So it seems that that part includes a reverse-polarized diode to ground. This will effectively chop off (most of) the negative half-wave of the signal (though not sure what the forward voltage of the diode is, so it may even fail to protect your analog input). If you are using it for something like envelope detection, it may be enough, but if you are looking to use the signal for audio purposes, you are probably better off using the original circuit. To improve the reliability of the build, don't use a breadboard, but use veroboard or stripboard instead.