Low distortion Class-B circuitry 6V Battery Supply
Some enthusiasts of High Fidelity headphone listening want the utilization of battery energyed headphone amplifiers, not just for transportable gadgets but additionally for home \"table\" softwares. This design is intended to fulfil their needs and its topology is derived from the Portable Headphone Amplifier that contains an NPN/PNP compound pair emitter follower output stage. An superior output using functionality is achieveed via making this a push-pull Class-B association. Output energy can reach one hundredmW RMS into a 16 Ohm load at 6V supply with low standing and mean present consumption, allowing lengthy battery duration. The single voltage gain stage permits the easy implementation of a shunt-feedback circuitry giving superb frequency steadiness.
Circuit diagram :Battery-powered Headphone Amplifier Circuit diagram
- For a Stereo model of this circuit, all parts should be doubled aside from P1, SW1, J2 and B1.
- Before setting quiescent current rotate the volume regulate P1 to the minimum, Trimmer R6 to most resistance and Trimmer R3 to in regards to the middle of its shuttle.
- Connect an acceptable headphone set or, better, a 33 Ohm 1/2W resistor to the amplifier output.
- Switch on the provision and measure the battery voltage with a Multimeter set to about 10Vdc fsd.
- Connect the Multimeter throughout the positive end of C4 and the poor floor.
- Rotate R3 with a view to learn on the Multimeter show precisely half of of the battery voltage in the past measured.
- Switch off the availability, disconnect the Multimeter and reconnect it, set to measure about 10mA fsd, in sequence to the certain supply of the amplifier.
- Switch on the provide and rotate R6 slowly except a studying of about 3mA is displayed.
- Check once more the voltage on the positive finish of C4 and learnjust R3 if essential.
- Wait about quarter-hour, watch if the present is various and readjust if important.
- Those fortunate sufficient to achieve an oscilloscope and a 1KHz sine wave generator, can power the amplifier to the utmost output power and alter R3 with a goal to get hold of a symmetrical clipping of the sine wave showed.
Technical data:
Output power (1KHz sinewave):
16 Ohm: 100mW RMS
32 Ohm: 60mW RMS
sixty four Ohm: 35mW RMS
100 Ohm: 22.5mW RMS
300 Ohm: eight.5mW RMS
Sensitivity:
160mV enter 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) zero.015% 1.27V RMS (onset of clipping, a hundredmW) 0.04%
Total harmonic distortion into 16 Ohm load @ 10KHz:
1V RMS (62mW) 0.05% 1.27V RMS (onset of clipping, one hundredmW) 0.1%
Unconditionally secure on capacitive loads
16 Ohm: 100mW RMS
32 Ohm: 60mW RMS
sixty four Ohm: 35mW RMS
100 Ohm: 22.5mW RMS
300 Ohm: eight.5mW RMS
Sensitivity:
160mV enter 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) zero.015% 1.27V RMS (onset of clipping, a hundredmW) 0.04%
Total harmonic distortion into 16 Ohm load @ 10KHz:
1V RMS (62mW) 0.05% 1.27V RMS (onset of clipping, one hundredmW) 0.1%
Unconditionally secure on capacitive loads
Source : red circuits
