Showing posts with label Mini Amplifier. Show all posts
Showing posts with label Mini Amplifier. Show all posts
Saturday, April 23, 2011
This is 4 Watt Amplifier Circuit Diagram for portable radio application using TDA1011 from Philips Semiconductor.
The TDA1011 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 4 W load impedance. The device can deliver up to 6 W into 4 W at 16 V loaded supply in mains-fed applications. The maximum permissible supply voltage of 24 V makes this circuit very suitable for d.c. and a.c. apparatus, while the very low applicable supply voltage of 3,6 V permits 6 V applications.
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| Skema Rangkaian TDA1011 - 4W Audio Amplifier |
Wednesday, March 2, 2011
Here is a 3 Watt stereo amplifier circuit using MAX 7910 IC. The MAX9710 a stereo audio power amplifier IC capable of delivering 3Watts of out put to 4 Ohm loads. MAX9710 can be operated from a single 4.5V to 5.5V power supply , makes it ideal for hand held applications.The IC also features thermal overload protection.
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| Skema Rangkaian 3 Watt Stereo Amplifier MAX 7910 |
This amplifier circuit is suitable for small power audio devices such as radio sets and portable CD players. 5 V DC power supply is used for powering the circuit. 6V battery with an IN 4007 diode series to the positive terminal of it can also be used instead of 5 V DC supply. The circuit will get a supply voltage approximately 5 V after 0.7 V voltage drop across diode.
Thursday, December 9, 2010
Rangkaian 1W Amplifier TDA 7053
This is a 1 watt stereo audio amplifier circuit using IC TDA 7053 from Philips. It is particularly suited to battery operation, providing 1 watt per channel from only a 6V DC supply. It will operate best from 6 – 12 V DC and requires no heat-sink for normal use.
This is a 1 watt stereo audio amplifier circuit using IC TDA 7053 from Philips. It is particularly suited to battery operation, providing 1 watt per channel from only a 6V DC supply. It will operate best from 6 – 12 V DC and requires no heat-sink for normal use.
Rangkaian TDA 7053 Stereo Audio AmplifierThe TDA7053 Integrated Circuit does nearly all the work, so there are only a few external components. C1 and C2 provide power supply decoupling or filtering. R1 and R2 provide a DC ground reference for the input signals, and may be increased if your source requires a higher load impedance. Do not use more than 100k ohms.
Since the amplifier circuit in BTL configuration, the outputs are floating with respect to ground. Therefore NO output leads should be connected to ground. The Philips data sheet contains all the necessary information about the TDA7053.
Since the amplifier circuit in BTL configuration, the outputs are floating with respect to ground. Therefore NO output leads should be connected to ground. The Philips data sheet contains all the necessary information about the TDA7053.
For more details please download the datasheet at:
http://www.quasarelectronics.com/3107.htm
This is 2x1W mini audio amplifier circuit using IC KA2209. It will operate well from 3-12V DC and will work from a battery since the quiescent current drain is low. It requires no heat sink for normal use. The input and output are both ground referenced. Maximum output will be obtained with a 12V power supply and 8 ohm speaker, however it is particularly suitable for driving headphones from a supply as low as 3V
The mini amplifier circuit only a few external components, the IC contains most of the necessary circuitry. R1,R2 and R3,R4 are the feedback resistors. C1 provides power supply decoupling. C2 and C3 are the input coupling capacitors, which block any DC that might be present on the inputs. C4,C5 block DC in the feed back circuit from the inverting inputs, and C6,C7 are the output coupling capacitors. C8, R5 and C9,R6 act as zobel networks providing a high frequency load to maintain stability at frequencies where loud speaker inductive reactance may become excessive. The pot provides adjustable input level attenuation.
KA2209 - Audio Amplifier Circuit Component
C1,C2,C3 : 10 uF/25V ecap
C4,C5 : 100 uF/16V ecap
C6,C7 : 470 uF/16V ecap
C8,C9 : 100 nF poly
R1,R3 : 1k Resistor
R2,R4 : 100R Resistor
R5,R6 : 4R7ohm Resistor
Pot1 : 10k dual gang log pot
IC1 : KA2209 Integrated Circuit
Sunday, December 5, 2010
Using the LM1877 chip can be designed a very simple audio amplifier circuit for small audio applications like portable devices . This audio amplifier circuit capable of delivering 2 Watt per channel continuous into 8Ω loads.
