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.
Monday, November 16, 2009
This circuit was designed to produce high quality and powerful audio power amplifier that would provide 60W-90W power output.
Skema Rangkaian Mosfet Audio Amplifier
Daftar Component Audio Amplifier Mosfet The transistors Q6 & Q7 should be fitted on a small and U-shaped heatsink while a larger heatsink is used to mount the transistors Q8 & Q9. For the regulation of voltage, the trimmer R10 is set to its minimum resistance which is made possible when powering ON the amplifier and then adjusting R10 until the drawing of the current reaches about 120 mA to 130 mA. If necessary, the current will need to be readjusted when after 15minutes, the current keeps on varying.
The circuit power supplay suggested value for capacitors C1 & C2 should be at the required minimum for a mono amplifier. The capacitance values may be increased up to 10000 uF when used in stereo configurations to achieved optimum performance. To eliminate ground loops and hums, an appropriate grounding is very essential. This will be done by connecting R1, R3, C2, C3, & C4 to the same point of the ground sides and the ground input wire while in the output ground, C7-C11 & R7 will be connected. Finally, the input and output grounds will be connected separately to the power supply ground.
The circuit power supplay suggested value for capacitors C1 & C2 should be at the required minimum for a mono amplifier. The capacitance values may be increased up to 10000 uF when used in stereo configurations to achieved optimum performance. To eliminate ground loops and hums, an appropriate grounding is very essential. This will be done by connecting R1, R3, C2, C3, & C4 to the same point of the ground sides and the ground input wire while in the output ground, C7-C11 & R7 will be connected. Finally, the input and output grounds will be connected separately to the power supply ground.
This is circuit of Audio Power Amplifier use IC TDA2005, the circuit suitable for Car amplifier cos used supply 12Volt. The IC TDA2005 is class B dual audio power amplifier package specifically designedfor car radio application : power booster amplifiers are easily designed using this device that provides a high current capability (up to 3.5 A) and that can drive very low impedance loads
Skema Rangkaian CAR Audio Power Amplifier 12 Volt
used a well designed quality transformer to get less noise. It will be another good way to use a sufficient battery to power the circuit. Keep the supply wires as short as possible. Input source should be isolated from the external noises too. It is recommended to use coaxial cable to connect the input audio.
Absolute Maximum Rating IC TDA2005
Operating Supply Voltage......................... 18 V
DC Supply Voltage................................ 28 V
Peak Supply Voltage (for 50 ms).................. 40 V
Output Peak Current (non repetitive t = 0.1 ms).. 4.5 A
Output Peak Current (repetitive f . 10 Hz)....... 3.5 A
Power Dissipation at Tcase = 60 °C............... 30 W
Storage and Junction Temperature................. – 40 to 150 °C.
Sunday, November 15, 2009
This is a circuit of an audio amplifier for the guitar. This circuit can reproduce a Combo amplifier of the type very common in the 'Sixties and the' Seventies of the past century. It is well suited as a guitar amplifier but it will do a good job with any kind of electronic musical instrument or microphone.
5W power output was a common feature of these widespread devices due to the general adoption of a class A single-tube output stage (see the Vox AC-4 model). Furthermore, nowadays we can do without the old-fashioned streetcars VIB-feature frequently included in those designs.
P1______________4K7 Linear Potentiometer
P2_____________10K Log. Potentiometer
R1,R2__________68K 1/4W Resistors
R3____________220K 1/4W Resistor
R4,R6,R11_______4K7 1/4W Resistors
R5_____________27K 1/4W Resistor
R7______________1K 1/4W Resistor
R8______________3K3 1/2W Resistor
R9______________2K 1/2W Trimmer Cermet
R10___________470R 1/4W Resistor
R12_____________1K5 1/4W Resistor
R13___________470K 1/4W Resistor
R14____________33K 1/4W Resistor
C1____________100pF 63V Ceramic Capacitor
C2____________100nF 63V Polyester Capacitor
C3____________470µF 35V Electrolytic Capacitor
C4____________220nF 63V Polyester Capacitor (Optional, see Notes)
C5_____________47µF 25V Electrolytic Capacitor (Optional, see Notes)
C6______________1µF 63V Polyester Capacitor
C7,C8,C9,C10___47µF 25V Electrolytic Capacitors
C11____________47pF 63V Ceramic Capacitor
C12__________1000µF 35V Electrolytic Capacitor
C13__________2200µF 35V Electrolytic Capacitor
D1_____________5mm. Red LED
D2,D3________1N4004 400V 1A Diodes
Q1,Q2________2N3819 General-purpose N-Channel FETs
Q3____________BC182 50V 200mA NPN Transistor
Q4____________BD135 45V 1.5A NPN Transistor (See Notes)
Q5____________BDX53A 60V 8A NPN Darlington Transistor
Q6____________BDX54A 60V 8A PNP Darlington Transistor
J1,J2________6.3mm. Mono Jack sockets
SW1____________1 pole 3 ways rotary switch (Optional, see Notes)
SW2____________SPST Mains switch
F1_____________1.6A Fuse with socket
T1_____________220V Primary, 48V Center-tapped Secondary
20 to 30VA Mains transformer
PL1____________Male Mains plug
SPKR___________One or more speakers wired in series or in parallel
Total resulting impedance: 8 or 4 Ohm
Minimum power handling: 20W
The present circuit can deliver 10W of output power when driving an 8 Ohm load, or about 18W @ 4 Ohm.It also features a two-FET Preamplifier, two inputs with different sensitivity, a treble-cut control and an optional switch allowing powerful overdrive or treble-enhancement.
This is 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.
Skema Rangkaian 4.5Volt Transistor Amplifier
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.
Subscribe to:
Posts (Atom)
