Patent No 611961

[Ears]

I posted elsewhere in forum that Guytron patented an idea in 2000 that I (and probably many others) had had many years earlier. Fred Nachbaur also uses the idea in his Dogzilla amp, namely to miniaturise a power amp section complete with OPT and then re-amplify the attenuated output.
I searched publicly accessable websites to legally locate the patent details which are supplied in attachment.

I'm interested in any comment on this patent's 20 claims given on pgs 13-15 of the document.

They seem over reaching to me.

[John_P_WI]

Ears,

There is nothing new with this, in fact, I remember discussing this exact thing with John Mc Intyre back in '93 or so. The one thing that I noticed is that the claims are very broad and seem to apply to a "systems" approach. In my brief scan of the patent, it appears that a resistive dummy load is used, not a reactive (hint) that would allow for simulated speaker reactance and back emf.....

The patent can easily be prototyped using a reverb transformer and resistive network.

John

[Ears]

Ears,

There is nothing new with this, in fact, I remember discussing this exact thing with John Mc Intyre back in '93 or so. The one thing that I noticed is that the claims are very broad and seem to apply to a "systems" approach. In my brief scan of the patent, it appears that a resistive dummy load is used, not a reactive (hint) that would allow for simulated speaker reactance and back emf.....

The patent can easily be prototyped using a reverb transformer and resistive network.

John

Thanks, I thought the use of a second winding on the secondary of TR2 as means of tapping the signal was a good idea, and hadn't considered that method myself. Aiken provides RLC networks for speaker simulation in his forum, if the load, R43, in the Guytron cct was replaced by such a network I assume that the way the amplifier reacts to such a reactive load would still be sensed by this second winding.

[drz400]

Ears,

There is nothing new with this, in fact, I remember discussing this exact thing with John Mc Intyre back in '93 or so. The one thing that I noticed is that the claims are very broad and seem to apply to a "systems" approach. In my brief scan of the patent, it appears that a resistive dummy load is used, not a reactive (hint) that would allow for simulated speaker reactance and back emf.....

The patent can easily be prototyped using a reverb transformer and resistive network.

John

Thanks, I thought the use of a second winding on the secondary of TR2 as means of tapping the signal was a good idea, and hadn't considered that method myself. Aiken provides RLC networks for speaker simulation in his forum, if the load, R43, in the Guytron cct was replaced by such a network I assume that the way the amplifier reacts to such a reactive load would still be sensed by this second winding.

His patent is based on an idea people have been doing for a zillion years. In the early 80's I ran my Boogie into a load resistor so I could feed it into a complete system with effects. In fact I even bought the load resistor from Boogie who had them in stock since everyone was doing it, the Boogie had a slave out on the amp. Harry Kolbe also had a "Silent Speaker" which was a reactive load, EVERYONE and their mother was doing this including EVH. The only thing I can see as a patent is that he puts it into one amp. Personally I think that amp sounds too squishy anyway. The key is who wants to cough up the money to challenge him, what are Patents... 7 years? 14? something like that?

[dartanion]

No one would really have to directly challenge his patent. It is patent holder's responsibility to protect their IP. He would have to go after those he suspected of infringement. Besides, it would be pretty darn easy to show prior art that would invalidate his patent.

[drz400]

No one would really have to directly challenge his patent. It is patent holder's responsibility to protect their IP. He would have to go after those he suspected of infringement. Besides, it would be pretty darn easy to show prior art that would invalidate his patent.

He could sue you and that alone would cost money.
Without being a lawyer and wiothout reading through the 15 pages of mumbo jumbo.... is it stated that his "original concept" has to do with all these mechanics being in one box? If so is that grounds for a patent? Certainly it has been done many times before, even remember the Roctron Juice Extractor, that is what that whol thing was designed to do and it had EQ as well designed to load an amp, take a signal that gets EQ'd some more and sent to a power amp.

But as far as putting everything in one amp Guytron might be the first.
Hardly grounds for a patent you would think.

[John_P_WI]

Regardless of the patent contents, I appreciate Ears for posting this. New ideas are sparked from technical discussions which we can all benifit from. Who knows what idea could be next?

Peace, John

[VacuumVoodoo]

He had to put something "innovative" in and the only thing that barely qualifies is the double secondary winding on the intermediate OT. It works but not at all differently than putting that potentiometer parallel with the dummy load. Waste of copper IMO. Perhaps this patent covering general amp architecture is aimed at annoying Randall?

[Ears]

He had to put something "innovative" in and the only thing that barely qualifies is the double secondary winding on the intermediate OT. It works but not at all differently than putting that potentiometer parallel with the dummy load. Waste of copper IMO. Perhaps this patent covering general amp architecture is aimed at annoying Randall?

Ha Ha!

Perhaps the salient point to me is - Has this idea REALLY been exploited fully? It's one thing to use dummy-loads and speaker simulators on existing power amps, its another to use power scaling approach to existing output stages, yet another to build much lower power amps (see nano amp http://zvexamps.com/amp_view.html by zamps) and tube stomp-boxes (check out stage hog http://www.stephensonamps.com/stagehog.htm by stephenson amps).

Has anyone seriously integrated a really low power power section (less than a watt), with a properly modeled load, INTO a standard amp?

If not, why not? Who has done it?

What are the inherent problems associated with such a scheme?

It seems the obvious route if power amp behaviour at any volume is the desired goal.

[VacuumVoodoo]

[
Has anyone seriously integrated a really low power power section (less than a watt), with a properly modeled load, INTO a standard amp?

Tommy Folkesson (website in swedish only) here in Sweden has been implanting this scheme in Fenders, Marshalls and other amps for some years now.

IIRC Garnet in Canada did the same thing even before this patent application was submitted in 1997.

It is also possible to pick the signal off reverb transformers secondary with reverb driver coil providing proper speaker like load. Much simpler and you won't need a dedicated transformer. Heck, this isn't claimed in the aforementioned patent so if anyone tries to patent this I hereby claim priority.

[John_P_WI]

It is also possible to pick the signal off reverb transformers secondary with reverb driver coil providing proper speaker like load. Much simpler and you won't need a dedicated transformer. Heck, this isn't claimed in the aforementioned patent so if anyone tries to patent this I hereby claim priority.

Hi Aleks, I claim it! See the second post.

Through all of this I can't get the horrid sound of Marshalls valvestate SS output out of my mind. Guess I'll have to self prescribe some high db EL34 "tone shaping / mind bending".

Peace, John

[VacuumVoodoo]

Ok, we'll split all those royalty millions.

[BobW]

Plant patents, such as this, are good for the initial 3 years, then a fee is required to keep it current. The big problem with patens today is that anyone, including me, can write an abstract into an acceptable format, make broad claims, and have it patented. It seems no one at the patent office is challenging claims, and not that it should make a big difference, but I doubt the examiner's primary language is English based on his name alone. The patent office is there one one primary reason, to make a profit.