I found that some fans are changing the model of quad405.
Use MOSFET. Or parallel output transistors. In fact, this is not feasible.
If you are interested. You can study the quad707 model I designed.
It uses six NPN output transistors.
In addition, I need to add. I don't produce them.
Or sell them. Because it was made in 2012. It has a history of ten years.
But I have never sold them. Because I don't feel satisfied with it.
If anyone is interested. They can be produced and tested. We can communicate with each other
You can download PCB documents. Direct production.
Use MOSFET. Or parallel output transistors. In fact, this is not feasible.
If you are interested. You can study the quad707 model I designed.
It uses six NPN output transistors.
In addition, I need to add. I don't produce them.
Or sell them. Because it was made in 2012. It has a history of ten years.
But I have never sold them. Because I don't feel satisfied with it.
If anyone is interested. They can be produced and tested. We can communicate with each other
You can download PCB documents. Direct production.
Attachments
If the diagram is respected, it is interesting.
certainly one of the best bass I've heard in my life.
certainly one of the best bass I've heard in my life.
Insofar as it is found everywhere on the net, not sure that it still has a great importance.
By the way, that's a very good question, where can we find out if it's copyright or left ?
By the way, that's a very good question, where can we find out if it's copyright or left ?
I've never seen a copyright notice in any Quad manual since the year dot, but that doesn't mean they aren't copyright: they are by default. But they don't seem to care, judging by all the copies out there, so arguably they have let them all lapse into the public domain.
They had their 21 years of patent protection, that would have done them far more good.
They had their 21 years of patent protection, that would have done them far more good.
I'd be interested if you have Gerber files available for this board. Is anyone else interested as it might be worth getting some made by JLCPCB.....
Copyright is valid for 75 years.
But it can be fought if it is a generic circuit, with modifications.
Say a 5200/1943 circuit or a 3055/2955 circuit with different capacitor values...those cannot be patented or copyrighted.
I do not think an audio amplifier circuit using generic components can be patented.
And I do not think Quad was a big player worldwide, more a boutique brand.
But it can be fought if it is a generic circuit, with modifications.
Say a 5200/1943 circuit or a 3055/2955 circuit with different capacitor values...those cannot be patented or copyrighted.
I do not think an audio amplifier circuit using generic components can be patented.
And I do not think Quad was a big player worldwide, more a boutique brand.
https://www.hifispeaker.wiki/item/quad-707
1997, and a bog standard MJ15003 output stage.
Im Possible to protect (in two words)...
1997, and a bog standard MJ15003 output stage.
Im Possible to protect (in two words)...
There is a huge difference between copyright and a patent. If you make a drawing, that is then copyrighted to you and nobody may reproduce it without your consent. Funny enough, I can make a hand drawn copy of your drawing (illegal) and then this becomes MY copyright.
Copyrights are very difficult to enforce.
But at one time, Amazon refused to print a book for me because I could not prove there was no copyright, although I even searched the Library of Congress (US) copyright register, and it was not there. The book was from 1950 or so.
I could also proof that one of the authors was deceased (I found his obituary) but no trace of the other author, so no proof.
Lulu had no problems with it and basically said, it's your responsibility.
Jan
For 75 years after the author's death. But copyright only applies to the expression of an idea, not the idea itself. So it applies to a specific drawing of a circuit, but not the circuit itself. To protect the circuit you have to patent it.
| I do not think an audio amplifier circuit using generic components can be patented.
You are mistaken. McIntosh, Quad, and many others have patented circuits based on original ideas.
As a matter of fact Quad provided circuit schematics in their user manuals for many years, but they also had plenty of patents, so presumably they didn't care about the schematics: or wanted anyone to be able to repair their products.
Intel copyrights their chips, some are difficult to patent.
And if the circuit is from a modified application note circuit, most lawyers would not bother to litigate.
The fine point of law that the circuit was made public for the purpose of service / repairs, and not for manufacturing copies will be interesting for lawyers to argue.
In either case, the expense of proving the originality of work for a 25 year old drawing, and the resulting financial loss by illegal manufacture of copies will be expensive for the plaintiff, as at least here the plaintiff must deposit about 25% of the claimed amount when filing the suit, and about 10% will go in fees.
So the person who feels aggrieved has to spend 35%, and after 5 - 7 years, accept what the court decides, or appeal.
That can run 40 years, and no interest is paid for the duration.
The duration of copyright and patents varies from country to country, and its automatic nature also.
I have seen copyright by author, renewed by publisher, and finally free...Sherlock Holmes and P G Wodehouse.
And if the circuit is from a modified application note circuit, most lawyers would not bother to litigate.
The fine point of law that the circuit was made public for the purpose of service / repairs, and not for manufacturing copies will be interesting for lawyers to argue.
In either case, the expense of proving the originality of work for a 25 year old drawing, and the resulting financial loss by illegal manufacture of copies will be expensive for the plaintiff, as at least here the plaintiff must deposit about 25% of the claimed amount when filing the suit, and about 10% will go in fees.
So the person who feels aggrieved has to spend 35%, and after 5 - 7 years, accept what the court decides, or appeal.
That can run 40 years, and no interest is paid for the duration.
The duration of copyright and patents varies from country to country, and its automatic nature also.
I have seen copyright by author, renewed by publisher, and finally free...Sherlock Holmes and P G Wodehouse.
Sorry Naresh, but most of that post is in error.
Copyright & patent is a complex field, not at all 'this makes sense'.
Been there, done that.
Jan
Copyright & patent is a complex field, not at all 'this makes sense'.
Been there, done that.
Jan
No it isn't. It is a current-dumping output stage, and it was patented by Quad in about 1974. That patent had certainly run out by 1997, but the technology was certainly not 'impossible to protect'.
Agreed, it is a complex field, and rules and reactions vary from country to country.
Bear in mind that the original thread starter is a vendor also, and he may be seeing our reaction.
The topic was whether the Quad circuit is worth copying or not...and if it is being modified by some people.
Bear in mind that the original thread starter is a vendor also, and he may be seeing our reaction.
The topic was whether the Quad circuit is worth copying or not...and if it is being modified by some people.
I hope he is. He seemed to be claiming to have designed the 707, which he certainly did not.