Bypassing screen grid resistors???

[Alan0354]

Then again, Mesa seems to patent items that are not at all earth shattering.

More 'bells & whistles'.
Yawn.

Good lawyers!!

I can tell you, it's all about the writing on top of the invention. My first pass got rejected out right. I studied the book harder, rewrote the claims.......WITHOUT CHANGING ANY COMPONENT, WIRING OR ANYTHING of the design!!! They accepted in out right and passed!!!! It's not only the idea, it's how good you write according to their specific requirements. Nothing change since the get go, just difference in writing the claims!!!!

If you really have something, you want to broaden the scope to cover all cases so people cannot find loophole that easily to steal your idea to make money. Look at the noise cancellation patent of Leo Fender and Gimpel of Musicman. They never once mentioned "Guitar' in their claims. We use "electric stringed instruments" to cover all cases. But if you don't have an idea, you want to patent in a very limited scope.....Guitar........"overdrive". Those are very specific terms that limit the scope of the patent coverage, but at the same time make you unique. I think he want to have a patent to get the fame, not even to prevent others from copying it.

[J M Fahey]

Anybody inventing something and dreaming on getting a patent should read this first:
http://www.tinaja.com/glib/casagpat.pdf

Anybody trying to avoid Lawyers $$$$ and do it themselves should be aware of:
http://www.tinaja.com/glib/bustpat.pdf

Some patent horror stories:
http://www.tinaja.com/glib/patnthor.pdf

Yet, still there's some hope, just *IF* :
http://www.tinaja.com/glib/when2pat.pdf

although all his advice can be condensed in:
"forget patents, just start *using* the idea, make as much money as you can before others copy it and when they do, go home watch TV, don't even *try* to sue"

[Alan0354]

patenting is one thing, enforce is another thing. Nobody is going to enforce your patent, it's up to you to sue the offender.

Also, you really have to study how to write a patent, it is not simple to write the claim language. Take me half a year of studying to write one and half pages of the claim. You can get a patent with very specific language and people can bypass your patent easily and you have a hell of a time to enforce the patent. It's all about how much effort you put in writing the patent if you write your own.

Also, people should have a realistic view of a patent. Most patent does not make money, might not even make the money for the patent. It's more about achievement, that you have your name down in the history as they last forever. You can still find patents that were written over 100 years ago. The enforcement period only last 20 years max, but your name will be on the patent forever. That's why people spend so much time research and publishing in the scientific journal, not to get money, but recognition from their peers. Once every so often, someone gets lucky and make big money out of a patent. But that's not the norm.

I bet Randell Smith never have intention to enforce nor can he really enforce as you can change a little bit and bypass the patent. But he get his name recognition down in the books. Also, in engineering and scientific world, people look at what you achieved.

To me, it's a hobby, an achievement. The other two noise cancellation patent did not make a lot of money. I have no illusion this will be any different. It's more about I did it.

[NateS]

I don't know how many people they've sued, but Randall does keep a pretty good stash of stationary on hand for sabre rattling. In this business few people are big enough to be able to afford even showing up in court.

[Chuck H]

I think I heard of Mesa going after an "infringer" once. And I think they dropped it before it went to court through some agreement. Most, if not all the patents currently held by Mesa can be too easily proved as having existed before the patent. In most cases circuits so common that the notion of using them in guitar amps doesn't even make them novel. I really believe they secure these patents as a matter of discouragement rather than protection.

[Alan0354]

It is about money. If he has money and not willing to let it go, then he can pay to sue.

Also, whether you can defend your patent has a lot to do with how popular and how much demand of your invention. If you find someone using your patent and make millions and millions, you bet there will be law film lining up to take your case pro-bono. Again, it's all about money and money talk...........You either have a lot of money to sue, or you have such a money making product that attorney are willing to take pro-bono.

[Alan0354]

I think I heard of Mesa going after an "infringer" once. And I think they dropped it before it went to court through some agreement. Most, if not all the patents currently held by Mesa can be too easily proved as having existed before the patent. In most cases circuits so common that the notion of using them in guitar amps doesn't even make them novel. I really believe they secure these patents as a matter of discouragement rather than protection.

Yep. I looked at the 20 20 schematic, I can't spot anything unique. Some ideas are so good you can spot it out right.

Ha ha, when this patent thing came up, I immediately thought about your advice to lower the coupling cap between stages in the cascade amp in my thread. Someone can actually wrote a stupid patent and might actually get it!!! Of cause if you write "stop farting with high pass filter to eliminate the low frequencies", you'll be rejected out right.

But what if you write "A method of increase the Intermodulation frequency component desirable for overdrive sound of a guitar amp and suppress the undesirable low intermodulation frequencies". You might have a better chance to patent the small value cap for coupling and bypassing of the cathode.Then you throw a bunch of technical jargon about IMD!!!

It is all about how good your lawyer writing the claims...........or how much effort you are willing to learn how to write the claims.

[Alan0354]

Some of you guys are very knowledgeable and have good ideas. Don't discount that it's "understood", "no big deal", or "someone must have it already". You never know until you try. Yes if you get a lawyer, it's going to be a lot of money. But you can learn how to write a patent yourself.

Yes, you might make mistake, you might write something that easily bypassed by someone. BUT if you don't do it, you definitely will not get any right.

Yes, it takes a lot of effort. I spent two to three hours, studying the book, writing out the claims to practice, learning how to do patent drawing. All stumbling along. Takes patience to do patent search...........And the worst part is finding a patent that cover your invention. I designed what Leo Fender did, then I start from scratch, and design the second one that turn out to be the same as Gimpel of Musicman. Took me the third try to get one.

Then after submitting the application, all the info in the book of patent were mostly wrong. Then I had to stumble with the USPTO. BUT the most important thing is.........After I did the first one, the second one is going to be a lot easier as the process is the same.

Don't think "Oh the lawyer know better how to write it, I can't do it". A lawyer is a human also, he/she has to learn from ground scratch. If you start telling you that you can't do it, you will never do it. What make you think they are better than you? At least, write the best you can and get a cheaper lawyer to just look it over and give you some pointers. Nothing is too hard.

[Gingertube]

No-one seems to have mentioned the grid stop function of the screen grid resistor.
The screen is just another grid, there is gain from a signal applied to the screen. Sometimes (particularly with Ultralinear connection) a screen grid resistor is required for stability. Any screen grid resistor should be wired with the resistor body hard up against the tube socket screen grid pin, just like you would for a grid 1 grid stop resistor.

Otherwise the screen grid resistor is there to limit screen grid dissipation, bypassing it with a cap would negate the protection.

Cheers,
Ian

[Chuck H]

I never looked at the screen as having "gain". I always figured it just needed a stable relationship relative to the control grid and plate to allow electrons to flow. Perhaps this is why I've never understood the potential for over dissipating screen grids very well with the exception of overly high voltage. I'm still not clear on it, but your post has given me new things to consider.