amplifier - How to amplify both phone audio channels in this case (infrared remote)

I'm a photographer and have limited knowledge about electronics. recently I saw this circuit: which is explained here I tried to Build it, it works fine on my laptop jack, but does not work on my android smartphone jack. I guess it's because of low output signal voltage (less than 0.6V) as explained in this case. since I only have lm386 IC in my stuff an it's important to keep circuit size as small as possible, I am wondering if there is a way to use just one lm386 IC to amplify both channels without any change in output infrared signals? please guide me how to design my circuit.(with one or two ICs) Thanks

Answer

All you need to do is have a simple "bias" on the base of the transistors in your circuit. This would basically "pull them up" to have a higher average value; say 0.5 volts, and a capacitor to couple with the bias. So when the alternating waveform from one of your jacks goes say between +/-0.6v, the transistor would see +1.1 to -0.1v. The circuit would look like this:

^{simulate this circuit – Schematic created using CircuitLab}