Thursday, March 1, 2012

Class A Headphone Amplifier

The headphone firm was a simple routine to design. This is due to the fact that neither the fill features nor the strength demands in the result is very difficult to obtain because the earphones are generally having a 50 ohm and higher fill impedance up to 600 ohms. For the regular result, it will only require 1 V to 2 V RMS at highest possible. A category A level of firm is recommended because only low strength is necessary on this routine. Frequently, category A amps include a continuous present transistor linked from result to adverse strength and a pushed transistor linked from result to good strength. The continuous prejudice present runs immediately from the good provide to the adverse provide in the lack of feedback indication. This will result with no result present but with several capabilities absorbed.

In this routine, the transistors Q5 and Q6 should be ranked at 100 mA each, to be able to work as category A firm properly. A strength result of 1.5 H is created from the 15 V strength. A small heatsink is necessary though for each transistor. The sound feedback indication is specific by a 10K ohm logarithmic potentiometer RV1 while the result DC balanced out current for 0 V is specific by the slimmer TR1. Two tour will be required however, if it is suitable for music program.

                                                                                    Component List :
R1-4= 1.2Kohm
R2-3= 3.9Kohm
R6-10= 10Kohm
R7-9= 2.2Kohm
R8= 150 ohm
R11-13= 6R8 ohm
R12= 4.7 ohm R14=68Kohm
RV1= 10Kohm Log. pot.
TR1= 10Kohm Trimmer

C1= 4.7uF 63V MKT
C2-7= 100uF 25V
C3-5= 100nF 100V MKT
C4-6= 100uF 16V
C8-10= 470uF 25V
C9-11= 100nF 100V ceramic
Q1-3= BC184
Q2-4= BC214
Q5= BD136 or BD538
Q6= BD135 or BD537
All resistors are 1/4W 1%

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