Rangkaian Stereo Amplifier 2W (LM1877) The LM1877 is a monolithic dual power Amplifier designed to deliver 2W/channel continuous into 8 loads. The LM1877 is designed to operate with a low number of external components, and still provide flexibility for use in stereo phonographs, tape recorders and AM-FM stereo receivers, etc. Each power Amplifier is biased from a common internal Regulator to provide high power supply rejection, and output Q point centering. The LM1877 is internally compensated for all gains greater than 10.
LM1877 Chip Features
- 2W/channel
- −65 dB ripple rejection, output referred
- −65 dB channel separation, output referred
- Wide supply range, 6V–24V
- Very low cross-over distortion
- Low audio band noise
- AC short circuit protected
- Internal thermal shutdown
Saturday, December 4, 2010
Here’s a circuit of 7 Watt audio amplifier that is very simple and very easy to build. This amplifier is built using TBA810 as the main component with the support of a few passive components. This circuit can work well, kits and components of this circuit can be found easily at an electronics store in your area.
Rangkaian TBA810 - 7 Watt audio amplifier
IC TBA810 PinningThe TBA810 chip is a class B amplifier with high efficiency and very low harmonic distortion . The input voltage range of the TBA810 is from 4 volts to 20 volts . Main features of the TBA810 circuit are : low noise , few external components required , polarity inversion protection , high supply voltage rejection ( 40dB min.) . TBA810 monolithic audio amplifier can be used in many audio applications for car radios ,other audio devices or portable applications .
Here is circuit of Mini amplifier 1.2 watt will use TBA820M chip, The TBA820M chip features a very low minimum working supply voltage of 3V, low quiescent current, good ripple rejection, no crossover distortion and low power dissipation. Maximum supply voltages is 16 Volts into 16 Ohms speaker, 12Volts into 8 Ohms and 9Volts into 4 Ohms.
Rangkaian TBA820M Mini Amplifier 1.2 Watt
TBA820M IC pinningThe work of the circuit, feed power supply 9Volt reach the circuit LED1 will stick bright tell the event works of the circuit. Which C7 will voltage filter smoothly then feed, power supply , give with IC1. At pin 6 when feed input sound signal reaches pin 3 ways s of IC1. by have C1,R1,R2 perform coupling and decrease signal sound level just rightly. The part of pin 2 of IC1 have R3 and C2 perform fix the expansion ratio and enhance the stability of tall frequency improve. From that time a signal had that to enlarged then change go out pin 5 ways s of IC1 change C4 coupling signals go to still a loudspeaker. By have R4 and C5 perform eradicate the noise goes out.
Wednesday, November 24, 2010
This is a circuit schematic for the mini power amplifer using TDA1015T, based on the application circuit from the datasheet. Not many external components are needed to complete at full 0.5W power amplifier. This is without its pre-amp but not many more components are required to add that to the circuit.
Rangkaian Mini Amplifier TDA1015TA volume control is included in schematic. Log type is required and 4k7 to 10k is about right. A dual pot is needed if you plan on using two TDA1015's to complete a stereo amp.
Chances are you'll want this amplifier portable. Batteries do the trick fine, but you won't get much power out of a couple of 1.5V cells. Unfortunately the size of a decent amount of battery power will mean that the overall size of this amp will be much bigger and for that there are more benefits to be had using a device like the TDA7052 or TDA2822 for stereo.
Chances are you'll want this amplifier portable. Batteries do the trick fine, but you won't get much power out of a couple of 1.5V cells. Unfortunately the size of a decent amount of battery power will mean that the overall size of this amp will be much bigger and for that there are more benefits to be had using a device like the TDA7052 or TDA2822 for stereo.
Quick ref data of TDA1015T Chip
- Supply voltage range: 3,6 to 12 V
- Peak output current: 1 A
- Output power: 0,5 W
- Voltage gain power amplifier: 29 dB
- Voltage gain preamplifier: 23 dB
- Total quiescent current: 22 mA
- Operating ambient temperature range: -25 to +150 °C
- Storage temperature range: -55 to + 150 °C
This is a small amplifier using TDA2822 chip designed for portable cassette players and radios. Including volume control. A 9 volt power supply is ideal for supply, which can be a source with batteries or transformer. It is not necessary to use heat sink.
