You can use a higher- voltage supply and run it into a LP2950 LDO (low drop-out) 3-terminal regulator to tame the output ripple/noise. The +5VDC out will be more than quiet enough for the Velleman kit your building. I wouldn't worry about damaging the two MICs as they are more than likely rated for 2-10v operation as Velleman designers wouldn't want a pile of returns with burned-out ECMs to deal with. I'ts a nice little circuit that can easily be reduced in size by re-designing the PCB for SMD components. It would look like a credit card.