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| Audio Preamplifier with balance loudness controls |
5/15/2015
This receiver uses an IR-sensitive phototransistor (Clairex, HP, etc.) mounted in a light-tight enclosur
e with an aperture for the incoming IR beam. An optical system can be used with this receiver for increased range. A 741 amplifies the pulsed IR signal and a 565 PLL FM demodulator recovers the audio, which drives an LM386 audio amplifier and speaker.
e with an aperture for the incoming IR beam. An optical system can be used with this receiver for increased range. A 741 amplifies the pulsed IR signal and a 565 PLL FM demodulator recovers the audio, which drives an LM386 audio amplifier and speaker.
5/04/2015
STK4221 general description:
The STK4221II IC from SANYO is a dual high power amplifier chip, preferably suited for compact high power audio applications, for example in cars and luxury transport vehicle audio systems. The chip provides a hassle free stereo output through a single package and a hand full of few external components, making the construction of this circuit rather easy and straightforward. However since the idea presented here does not include a CD or a memory card driver circuit, the input may be derived from readymade audio sources like an ipod, CD walkman, cellphone etc. The circuit discussed here is intended specifically for car audio applications and provides a simple alternative for
making a 100 watt car stereo amplifier circuit. The diagram may be understood with the following points: An RC network formed by R5, R6 and C3, C4 together helps to reduce and filter stray frequency interferences and is therefore included at the input of the amplifiers. Capacitors C5 and C6 are the coupling capacitors used for blocking DC. The values of these capacitors are chosen such that it does not introduce high reactance levels at low frequencies. This particularly helps to reduce the influence of the input interference noises over the signal source resistance. The value of these capacitors may also be optimized for reducing the “pop” noise when power is switched ON.
STK4221 features:
- Quiescent current ICCO VCC = ±54V 20 40 100 mA
- Output power POTHD = 0.4%, f = 20Hz to 20kHz 80 W
- Total harmonic distortion THD PO = 1.0W, f = 1kHz 0.3 %
- Frequency response fL, fH PO = 1.0W, dB 20 to 50k Hz
- Input impedance ri PO = 1.0W, f = 1kHz 55 kΩ
- Output noise voltage VNO VCC = ±54V, Rg = 10kΩ 1.2 mVrms
- Neutral voltage VN VCC = ±54V -70 0 +70 mV
- Muting voltage VM -2 -5 -10 V
STK4221 circuit diagram:
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| STK4221 Audio Amplifier 2x80w |
STK4221 pcb layout:
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| STK4221 Audio Amplifier 2x80w |
TDA1015 general description:
The TDA1015 is a monolithic integrated audio amplifier circuit in a 9-lead single in-line (SIL) plastic package. The device is especially designed for portable radio and recorder applications and delivers up to 4 W in a 4Ω load impedance. The very low applicable supply voltage of 3,6 V permits 6 V spplications.
TDA1015 features:
- single in-line (SIL) construction for easy mounting
- separated preamplifier and power amplifier
- high output power
- thermal protection
- high input impedance
- low current drain
- limited noise behaviour at radio frequencies
TDA1015 reference data:
- Supply voltage range VP 3,6 to 18 V
- Peak output current IOM max. 2,5 A
- Output power at dtot= 10%
- VP = 12 V; RL = 4 Ω Po typ. 4,2 W
- VP = 9 V; RL = 4 Ω Po typ. 2,3 W
- VP = 6 V; RL = 4 Ω Po typ. 1,0 W
- Total harmonic distortion at Po = 1 W; RL = 4 Ω dtot typ. 0,3 %
- Input impedance preamplifier (pin 8) |Zi | > 100 kΩ power amplifier (pin 6) |Zi| typ. 20 kΩ
- Total quiescent current Itot typ. 14 mA
- Operating ambient temperature Tamb −25 to + 150 °C
- Storage temperature Tstg −55 to + 150 °C
TDA1015 circuit diagram:
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| Circuit diagram TDA1015 Audio Amplifier 1x4W |
TDA7490 general description:
The TDA7490 is a dual audio class D amplifier assembled in Flexiwatt 25 package; it is specially designed for high efficiency application mainly for TV and Home Stereo sets. TDA7490 Audio Amplifier 2 x 25W / 1 x 50W
TDA7490 features:
- 25W + 25W OUTPUT POWER:
- RL = 8Ω/4Ω; THD = 10%
- HIGH EFFICIENCY
- WIDE SUPPLY VOLTAGE RANGE (FROM
- ±10 TO ±25V)
- SPLIT SUPPLY
- TURN OFF/ON POP FREE
- ST-BY AND MUTE FEATURES
- SHORT CIRCUIT PROTECTION ACROSS
- THE LOAD
- THERMAL OVERLOAD PROTECTION
- EXTERNALLY SINCHRONIZABLE
- BRIDGE CONFIGURATION
TDA7490 sterio circuit diagram:
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| TDA7490 Audio Amplifier 2 x 25W / 1 x 50W circuit diagram |
TDA7490 mono circuit diagram:
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| TDA7490 Audio Amplifier 2 x 25W / 1 x 50W mono circuit diagram |
TDA7490 sterio circuit pcb:
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| TDA 7490 pcb layout |
4/29/2015
TDA7594 general description:
The Type IC TDA7294 from SGS-Thomson is an integrated a.f. amplifier intended for use in all sorts of hi-f application. According to the manufacturer's data sheets, chip can deliver outputs of up to 100 watt. Considering other properties, such as low noise, low distortion and reliable short-circuit and thermal protection circuits as well, the chip is indeed an interesting one. Moreover, with peak supply voltages of ±40 V and a load impedance of 4 ohm, the maximum dissipation of the IC TDA7294 will easily be exceeded. For these reasons, the supply in the present amplifier has been kept down to a safe ±30 V. At these voltages, the chip delivers, without any difficulty, 50 W into an 8 ohm load and 80 W into a 4 ohm load. These are still very respectable figures, particularly in view of the reasonable IC price. The circuit diagram of the amplifier in shows that the IC TDA7294 needs only a small number of external components. The input signal is applied to pin 3 via capacitor C1 and low-pass filter R6-C10. The filter improves the pulse response and flattens the frequency response. For maximum output offset, the values of R1 and R3 should be equal, so that the input impedance is 10k. The roll-off frequencies of R1-C1 and R2-C2 determine the lower bandwidth limit of the amplifier: with values a specified, this is about 16 Hz. The upper -3 dB point is at about 100 kHz.The amplifier is muted by a relevant input to pin 10 and placed in the stand-by mode by a relevant signal at pin 9. Muting should always take place before the stand-by mode is selected. Connecting the mute and standby pins permanently to the supply line ensures that the amplifier comes on immediately the power is switched on. Any switch-on clicks may be eliminated by increasing time constants R3-C4 and R5-C5. If large-value electrolyte capacitors are used in the power supply, switching off will be rather slow. It is best to build the amplifier on the printed-circuit board shown below. Insulating material between the heat sink and the IS is. The amplifier will have good performance with toroidal mains transformer, a 25A bridge rectifier and two 10.000uf,50 V electrolytic capacitors.
TDA7594 Circuit diagram:
MUTE and ST-BY utilization:
Datasheet for TDA7594: Download - No
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