Lets say I take a pedal currently in production, draw a schematic from the traces (all my own work) and post it along with my tips for modifying the pedal. My mods would be ok to post but not the schematic, right?
I am not a lawyer. (IANAL)
Just wanted to say that - but here's the scoop:
1. Schematics themselves are not protected by copyright law. The devices they represent may be patented, or contain elements protected by patent law however.
2. A *DRAWING* of a schematic may be protected by copyright law, as a work of art (like a painting or a photograph.)
3. A PCB layout may be similarly protected
4. The "trade dress" and appearance of a pedal or device, including but not limited to physical design, graphics, fonts, and logos may be protected by copyright law. In addition, the physical design of a device may be protected by a "design patent" (a special type of patent.)
So to answer your question:
If you draw a schematic, it can be protected by copyright law
If you make a PCB layout, it can be similarly protected
If you devise modifications to a pedal, the document detailing those mods may be protected.
All of these things are your creation and may be posted or distributed in any way you (the original author of those works) sees fit. Only the original author or his / her designated agents may post them while they are under proection of copyright law. If unauthorized persons distribute them or attempt to modify or plaigarize, you may have some legal recourse.
Whether you want to go to the trouble of *FILING* copyright paperwork, or obtaining trademarks or patents is up to you. I am not a lawyer, but my wife's firm handles Intellectual Property law for a number of well-known corporations, and I would be happy to refer any "forumites" (people who use a forum) to a qualified attorney who can advise better. This is just what they told ME when I started my business.

Matt Farrow