[sdiy] Legal issues of cloning

[GGG]

Dear collegues,
	There are lot of classical synth clones arround, available as DIY
kits - I've built TR909, Polivoks VCF, CS-80 VCF, there are active
discussions on ARP 2600 clone KIT, about to be on sale.
	I wonder, what are the legal issues of cloning synths? What's a
procedure of getting permission (I doubt, it's easy to get a permissoin from
producers , like Korg or Yamaha, just because of hudge scale of companies
and beurocracy and Polivoks is dead end at all). If a developer of the clone
adds some sigificant upgrades to the original schematics - is this still
considered as a direct clone, or what's a degree of upgrades, one should
add?

Best regards,

Girts