Real TrainWreck mojo!

[pdf64]

It seems bizarre how on p204 he says that in the old days, people had too much pride to make copies, ie tread on the toes of other manufacturers, citing that Marshall wouldn't contemplate making a Vox copy.
Say what!
Maybe because they had their hands full ripping off the 5F6A and Dominator

[Enzo]

Amen, those early MArshalls had no similarity to a Bassman. Gosh no.

are we not a little quick to dismiss what he says as nonsense, no matter how unlikely it may sound?

After 200 plus posts on the matter, I might object to the term "quick to dismiss." As wiser men than I have said, keep an open mind, but not so open your brains fall out. We shouldn't label something as BS just because we don't understand it, but on the other hand, we should not bend over backwards trying to rationalize something that seems ludicrous.

[Justin Thomas]

While I understand that Marshall "copied" a Fender Bassman & a Watkins Dominator, I don't see it as the same level as today, when there are entire companies and factories devoted to reverse-engineering a design, making it as cheaply (both cost and materials) as possible, and then flooding every single market on Earth with those copies.

Marshall initially copied a Bassman as well as they could, but they continued to evolve instead of always ripping off what Fender did. Marshall began the same way most of us did - but also like most of us, they moved beyond copy and paste. A fairer comparison to me would be Fender vs. Ampeg, even though BOTH seemingly lost out to Marshall in the late 70s. But they each had their own ways of getting there. Mesa, Vox, Traynor, Gibson, all did what they could to ADD to what was out there, without ripping off others. Well, okay, Mesa went overboard with patenting everything...

Mark Sampson - I'll make an AC30 that doesn't break on the road... done, then he branched out. We all start somewhere, but we all try to GET somewhere else, too. At least, we USED to... sigh.

Justin

[bob p]

the great thing about those Mesa patents is that all of the good ones have already expired.

[Chuck H]

the great thing about those Mesa patents is that all of the good ones have already expired.

And all of the BEST ones were easy to defeat because of prior art, so builders went right on using them BEFORE they were expired Almost anything they patented that was their own original design wasn't worth doing.

[bob p]

Have you been keeping up with the changes to patent law, Chuck? Things changed radically in 2013 when Obama signed the America Invents Act into law. One of the odd quirks in the change from a "first to invent" system to a "first inventor to file" system is that you can now file a patent using someone else's prior art, as long as their art is less than a year old, even if you're not connected to the author's artwork or the invention of the product.

[Chuck H]

Brilliant! Edison would be ecstatic!

[Justin Thomas]

Yeah, I'm sure Mesa's Minions will be trolling all the fora now for new ideas to patent... And it'll be 15lbs of crap stuffed into a 5lb bag...

More seriously, how do we as a community protect each other from scavengers? Also, do we have to date any of our work but not share it online for a year? Do we care enough about each other to not put up any schematics of our commercial builder friends here?

Whole can of Ethic-Worms opened up with that one...

Justin

[bob p]

Everyone who deals with patents in industry was scrambling in 2011-2013 to cover all of their bases when the law changed. Everyone was scrambling to determine if they had any unpublished trade secrets that should now be patented, or any existing patents that could be re-filed. It was a crazy time.

More seriously, how do we as a community protect each other from scavengers?

That's a futile effort. This is an open forum, visible to the world, and prior art doesn't matter any more. The filing date is what matters.

Schematics? Whether or not we post a schematic has no effect on any patent. The schematic question remains unchanged: whether someone else's artwork is protected by copyright, or whether someone posts their own artwork.

[Tom Phillips]

...Everyone was scrambling to determine if they had any unpublished trade secrets that should now be patented...

Well...If they were to file a patent on it then it would no longer be a trade secret.

[Gnobuddy]

Well...If they were to file a patent on it then it would no longer be a trade secret.

Filing for a patent can be pretty expensive: The Cost of Obtaining a Patent in the US - IPWatchdog.com | Patents & Patent Law

That sort of expense may be well worth it for a large corporation, but is probably out of the question for small "boutique" manufacturers.

-Gnobuddy

[Chuck H]

Or even a mid sized manufacturer Often times, even when a product is made by a well recognized, but not large manufacturer it isn't uncommon to see "goop" inside that hides the circuits. The Suhr Badger comes to mind. Not to mention how easy it is to sway the dolts at the patent office when it comes to specific technologies. Many electric guitar amp related patents have provenance thirty or even fifty years old in some other non guitar amp, tube related design from the golden age of "valves". Like it's somehow "new" tech when applied to a different purpose amplifier that still uses tubes. Pffft... Randall has almost a dozen patents that were originally used in some "other" sort of tube amp decades earlier.

[Steve A.]

While I understand that Marshall "copied" a Fender Bassman & a Watkins Dominator, I don't see it as the same level as today, when there are entire companies and factories devoted to reverse-engineering a design, making it as cheaply (both cost and materials) as possible, and then flooding every single market on Earth with those copies...

While Behringer/Bugera had/has a reputation of blatantly stealing designs from other companies the V22 amp they have been making in various incarnations for ~5 years is really nice and seems to be an original design.*****

BTW Bugera acquired a reputation for poor quality control when they entered the guitar amp market ~10 years ago but seem to have worked those problems out.

Steve A.

***** Here are the V22 schematics if anyone wants to figure out what they are based on. (I did notice that they used a Dumblesque local feedback loop ahead of the tone stack like in the Peavey Classic 30.)
BTW my friend Felix says that the OD channel gets the sound and response of his Zendrive (only better) so I guess that would make it Dumblesque...

[bob p]

I have one of the most recent incarnations of that amp, the "Infinium" model. by any chance would you have a schematic for the infinium version? I'd like to look at the auto-bias circuit but I've had no luck in finding a schematic.

I bought the V22 as a cheap low-power living room noodling amp. It fits that role pretty well. The clean channel is nice and chimey, though I have to admit that the bass response has been designed out of the circuit. Look at all of those parallel cap/resistor combinations that are designed to high-pass filter the amp. At low volume levels the filtration is so aggressive that there's no hope of getting any bass out of the amp even with the control set to 10. The result is that the amp sounds nice and chimey. Another way to say that is that it sounds thin.

I haven't spent a lot of time playing with the gain channel. Or should I say, I spend most of my time avoiding it. In my opinion, it's just friggin' awful. On my amps if I set the gain above 1-2 the signal ends up being harshly clipped and there's no way to get anything that's remotely sweet sounding out of it, it's primarily HF hash. (Same on both amps) It's definitely designed for people who want more gain than less.

I thought about trying to do some tube swapping, inserting a lower gain triode in the gain circuit, but looking at the schematic that doesn't seem to be such a good idea -- the designers didn't bother to isolate V1 and V2 into different channels to facilitate tube swaps. The result is that you can't change one channel without changing them both. IMO that was a design oversight.

[Pedro Vecino]

At first glance and without comparing it directly with the scheme seemed to me a Classic 30 with the boost transformed to a mid-shift and a presence control added.