The amplifier immediately stopped energizing. Some radio amateurs recommend reducing the resistance of R7 to 13 kOhm.
Rice. 2
2. The original circuit uses 5-watt wirewound resistors R10...R13 with a resistance of 0.22 Ohms. Such resistors have high inductance, and the consequences of this for the “sound” are unpredictable. Moreover, the power of these resistors is clearly overestimated. 2-watt metal film ones are quite suitable here.
As my experience shows, the fewer inductances in the audio path, the better sound! The only exception is the LR filter L1-R14 at the amplifier output, which is necessary to compensate for load reactivity. Coil L1 is wound on a mandrel Ф10 mm and contains 18 turns in one layer. Wire diameter - 0.8 mm. There is a resistor R14 inside the coil. All capacitors in the UMZCH circuit and in the power supply are with an operating voltage of 100 V.
The amplifier is additionally equipped with a protection circuit against DC voltage amplifier output and connection delay speaker system(Fig.Z).
Sound amplifier 200 watt- I suggest for repetition the amplifier circuit with excellent quality sound, minimal noise level. The device is made using the integrated, hybrid properties of the STK4050 microcircuit from the Japanese company Sanyo. To have good quality sound and its highest gain, the amplifier needs a power supply that matches the power of this circuit. And also a rectifier with a sufficient total capacitance of capacitors that create necessary conditions For efficient work loads.
This amplifier model is perfect for working as part of home theater or personal computer, as well as in a set of other audio systems. For example, such a sound amplifier is perfect for working with a subwoofer. The STK4050 chip has protection that prevents clicks from occurring when power is applied or turned off. There is also highly effective protection against short circuit in the load and from exceeding the temperature component.
Universal scheme
The circuit of this device is universal in that the circuit itself cannot be changed, but only the installation of microcircuits selected from the list proposed below. This makes it possible to modulate the power you need at the output of the UMZCH in the range from 6 W to 200 W. (All pictures can be enlarged by clicking)
The figure shows the relative placement of electronic elements on the signet:
It is well known that the hybrid microcircuits of the series proposed here guarantee solid output power and low THD. This makes it possible to extract from the amplifier the sound picture with the most high quality playback
The supply voltage of the device is bipolar, which ranges from 20v to 95v and is determined depending on the installed microcircuit (that is, according to the STK marking indicated in the table). The acoustics connected to the amplifier must have a resistance of 4 ohms; best option— 8 Ohm. The output resistance of the UMZCH is 55 kOhm. The quiescent current is within 120 mA. The output current reaches 15A, again depending on the installed STK, according to the table shown in the figure. For reliable operation hybrid integrated circuit STK4050 requires a heat sink with a cooling area of 400 cm2. To ensure efficient heat dissipation, the microcircuit is attached to the radiator through heat-conducting paste KPT-8.
On the chip STK4048XI. We offer a slightly modified circuit of this amplifier based on STK chips. If the circuit itself remains unchanged, and only the microcircuits from the list below are replaced, you can change the output power of the amplifier audio frequency depending on your needs from 6 to 200 watts. Depending on the marking STK chips they have different levels nonlinear distortion: II - 0.2%; V - 0.08%; X - 0.008%; XI - 0.002%.
Approximate layout of radio elements on a printed circuit board:
At all STK chips This series provides high output power and low nonlinear distortion. This allows you to get high quality sound reproduction from the amplifier.
The supply voltage is bipolar from 20 to 95 volts (varies depending on the brand of the microcircuit, see table). Amplifier load is at least 4 ohms; optimal - 8 ohms. The input impedance of the UMZCH is 55 kOhm. The quiescent current is 120 mA. Output current up to 15 amperes (depending on the microcircuit used, see table). Microcircuits of the STK40** series require the use of a radiator with an area of at least 400 mm 2. To effectively remove heat, you can screw the chip onto a heat sink using heat-conducting paste.
The list of microcircuits in the table would be incomplete without mentioning 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 not lower than 66 volts, and the maximum is 95 V.
Assembled amplifier based on STK4050 with an output power of 200 watts:
- 08.10.2014
The stereo volume, balance and tone control on the TCA5550 has the following parameters: Low nonlinear 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 adjustment range -14...+14dB Balance adjustment range 3dB Difference between channels 45dB Signal to noise ratio...
- 29.09.2014
Schematic diagram transmitter is shown in Fig. 1. The transmitter (27 MHz) produces a power of about 0.5 W. A 1 m long wire is used as an antenna. The transmitter consists of 3 stages - a master oscillator (VT1), a power amplifier (VT2) and a manipulator (VT3). The frequency of the master oscillator is set square. resonator Q1 at a frequency of 27 MHz. The generator is loaded on the circuit...
- 28.09.2014
Amplifier parameters: Total range of reproduced frequencies 12...20000 Hz Maximum output power of mid-high frequency channels (Rn=2.7 Ohm, Up=14V) 2*12 W Maximum output power of low-frequency channel (Rn=4 Ohm, Up=14V) 24 W Nominal power mid-range HF channels at THD 0.2% 2*8W Rated power of the LF channel at THD 0.2% 14W Maximum current consumption 8 A In this circuit, A1 is an HF-MF amplifier, and ...
- 30.09.2014
The VHF receiver operates in the range 64-108 MHz. The receiver circuit is based on 2 microcircuits: K174XA34 and VA5386; in addition, the circuit contains 17 capacitors and only 2 resistors. Oscillatory circuit one, heterodyne. A1 has a superheterodyne VHF-FM without ULF. The signal from the antenna is supplied through C1 to the input of the IF chip A1 (pin 12). The station is tuned in...
In the early 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 tape recorder and a radio receiver. The power amplifier and transformer remained operational.
Electrical diagram music center AIWA ZM-2900 can be downloaded from the attachment.
Of all electrical diagram I was interested in the STK419-150 stereo power amplifier, which provided decent power (about 100 W per channel) and good sound quality.
The connection diagram for integrated amplifiers STK419-110, STK419-130, STK419-140 and STK419-150 is shown below.
Resistances R13 and R14 (with a power dissipation of at least 2 W) determine the level of current limitation through the output transistors of the integrated assembly. Inductors L1 and L2 are made by winding one layer of copper coil wire with a diameter of 0.8 - 0.9 mm onto 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.
| Parameters of integrated amplifiers: | 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 (Iо) | mA | 60 | 60 | 60 | 60 | |
| Maximum power output (Poutmax) | W | 2x50 | 2x60 | 2x80 | 2x100 | |
| Nominal load resistance (Routnom) | Ω | 6 | 6 | 6 | 6 | |
| Frequency range (Bw) | kHz | 0,020-50 | 0,020-50 | 0,020-50 | 0,020-50 | |
| Input resistance (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 |
To manufacture the power supply of the amplifier, 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 terminal (0V), with leads for powering the final stages (20V each) and a voltage amplifier (50V each). The power supply diagram is shown below.
Subjectively, the amplifier sounds more pleasant than the LM3886.
I hope that this information regarding integrated circuits STK419-110, STK419-130, STK419-140 and STK419-150 will be useful for making your own stereo amplifiers.
Best regards,
