After several requests of the correspondents, the decision to design a headphone amplifier 9V power was finally taken. The main requirement was to feed the circuit by a common, PP3 (transistor radio) alkaline batteries. Therefore, the circuit implementation of a low current draw was absolutely necessary, while retaining high quality.
The emergence of low-noise 5534 operational amplifier at a reasonable price was much appreciated by audio designers. Now it is difficult or impossible to design a specific phase that has the performance of 5534, without the complexity unacceptable. 5534 operational amplifiers are available from various sources, in a conventional 8-pin dil format. This version is internally compensated for gains of three or more, but requires a small external capacitor (5-15pF) for unity gain stability. The 5532 is a convenient pack of two 5534s in an 8-pin device with internal unity gain compensation, since there are no spare pins.
The 5534 / 2 is a low distortion and low noise device also has the ability of low-impedance load to full voltage swing, while maintaining low distortion. It is fully output short-circuit. Therefore, this circuit is carried out with a single 5532 chip forming a pair of stereo amplifiers, invest, have a current gain of about 3.5 alternating and capable of delivering up to 3.6 V peak to peak 32 Ohm load (corresponding to 50mW RMS) less than 0.025% total harmonic distortion (1 kHz and 10 kHz).
Considering that the average current drawing a power of 15 mW per channel is about 12-13mA (both channels driven), this headphone amplifier will become a "must" for many DIY enthusiasts who need a device High quality, high performance laptop.
