Battery-less LED Footswitch Mod for the 2-Channel

[László]

I have a question about this whole process that is "legal" in nature. It is no way intended to cause problems, and please do not interpret it as such. But, it is such an obvious question (to me) that I have to post it in this forum. And furthermore, if I'm not mistaken, Les as an attorney who specializes in music production so he might have some answers already in his back pocket.

Here we go.

With regard to Mark's (EM7's) mod, as described in this forum (and on the VR forum as well)....can he "patent and/or copyright" his scematic design and method of solving this "LED problem"? And, if so, would that prevent other companies (such as PRS) from being able to offer the exact same or similar mod/option on future amp footswitches without a "royalty relationship" of some sort?

I don't want to get into the pros and cons of copyright/patent law as it pertains to this mod. I was just very curious as to whether this mod is eligible for patent protection, and if doing so would prevent other amp designers from utilizing a similiarly designed "non-battery powered LED footswitch" without providing Mark with royalties.

Bennett, while I'm experienced in copyright and trademark law, I have no experience in patent law. In principle the two are related by the "Patent and Copyright Clause" of the US Constitution, which recognized these concepts in the original Constitution (not an amendment) in 1787. Article I, Section 8, Clause 8 of the United States Constitution empowers the United States Congress:

"To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries."

Just as a songwriter has exclusive right to do certain things with his/her work, so does an inventor. If Mark's footswitch is patentable, he certainly has certain exclusive rights.
I don't know to what degree making the schematics and photographs public affects the exclusivity of the rights.

Several companies have had powered LEDs on their amp footswitches. How these work would be researched, and most patent attorneys are also engineers. I'm simply not qualified to have a clue as to whether Mark's is original and patentable. I stick to the easy stuff...mostly recording and composing music!

 

[Em7]

The control circuit, when viewed as a whole, is definitely original. To the best of my knowledge, one will not find it on any commercially produced guitar amp schematic. Most channel switching circuits that provide power to LEDs in a footswitch use bi-polar junction transistor driven LDRs to provide signal path switching. Randall Smith pioneered LDR-based channel switching with the Mark IIC. Mesa used relay-based channel switching on the Mark IIA and the Mark IIB, but that switching circuit has a major design flaw. Randall Smith wired the LED circuit between the relay coil V- connection and ground. The sleeve is wired to ground, and the tip is wired to the V- connection on the relay coil. With the switch contacts closed, the V- connection on the relay coil is connected to ground. With the switch contacts open, the led and the current limiting resistor are wired in series with the relay between V+ and ground. The LED imposes a voltage drop that reduces the voltage available to the relay coil. The current-limiting resistor combines with the relay coil resistance, which, in turn, prevents the coil from reaching the energy level necessary to build a magnetic field strong enough to close the contacts on the relay (this circuit is the origin of RED=RHYTHM). This circuit had poor switching reliability. The Mesa Boogie relay control circuit is shown at the bottom of the following schematic:

The LED current limiting resistor is the key to stability in my design because it serves as the gate discharge path when the control voltage is removed from the gate. The small charge on the gate is quickly dissipated to ground, placing the drain-to-source path in a high-impedance state. With the drain-to-source path in a high-impedance state, the connection between the V- connection on the relay coil and the supply V- connection is effectively an open circuit. The snubber diode that is wired across the V+ and V- contacts of the relay dissipates the back EMF that is created when the magnetic field in the relay coil collapses. As I mentioned above, piggybacking the indicator LED on the control voltage is the non-obvious part of the design. You will not find that part of the circuit in any amp textbook.

One last thing: Les is correct. Patent attorneys are engineers and scientists who have attended law school and passed the bar exam and the patent bar exam. Patent law is one of the few areas of law that requires attorneys to possess specialized domain knowledge outside of law. The U.S. Patent and Trademark Office also allows engineers and scientists who have passed the patent bar to practice patent law. These people are known as patent agents. Patents agents can file and defend patents. However, patent agents are not allowed to render legal opinions. It's somewhat like the British solicitor/barrister model. It's probably the only part of our English Common Law-based legal system that retains two classes of legal representation. Like the PA/MD relationship that we find in medicine today, many patent agents work with patent attorneys. I have considered preparing for the patent bar exam on several occasions, which is why I know about this stuff.

 

[László]

I have considered preparing for the patent bar exam on several occasions, which is why I know about this stuff.

You should do it if you have interest the law, Mark.

You certainly have the ability to communicate your thinking clearly, you write very well, you're obviously very bright, and you are even-tempered in your approach to a problem. I have a friend who does patent work, and it's a wonderful career. He loves it.

I enjoyed my law practice for a long time, but had other goals I wanted to pursue, which is why I got into music. I always kid around and say I was a round peg in a square hole, but I got a lot of satisfaction out of the practice for quite a few years.

 

[docbennett]

Reading Mark's posts, and experiencing his incredible breadth of knowledge....as well as his ability to use it to develop new technology....was the sole purpose behind my post regarding patent protection.
I would hate to see anyone benefit from Mark's creativity and knowledge other than Mark.
I am somewhat familiar with the patent process, having attempted to pursue a medical patent in the late '90's. Mark...from the tiny bit I know, and from what I've seen...you would probably be a fantastic patent agent in the field of electronics....specifically amp design and your area of expertise.

Is this a career that individuals can aspire towards...or is being a patent agent the "side effect" of working in related areas? In other words, can someone actually make a career out of having specialized knowledge and using it as a patent agent...I can envision a specialist being hired to pursue a patent on behalf of the inventor....working in collaberation with the patent attorney.

Sorry if this became a diversionary hijack...i find the topic to be extremely interesting and I find Mark's knowledge to be somewhat breathtaking...as an individual whose electrical knowledge is limited to setting up a good stereo system and using black electrical tape to join wires together

 

[Em7]

Les:

I will probably take the patent bar exam when I get closer to retirement. While I have downshifted career-wise, I am not quite ready to hang up my technical spurs.

Truth be told, my undergraduate and graduate degrees are in computer science, not electrical engineering. However, I attended college back when computer engineering did not exist as a separate program in most colleges and universities. Computer engineering was split between the electrical engineering (EE) and computer science (CS) departments. One either received a BSCS degree with a concentration in computer systems design or a BSEE degree with a concentration in digital design. The goal of this cross departmental program was to prepare students to become computer architects, digital logic designers, and system software designers for computer system manufacturers. In the mid-to-late nineties, a schism occurred between the two academic fields that originally combined to form the field of computer science (computer science used to be a branch electrical engineering on one end and a branch of theoretical mathematics on the other end). The electrical engineers in took their ball and ran. My undergraduate concentration now forms the core of the computer engineering program in most universities.

With that said, my goal in becoming a patent agent would be to help young software and digital device companies patent their ideas and defend against junk patents. Junk patents are becoming a major problem in the area of software engineering because large computer and software corporations are amassing huge patent portfolios. For example, LSI Corporation was awarded a fairly broad patent on a commonly used data structure known as a "multiply linked list" back in 2006. The LSI patent is the poster child for junk patents. It should have never been awarded by the U.S. PTO. Prior art existed for decades before LSI applied for the patent. If this patent were to be enforced, it would bring the Internet to a halt. Linked lists are the foundation of most of the software in use today.

 

[veysel]

Hope you can help lot of people Em7 and develop their knowledge in making their own unique ideas just like what you did and become a good example for those aspiring people who only just began in their careers.