Rangkaian TDA2822 Mini Portable AmplifierGeneral integrated amplifier circuit external components and need more larger heatsink. This paper presents a simple amplifier circuit, made easy. TDA2822 amplifier integrated circuits used in music players, portable DVD and other audio playback; power is not great but you can satisfy the requirements of the hearing, and the circuit is simple, good sound quality, wide voltage range of characteristics such as the amateur production Small amp better choice.
Feature of TDA2822 Amplifier Circuit
- Power Supply: 3 – 12 V at 200 – 500 mA max
- Idle Current: ~ 10 mA
- Output impedance 4 - 32 Ohm
- Freq. response ~ 40 Hz to 200 kHz, 8 ohm, G=10<> 50 kHz, 32 ohm
- Output Power:
- > 1 Watt max. 4-8 ohms, 12V DC
- > 500 mW, 32 ohm, 12V
- > 500 mW, 4 ohm, 6V
- ~ 0.4 Watt RMS cont. per channel
Saturday, August 28, 2010
This audio amplifier circuit, connected to 32 Ohm impedance mini-earphones, can detect very remote sounds. Useful for theatre, cinema and lecture goers: every word will be clearly heard. You can also listen to your television set at a very low volume, avoiding to bother relatives and neighbors. Even if you have a faultless hearing, you may discover unexpected sounds using this device: a remote bird twittering will seem very close to you.
Skema Rangkaian 1,5V Earphones Audio AmplifierThe heart of the circuit is a constant-volume control amplifier. All the signals picked-up by the microphone are amplified at a constant level of about 1 Volt peak to peak. In this manner very low amplitude audio signals are highly amplified and high amplitude ones are limited. This operation is accomplished by Q3, modifying the bias of Q1 (hence its AC gain) by means of R2.
A noteworthy feature of this circuit is 1,5V battery operation.
Typical current drawing: 7,5mA.
A noteworthy feature of this circuit is 1,5V battery operation.
Typical current drawing: 7,5mA.
List Component
- P1: 22K Log. Potentiometer
- R1,R9: 10K 1/4W Resistors
- R2: 1M 1/4W Resistor
- R3: 4K7 1/4W Resistor
- R4,R7: 100K 1/4W Resistor
- R5: 3K9 1/4W Resistor
- R6: 1K5 1/4W Resistor
- R8: 100R 1/4W Resistor
- C1,C2: 100nF 63V Polyester or Ceramic Capacitors
- C3,C6: 1µF 63V Polyester or Ceramic Capacitors
- C4: 10µF 25V Electrolytic Capacitor
- C5: 470µF 25V Electrolytic Capacitor
- D1: 1N4148 75V 150mA Diode
- Q1,Q2,Q3: BC547 45V 100mA NPN Transistors
- Q4: BC337 45V 800mA NPN Transistor
- MIC1: Miniature electret microphone
- SW1: SPST Switch
- J1: Stereo 3mm. Jack socket
- B1: 1.5V Battery
Source
Saturday, May 22, 2010
45 Watt Class B amplifier Circuit of this very simple , straightforward but Rugged circuit, though intended for any high quality audio applications and, above all, to complete the series of articles recently started forming the Modular Preamplifier Control Center, is well suited Also to make a very Good Guitar or Bass amplifier
Note
- Power transistors Q8 and Q9 Can be Used satisfactorily: 2N3055/MJ2955, TIP3055/TIP2955, TIP35/TIP36, MJ802/MJ4502 amongst others.
- Power transistors Q8 and Q9 Should be mounted on a black, finned heatsinks as usual.
