[sdiy] Legal issues of cloning

[Magnus Danielson]

Hi,

On 10/06/2013 12:18 PM, Richard Wentk wrote:
> I think Tom covered it. Adding extra features won't protect you from legal action, because key circuit features and techniques are patented, and your new features won't change that.
>
> But most vintage patents have expired now, and the lack of legal action suggests the big names don't really care about chasing down imitators. If nothing else it would be bad PR.
I expect there to be very few analogue design patents which is still
valid, meaning that they are not covered by patent. This is the trade
you do, you give up technical information on a design principle for a
limited monopoly right for making money in the market. When the limited
monopoly is gone, everyone can use it freely and moves the industry
knowledge forward. Do read the patents, as they are meant to be read and
applied.
> In any case, most new designs use modern components. So the schematics aren't identical. And it's difficult to argue that - say - a VCA or a gain cell is a rights infringement.
The different details of the schematic does not suffice to keep a design
from being an infrigment. That's why patents can be enforced when the
basic principle is as being described in the patent. Roland had to
change their filter for instance.
> I don't know what the situation is with the 2600 clone. I think technically Gibson owns the rights via Rhodes, who bought ARP. But the patents have expired, and I doubt there's anything actionable in a modern version of the schems.
>
> It's interesting just how little legal action has happened in this area. Apparently it's enough to say your modular filter is *based on* the CS-80/etc and/or to give it a silly name, and the big co's lose interest.
Even openly advertised and actively sold as such from large active
vendors works without retribution. Thing is, if it is sufficiently back
in the history, being cloned like that is really just free PR and no
significant loss of income.

The design itself is protected, as they have copyright to schematics and
layouts. This copyright is possible to avoid by not doing a direct copy.
Same circuit, but different schematics and layouts, no apparent
infrigment on trademarks and you should be safe. Reference to the
trademarks seems to work most of the time, but it's not necessary safe.

Cheers,
Magnus