@davideo
No problem, glad it's been of some use to you :-)
@countzero
Many hobby electronics stores don't stock much in the way of SMD components. Mainly because most hobby electronics involves leaded components, which are easier to use with veroboard or whatever.
The capacitor voltage rating is good advice. In the case of the Amiga audio circuit, you can also get away with a higher value of capacitance since all the electrolytics are either used for power supply decoupling, or AC coupling/DC blocking.
For example, the reactance of a 22µF capacitor used for audio coupling at 100Hz, Xc = 1/(2 x pi x f x c) = 72 ohms
If you replace it with a 47µF capacitor:
Xc = 1/(2 x pi x f x c) = 33 ohms
Which results in a lower cutoff frequency, i.e audio bandwidth is increased.
In any case, the circuit performace would be *slightly* better at lower frequencies (not that the Amiga's DAC can really do much better), but larger capacitors have a larger physical size, so you'll eventually start running into mechanical problems.
If capacitors of a smaller capacity are used, the lower cutoff frequency of the circuit will increase (reducing audio bandwidth). In the case of decoupling, the circuit may suffer excess noise if smaller value capacitors are used.