- Output power (1KHz sinewave): 45 Watt RMS into 8 Ohms - 69W RMS into 4 Ohms
- Sensitivity: 0.81V RMS input for 45W output
- Frequency response @ 1W RMS: 15Hz to 23KHz -0.2dB
- Total harmonic distortion @ 1KHz: 1W 0.008% 20W 0.008% 45W 0.016%
- Total harmonic distortion @10KHz: 1W 0.01% 20W 0.015% 45W 0.025%
- Unconditionally stable on capacitive loads
- R1: 18K
- R2: 3K9
- R3,R6: 1K
- R4: 2K2
- R5: 15K
- R7: 22K
- R8: 330R
- R9,R10: 10R
- R11,R12: 47R
- R13: 10R/1 Watt
- C1: 1µF/63V
- C2: 470pF/63V
- C3: 47µF/25V
- C4: 15pF/63V
- C6: 220nF/100V
- C6: 100nF/63V
- D1,D2,D3,D4: 1N4148
- Q1,Q2: BC560C
- Q3,Q4: BC556
- Q5: BC546
- Q6: BD139
- Q7: BD140
- Q8: 2N3055
- Q9: MJ2955
Tuesday, May 18, 2010
This amplifier operates in Class AB mode with up to 2 watts of output power, the single 470R preset resistor controls the quiescent current PR1 flowing through the BD139/140 complimentary output transistors. Adjustment here, is a trade-off Between low distortion and low quiescent current. Typically, under quiescent conditions, current is about 15 mA, rising to 150 mA with a 50 mV input signal. The frequency response is shown below and is flat from 20Hz to 100kHz
PR1 470R controls the quiescent current flowing through the BD139/140 complimentary output transistors. Adjustment here, is a trade-off between low distortion and low quiescent current. Typically, under quiescent conditions, current is about 15 mA rising to 150 mA with a 50 mV input signal. The frequency response is shown below and is flat from 20Hz to 100kHz
This amplifier circuit is DC biased so that the emitters of the BD139 and BD140 are at approximately half supply voltage, to allow for a maximum output voltage swing. R9 and R10 provide a degree of temperature stabilization which works as follows. If the output transistors are warm, the emitter currents will increase. This causes a greater voltage drop across R9 and R10 reducing the available bias current. All four transistors are direct coupled which ensures:
This amplifier circuit is DC biased so that the emitters of the BD139 and BD140 are at approximately half supply voltage, to allow for a maximum output voltage swing. R9 and R10 provide a degree of temperature stabilization which works as follows. If the output transistors are warm, the emitter currents will increase. This causes a greater voltage drop across R9 and R10 reducing the available bias current. All four transistors are direct coupled which ensures:
- A good low frequency response
- Temperature and bias change stability.
Tuesday, December 15, 2009
Rangkaian 12 Volt Audio Amplifier
This circuit power amplifier was deliberately designed using no ICs and in a rather old-fashioned manner in order to obtain good harmonic distortion behavior and to avoid hard to find components. The amplifier(s) can be conveniently supplied by a 12V wall plug-in adapter. Closing SW1 a bass-boost is provided but, at the same time, volume control must be increased to compensate for power loss at higher frequencies. In use, R9 should be carefully adjusted to provide minimal audible signal cross-over distortion consistent with minimal measured quiescent current consumption; a good compromise is to set the quiescent current at about 10-15 mA.To measure this current, wire a DC current meter temporarily in series with the collector of Q3.
List Component
P1_____________10K Log.Potentiometer
R1,R2__________33K 1/4W Resistors
R3_____________33R 1/4W Resistor
R4_____________15K 1/4W Resistor
R5,R6___________1K 1/4W Resistors
R7____________680R 1/4W Resistor
R8____________120R 1/2W Resistor
R9____________100R 1/2W Trimmer Cermet
C1,C2__________10µF 63V Electrolytic Capacitors
C3____________100µF 25V Electrolytic Capacitor
C4,C7_________470µF 25V Electrolytic Capacitors
C5_____________47pF 63V Ceramic Capacitor
C6____________220nF 63V Polyester Capacitor
C8___________1000µF 25V Electrolytic Capacitor
D1___________1N4148 75V 150mA Diode
Q1____________BC560C 45V 100mA PNP Low noise High gain Transistor
Q2____________BC337 45V 800mA NPN Transistor
Q3____________TIP31A 60V 4A NPN Transistor
Q4 ___________TIP32A 60V 4A PNP Transistor
SW1___________SPST switch
Tuesday, December 8, 2009
Audio Amplifier 4 Transistor
The circuit a 4-transistor amplifier suitable for a variety of projects including receivers, intercoms, microphones, telephone pick-up coils, and general audio monitoring. The amplifier has a power isolation circuit and bandwidth limiting to reduce oscillations and “motorboating”. The values are not particularly critical and modest deviations from the indicated values will not significantly degrade the performance.
