I've used this one, but availability can depend on your location:I'm having issues finding the inductor, plans call for a .9 mH 18 awg wire.
Can someone share a link or part number?
Jantzen Audio, 0,900 mH, 17 AWG (D 1,2 mm). Two different spool sizes: 000-1413 (OD 45, ID 25, H 30 mm), or 000-1566 (OD 52, ID 20, H20 mm).