[muffy1975]

HI,

i have de potted a certain audio company's discrete opamp. They ( these opmaps )  kept blowing up in their high end  summing mixer and was costing me a fortune to replace each time.

I have  de potted it and remade it.

How can i find out of their opamp is patented?

They have told me that it is and they would involve lawyers if i used it in my own designs.

Michael

[mitsos]

what company? You can do a search on google patents with their name, the owner's name if you know it, etc.. Something might come up. Or ask the guy that threatened you for a patent number. 

But I have to say, it seems odd to want to copy something that keeps "blowing up".  Is it heat buildup due to their potting material? Do your un-potted versions last longer?

[muffy1975]

It does not blow up when i've remade it without the potting.

it runs class A at 24V+.


And it sounds very amazing.

[audiomixer]

I think helping yourself to a working unit is probably not a problem, building a private DIY unit neither, but selling units with their intellectual property will be something different. posting a full schematic might also be over the line two, but I don't know for sure.

what do they want to do - get a search warrant for your place to check whether you build additional modules?


just my two cents....

- Michael

[pvision]

I think a patent implies something unique with no prior art. Would you find that in a class A discrete op-amp?

Here's an early valve opamp patented in 1946. It uses voltage rails of ± 350 Volts so be careful:
http://books.google.co.uk/books?id=dunqt1rt4sAC&pg=PA777&lpg=PA777&dq=patented+opamp&source=bl&ots=oWqNio9NZ4&sig=70UAJDEb6er4BxtXtmlNL9pkY6g&hl=en&sa=X&ei=Wp2gU7WaBubT7Aaev4HQCA&redir_esc=y#v=onepage&q=patented%20opamp&f=false

Nick Froome

[muffy1975]

Thanks guys,

i would not post schematic mainly cos it took a lot to figure out how they made these opamps.

However why pot something that is patented?? It is not a super simple circuit.

Michael

[ruairioflaherty]

I'd have to ask why you'd remake something that blows up all the time?  Is it really that awesome sounding?

[muffy1975]

It does not blow up when i've remade it without the potting.

it runs class A at 24V+.


And it sounds very amazing.

[mitsos]

what the heck are we talking about, make/model?  And since you've got us all curious, the schematic would be nice too.

[mitsos]

However why pot something that is patented?? It is not a super simple circuit.

potting is not just for hiding components.  In the case of API/etc format opamps, potted ones are MUCH more robust physically, so you are less likely to damage them by plugging/unplugging.  DIY ones with components on one side and pins on the other can be a pain to unplug if space is limited. Making them "upside-down" helps with this, but potting is safer, except if it doesn't dissipate heat well enough. 

[joaquins]

990 originally was potted with clear epoxy, because it's thermal properties weren't good (it expanded too much and cracked some components or something like that) thay changed to a more conductive thermally and with less expansion with temperature but dark, not for hiding components, but better reliability.

JS

[Gustav]

Class A 24V, high end summing mixer, keeps blowing up.

Phoenix Audio Nicerizer?

Gustav

[muffy1975]

Gustav,


you da man.

could be them! but i can't really say yet can I?

so, would the company you mentioned have their ' blow up all the time when potted  opamps '   patented?

Michael

ps, they specifically said they would involve lawyers if i shared what i found underneath the potting compound.

[ruairioflaherty]

A couple of thoughts.

- A quick search of Google's Patent section reveals nothing for Phoenix Audio.  Patenting is costly and time consuming, I'd be very very surprised if there is a new innovation in that opamp that warranted patenting.
- My understanding is that many of their products are Neve inspired, particularly the later Class A/B era Neve stuff (could be wrong), I'd be comparing what you've found to Neve 340/440 and others like that.
- My understanding (again could be wrong) is that you can copyright a layout but not a circuit
- Unless you plan on selling your clone I don't see how they could do anything to stop you.

I'm on retainer with several pro audio companies and value I.P., I'm certainly not a clone anything and everything kinda guy but one has to be practical.  I can understand companies being vocal in this era of cloning.

[Michael Tibes]

My impression is that quite often those companies are most secretive which have to hide that they actually didn't invent too much. To me there's also a big difference between proper engineering using common technical knowledge and real inventions. Also if they were having a reliable product or at least were trying to help once their product proves unreliable then you wouldn't have to reverse engineer the stuff in order to keep their products running. On top of that they're in the US, you are in GB? I guess I'm trying to say that you shouldn't be too scared. I also don't see why you couldn't publically share the experience of repeated failure of a certain device if you are not telling a lie.

Two practical things come to my mind: back in the days GML opamps used to blow up like popcorn in the studio where I worked. It turned out to be a problem with static electricity, the housing wasn't grounded in order to prevent ground loops. Once we changed that to the common 10R to gnd connection, not a single opamp blew up again (those were potted and expensive as well). Another thing is with some stuff (probably a discrete opamp as well) inside the dangerous monitoring system, I was told that they blow up if they get connected to dc - in this case an iphone headphone output. Maybe this helps to prevent the damage in the first place...

Michael

[Chuckles]

Repairing them is no issue. Only of you make them to sell to others is an issue.

The item must have a patent number on it. Look it up. There are several free patent look up sites. If the patent is over 17 years old, it is public domain now.

If the op-amps are a module in the `2520` pin format there are many other ones you can buy with excellent performance. Or you can make your own discrete component op-amps. There are many designs out there that re very good.

[simonsez]

 

[ruffrecords]

ps, they specifically said they would involve lawyers if i shared what i found underneath the potting compound.

They cannot do that. As the thing is in a product available to the general public it is automatically public domain. You are free to take it apart , draw the schematic and post it anywhere you want. That is not infringing their intellectual property. If the circuit is patented then there must be a patent somewhere that contains the schematic. The patent is public domain therefore the schematic must also be. You have to provide sufficient information in a patent such that 'one skilled in the art' could reproduce the idea.

If it is patented and you start making and selling them then that is an infringement and they will quite rightly get the lawyers involved. As someone else said, if it is patented ask them for the patent number. There are free databases where you can read any patent. Anything in the patent is public domain and you can post it here.  If the patent is pending, then you cannot infringe because the patent has not been granted. You can build and sell as many as you like until then,

BTW IANAL but I have a few patents to my name.

Cheers

Ian

[john12ax7]

They cannot do that. As the thing is in a product available to the general public it is automatically public domain. You are free to take it apart , draw the schematic and post it anywhere you want. That is not infringing their intellectual property.

Is this correct,  do you have a reference? I would think if you reverse engineer and post details of a commercial product it would be an issue. Would apple allow you to post schematics of an iPhone? Would Microsoft allow you to post Windows code? Don't think they are patented.   

[warpie]

I would think if you reverse engineer and post details of a commercial product it would be an issue.
 

Don't know whether it would be an issue or not but (if you ask me) it's totally unethical.