Three cell battery packs giving about 4.5 volts are recommended for most transformerless audio amplifiers driving small 8 ohm speakers. The battery life will be considerably longer than a 9 volt rectangular battery and the cell resistance will remain lower over the life of the battery resulting in less distortion and stability problems.
The amplifier may be modified to work with a 9 volt battery if desired by moving the output transistors’ bias point. Lowering the 33k resistor connected from the second transistor’s base to ground to about 10k will move the voltage on the output electrolytic capacitor to about 1/2 the supply voltage. This bias change gives more signal swing before clipping occurs and this change is not necessary if the volume is adequate.
Mini Amplifier Stereo 4.5 Volt - 5.5 Volt
This circuit is ideal for small power audio applications such as portable CD players or radio sets.The circuit has been designed strictly toward the ingredients and found to be working well.
MAX9710 Stereo Audio Power Amplifier IC capable of producing 3Watts and out, of which 4 Ohm loads. MAX9710 uses a single 4.5V to 5.5V Power Thurs It is ideal for the provision of the manual is also applications.The IC Thermal overload protection.
This circuit is ideal for small power audio applications such as portable CD players or radio sets.The circuit has been designed strictly toward the ingredients and found to be working well.
MAX9710 Stereo Audio Power Amplifier IC capable of producing 3Watts and out, of which 4 Ohm loads. MAX9710 uses a single 4.5V to 5.5V Power Thurs It is ideal for the provision of the manual is also applications.The IC Thermal overload protection.
Use a 5 V DC power supply for powering the circuit. f you want to use a battery ,then use a 6V battery with a IN 4007 diode series to the positive terminal of it.The diode will drop 0.7 V and the IC will get the rated ~5V.This is just a saftey recommendation
Features IC MAX9710
* 3W into 3Ω (1% THD+N)
* 4W into 3Ω (10% THD+N)
* Industry-Leading, Ultra-High 100dB PSRR
* PC99/01 Compliant
* Patented Click-and-Pop Suppression
* Low 0.005% THD+N
* Low Quiescent Current: 7mA
* Low-Power Shutdown Mode: 0.5µA
* MUTE Function
* Tiny 20-Pin Thin QFN (5mm x 5mm x 0.8mm)
3 Volt - 6 Volt Mini Audio Amplifier
Here is a mini 2W audio amplifier is suitable for small handheld radios and other portable audio gadgets. The amplifier circuit can be run from 3Volt. This Mercury is ideal for battery operated module.
Here is a mini 2W audio amplifier is suitable for small handheld radios and other portable audio gadgets. The amplifier circuit can be run from 3Volt. This Mercury is ideal for battery operated module.
Skema Rangkain 3 Volt - 6 Volt Mini Audio Amplifier
The potentiometer circuit can be used to control volume. Capacitor C1 and C2 are designed to filter supplyvoltage If the battery separator is used as operations offer source.For using batteries C1 and C2 are not required.
IC TDA7052 is a mono output amplifier in 8-comng Head DI package (DIP). The device is designed primarily for battery-operated portable audio circuits. Features include TDA 7052, no external components needed, no switch-on or switch-off button sounds great overall stability and very low power consumption (quiescent current of 4 mA), low THD, it is not necessary any cooler and short-circuit proof.
Profit TDA 7052 is set internally at 40 dB. . Compensate for the reduction of output power due to low voltage TDA7052 uses Bridge-Tied-Load principle
(BTL), which can provide power about 1 to 2 W RMS (THD = 10%), 8 ohm load to the power supply 6 V.
Monday, December 7, 2009
Audio Amplifier with Bass-boost
As the amplifier circuit is also used to move a number of frequency loudspeaker, the volume of the bass frequencies will be reduced. Therefore it is necessary to set the bass-boost controls on fedback loop amplifier, this is done to address the decline in quality. Graph bass can reach a maximum of +16.4 dB @ 50Hz.
Note:
This circuit can be connected directly to a CD player, tuner, and tape recorders.
