Showing posts with label headphone. Show all posts
Showing posts with label headphone. Show all posts
Thursday, November 6, 2014
Battery powered Headphone Amplifier
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.
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.
Battery-powered Headphone Amplifier Circuit Diagram:
- For a Stereo version of this circuit, all parts must be doubled except P1, SW1, J2 and B1.
- 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.
Output power (1KHz sinewave):
16 Ohm: 100mW RMS
32 Ohm: 60mW RMS
64 Ohm: 35mW RMS
100 Ohm: 22.5mW RMS
300 Ohm: 8.5mW RMS
Sensitivity:
160mV input for 1V RMS output into 32 Ohm load (31mW)
200mV input for 1.27V RMS output into 32 Ohm load (50mW)
Frequency response @ 1V RMS:
flat from 45Hz to 20KHz, -1dB @ 35Hz, -2dB @ 24Hz
Total harmonic distortion into 16 Ohm load @ 1KHz:
1V RMS (62mW) 0.015% 1.27V RMS (onset of clipping, 100mW) 0.04%
Total harmonic distortion into 16 Ohm load @ 10KHz:
1V RMS (62mW) 0.05% 1.27V RMS (onset of clipping, 100mW) 0.1%
Unconditionally stable on capacitive loads
Thursday, September 11, 2014
Stereo Headphone Amplifier
Stereo Headphone Amplifier circuit uses DC voltage source 9Volt. As the name suggests this headphone amplifier circuit has inpur stereo and output to power about 50mW at 32 Ohm load. The series of "Stereo Headphone Amplifier" It uses mini-amplifier IC NE5534. Because of this NE5534 IC didalamanya there are 2 pieces mini amplifier then simply use 1 piece of IC NE5534 to Stereo Amplifier aHeadphone this. Stereo Headphone Amplifier series has this capability and low distortion, low noise. Stereo Headphone Amplifier circuit has a strengthening of 3.5 with 3.6 Vpp at 32 Ohm load.
Component Stereo Headphone Amplifier
P1 = 22K
R1 = 18K
R2 = 68K
R3 = 68K
R4 = 68K
R5 = 18K
R6 = 68K
C1 = 4.7uF/25v
C2 = 4.7uF/25v
C3 = 22pF
C4 = 220uF/25v
C5 = 220uF/25v
C6 = 4.7uF/25v
C7 = 22pF
C8 = 220uF/25v
J1 = 3.5mm Stereo Jack
B1 = 9V Alkaline Battery
IC1 = NE5532 or NE5534
SW1 = SPST Toggle Switch
Wednesday, September 10, 2014
powerful pocket Headphone Amplifier circuit Wiring diagram
Lots of guys asked me about Pocket head phone amplifiers.This schema will be a good answer for that.Here I have used very common IC OPA134.You can power this schema with 9V battery.
Note
# Design this schema on a PCB
# use 9V to power this schema
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