Transistor Q3 and Q4 must be in pairs with the heatsink.
Adjust the volume control on the minimum and R3 position with a minimum value of resistance as well. try to switch the circuit set in R3 to read the flow of about 20 to 25mA. Wait for 15 minutes, connect the ground of A1, P1, C2, C3dan C4. Connect the output also C9 ground
List Component
P1 : 22K Log Potemsiometer (Dual gang for stereo)
C3, 4 : 470uF/25V
P2 : 100K Log Potemsiometer (Dual gang for stereo)
C6 : 47pF 63V ceramic ar polyester capasitor
R2, 4, 8 : 820R 1/4W
C7 : 10nF 63V polyester capasitor
R1 : 4K7 1/4W
C9 : 100nF 63V polyester capasitor
R3 : 500R 1/2W
D1 : 1N4148 75V 150mA Diode
R5 : 82K 1/4W
IC 1 : NE5532 Low noise Dual Op-amp
R6, 7 : 47K 1/4W
Q1 : BC547B 45V 100mA NPN Transitor
R9 : 10R 1/2W
Q2 : BC557B 45V 100mA PNP Transitor
R10 : 0,22 4W(wirewound)
Q3 : TIP42A 60V 6A PNP Transistor
C1, 8 : 470nF 63V polyester capasitor
Q4 : TIP41A 60V 6A NPN Transistor
C2, 5 : 100uF/25V J1 : RCA audio input socket
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Tuesday, November 17, 2009
Some lovers of High Fidelity headphone listening prefer the use of battery powered headphone amplifiers, not only for portable units but also for home "table" applications. This design is intended to fulfil their needs and its topology is derived from the Portable Headphone Amplifier featuring an NPN/PNP compound pair emitter follower output stage. An improved output driving capability is gained by making this a push-pull Class-B arrangement. Output power can reach 100mW RMS into a 16 Ohm load at 6V supply with low standing and mean current consumption, allowing long battery duration.
The single voltage gain stage allows the easy implementation of a shunt-feedback circuitry giving excellent frequency stability.
The single voltage gain stage allows the easy implementation of a shunt-feedback circuitry giving excellent frequency stability.
P1_____________22K Dual gang Log Potentiometer (ready for Stereo)
R1_____________15K 1/4W Resistor
R2____________100K 1/4W Resistor
R3____________100K 1/2W Trimmer Cermet
R4_____________47K 1/4W Resistor
R5____________470R 1/4W Resistor
R6____________500R 1/2W Trimmer Cermet
R7______________1K 1/4W Resistor
R8,R9__________18K 1/4W Resistors
R10,R11_________2R2 1/4W Resistors
R12____________33R 1/4W Resistor
R13_____________4K7 1/4W Resistor
C1,C2__________10µF 25V Electrolytic Capacitors
C3,C5_________100nF 63V Polyester Capacitors
C4,C6_________220µF 25V Electrolytic Capacitors
Q1,Q2,Q5______BC560C 45V 100mA Low noise High gain PNP Transistors
Q3,Q4_________BC550C 45V 100mA Low noise High gain NPN Transistor
Q6____________BC327 45V 800mA PNP Transistor
Q7____________BC337 45V 800mA NPN Transistor
J1_____________RCA audio input socket
J2_____________6mm. or 3mm. Stereo Jack socket
B1_____________6V Battery
Notes:
- Before setting quiescent current rotate the volume control P1 to the minimum, Trimmer R6 to maximum resistance and Trimmer R3 to about the middle of its travel.
- Connect a suitable headphone set or, better, a 33 Ohm 1/2W resistor to the amplifier output.
- Switch on the supply and measure the battery voltage with a Multimeter set to about 10Vdc fsd.
- Connect the Multimeter across the positive end of C4 and the negative ground.
- Rotate R3 in order to read on the Multimeter display exactly half of the battery voltage previously measured.
- Switch off the supply, disconnect the Multimeter and reconnect it, set to measure about 10mA fsd, in series to the positive supply of the amplifier.
- Switch on the supply and rotate R6 slowly until a reading of about 3mA is displayed.
- Check again the voltage at the positive end of C4 and readjust R3 if necessary.
- Wait about 15 minutes, watch if the current is varying and readjust if necessary.
- Those lucky enough to reach an oscilloscope and a 1KHz sine wave generator, can drive the amplifier to the maximum output power and adjust R3 in order to obtain a symmetrical clipping of the sine wave displayed.
In recent years, following CD's introduction, vinyl recordings are almost disappeared. Nevertheless, a phono preamplifier is still useful for listening old vinyl discs from a well preserved collection. This simple but efficient circuit devised for cheap moving-magnet cartridges, can be used in connection with the audio power amplifiers shown in these webpages, featuring low noise, good RIAA frequency response curve, low distortion and good high frequency transients behavior due to passive equalization in the 1 to 20KHz range. Transistors and associated components provide ±18V supply to the op-amp, improving headroom and maximum output voltage.
Component List Of Phono Amplifier
R1_________47K 1/4W Resistor
R2________100R 1/4W Resistor
R3__________6K8 1/4W Resistor
R4_________68K 1/4W Resistor
R5,R6_______2K7 1/4W Resistor
R7__________2K2 1/4W Resistor
R8_________39K 1/4W Resistor
C1-C3_____100µF 25V Electrolytic Capacitors
C4,C5______47nF 63V Polyester Capacitors 5% tolerance
D1,D2__BZX79C18 18V 500mW Zener Diodes
IC1_______LM833 Low noise Dual Op-amp
Q1________BC337 45V 800mA NPN Transistor
Q2________BC327 45V 800mA PNP Transistor
Notes:
- R2, R3, R4, R7, R8, C4 & C5 should be low tolerance types.
- Schematic shows left channel and power supply.
- For stereo operation R1, R2, R3, R4, R7, R8; J1; C1, C4 & C5 must be doubled.
- Numbers in parentheses show IC1 right channel pin connections.
This circuit of audio amplifier push-pull single-ended Class A is capable of providing a sound comparable to those valve amplifiers, delivering more output power (6.9W measured across a 8 Ohm loudspeaker cabinet load), less THD, higher input sensitivity and better linearity.
Voltage and current required for this circuit are 24V and 700mA respectively. The only penalty for the transistor operated circuit is the necessity of using a rather large heatsink for Q2 and Q3. In any case, the amount of heat generated by this circuit can be comparable to that of a one-valve amplifier. An optional bass-boost facility can be added, by means of R5 and C5.
Voltage and current required for this circuit are 24V and 700mA respectively. The only penalty for the transistor operated circuit is the necessity of using a rather large heatsink for Q2 and Q3. In any case, the amount of heat generated by this circuit can be comparable to that of a one-valve amplifier. An optional bass-boost facility can be added, by means of R5 and C5.
Component list of audio amplifier kelas A
P1_____________47K Log. Potentiometer (Dual-gang for stereo)
R1____________100K 1/4W Resistor
R2_____________12K 1/4W Resistor (See Notes)
R3_____________47K 1/4W Resistor
R4______________8K2 1/4W Resistor
R5______________1K5 1/4W Resistor (Optional, see Notes)
R6______________2K7 1/4W Resistor
R7,R9_________100R 1/4W Resistors
R8____________560R 1/2W Resistor (See Notes)
R10_____________1R 1/2W Resistor
C1,C2__________10µF 63V Electrolytic Capacitors
C3_____________47µF 25V Electrolytic Capacitor
C4____________100µF 35V Electrolytic Capacitor
C5____________150nF 63V Polyester Capacitor (Optional, see Notes)
C6,C7_________220µF 25V Electrolytic Capacitors
C8___________1000µF 25V Electrolytic Capacitor
Q1___________BC560C 45V 100mA Low noise High gain PNP Transistor
Q2,Q3________BD439 60V 4A NPN Transistors
Notes:
- If necessary, R2 can be adjusted to obtain 13V across C8 positive lead and negative ground.
- Total current drawing of the circuit, best measured by inserting the probes of an Avo-meter across the positive output of the power supply and the positive rail input of the amplifier, must be 700mA. Adjust R8 to obtain this value if necessary.
- Q2 and Q3 must be mounted on a finned heatsink of 120x50x25mm. minimum dimensions.
- Add R5 and C5 if the bass-boost facility is required.
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