What is the problem with the 10 ohm resistors, Mark? Am I missing something? The 10 ohm resistors are a crude current limiter for the fast, but very fragile driver transistors (RCA).
The JC-3 was designed as a tweeter amplifier in 1974 (45 years ago), and it was my first attempt to make a 100V/us power amp, following Otala guidelines. I gave this design to Mark in 1975 to make. I never got paid for it. It later became the ML-2 (initials changed to keep me from suing) and the final version of it is considered one of the 12 most famous amplifiers in the world today, tube or transistor. This schematic was published by me in 1981, from an internal Levinson document, in TAA, since I still wanted some credit for the design, even if I was not paid for it. The actual ML-2 was more complex, but it isn't necessarily 'better' than the JC-3, just more output transistors, etc. Tom C, then Mark's in house designer went out of his way to make it different from the original prototype shown here.
The JC-3 was designed as a tweeter amplifier in 1974 (45 years ago), and it was my first attempt to make a 100V/us power amp, following Otala guidelines. I gave this design to Mark in 1975 to make. I never got paid for it. It later became the ML-2 (initials changed to keep me from suing) and the final version of it is considered one of the 12 most famous amplifiers in the world today, tube or transistor. This schematic was published by me in 1981, from an internal Levinson document, in TAA, since I still wanted some credit for the design, even if I was not paid for it. The actual ML-2 was more complex, but it isn't necessarily 'better' than the JC-3, just more output transistors, etc. Tom C, then Mark's in house designer went out of his way to make it different from the original prototype shown here.
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Well Sir, would you, please, indicate me the schematic of the circuit mentioned in the title of this topic?
I didn't hear it but i heard a home made Hiraga , 50kg for 2x 30w/8ohm or something like this...and it put to shame about 10 valve amps...It was funny as it was a valve audiophiles meeting and when the guy turned his Hiraga on ...nobody wanted to listen any valve amplifier anymore.
Maybe Mark Levinson was famous in the US, we had Hiraha here...same 1977...when i was born 🙂
Maybe Mark Levinson was famous in the US, we had Hiraha here...same 1977...when i was born 🙂
So much for providing a "working" model and more evidence that you can patent anything.
Not much difference to what respected western companies did to JC's and uncountable others' IP. They understand enough about capital, power and profit. Common practice, no need to fuss, won't change anything. 🙁
Please don't bother with this nonsense, it's a waste of time. This place is beginning to remind me of USENET.
The value of a man is in the quality of its enemies .
I admire you both anyway for what you have done in the past , but we are all human.
I admire you both anyway for what you have done in the past , but we are all human.
Not sure what you're asking as this question can be parsed a few ways. Violation of a patent basically IS theft of IP, but the patent holder has to sue in civil court to get remediation, so it' not really "criminal." I've heard of cases where after a lawsuit imported IP-infringing products are confiscated or destroyed by authorities, but that's unusual.
But the the video does pretty much describe how US patents work, they're basically corporate trading cards. There are so many patents (and written in the most general way possible and still pass the patent examiners) that it's inevitable that some corporation will infringe on something, and when this is brought up, the infringer looks through its own patent inventory and the other's products for something that likely infringes, the two companies sign cross-licensing agreements, shake hands and go on their way.
Patents don't do much for the small guy without the money (or a near-lifetime of tenacity) to sue (ahem, Robert Kearns).
There's the story at the local "hackerspace" of a guy who showed up out of nowhere and was all excited about this idea of lifting a door key outline from a photograph and 3d-printing a duplicate key. He wasn't interested in the technology, didn't care exactly how it was done, in fact he wanted others to do all the work for him (it's amazing how transparent some people can be). He was basically told to go elsewhere.
It doesn't need to be as complex as semiconductors for something to go wrong, but if your product works for six months to a year (whether it's bad capacitors or computers that use them), you can get away with selling them for quite a while.
Tale of bad capacitors taking a company down
The 743 and 797 datasheets were all mine, virtually every word of any technical import.
I was asking a very specific question, in many cases I doubt there was any patent protection. The usual scenario is that folks simply think that if someone spends a lot of effort to put out a product there should be some kind of de facto protection from clones or copies.
Then you are responsible for all my future faults 🙂
May i know anything about ad835 author?
That would be Barrie Gilbert but he had a lot of help (by choice). I often sat at the bench building and testing everything on the datasheet.
It's designed by great Shunyata. You have to hear the difference! Someone with decades of experience in audio said, "If your answer is "No, I can't" you have a problem. Or your system is very bad, or your ears."
Oh, I have good remembrances of the news groups.
At least at the begining. It seems forums tend to disappear the same way, with the same phenomena near the end ;-)
Scott,
the AD 743 was discontinued over a decade ago (usually because a better op amp replaces the prevoius generation) yet it was only just recently that jfet input op amps with lower noise became available. Was it process yield issues or ?
the AD 743 was discontinued over a decade ago (usually because a better op amp replaces the prevoius generation) yet it was only just recently that jfet input op amps with lower noise became available. Was it process yield issues or ?
the David Grohl Neve is not full of NE5534s. It does have oamps, discrete ones, with feedback into the single input transistor emitter. Does that make it CMA?? 🙂
The total count of opamps in that console was about 6 per channel module (mic pre, EQ, line In, fader buffer, and output). One more for summing and another for output. Not that many.
But later in the V series days, oy vey, would you like a dozen or so chips? or more. Lets put it this way, there were 150 caps in an input channel strip. Maybe a normal board had 48 channels, dbx2151 VCAs to control the monitor gain, another vca pair to control and process the mix buss, etc etc, Not a thing of simplicity. So hot above it you sweated as you worked.
Cheers
Alan
The total count of opamps in that console was about 6 per channel module (mic pre, EQ, line In, fader buffer, and output). One more for summing and another for output. Not that many.
But later in the V series days, oy vey, would you like a dozen or so chips? or more. Lets put it this way, there were 150 caps in an input channel strip. Maybe a normal board had 48 channels, dbx2151 VCAs to control the monitor gain, another vca pair to control and process the mix buss, etc etc, Not a thing of simplicity. So hot above it you sweated as you worked.
Cheers
Alan
I am not surprised that the better Neve boards might use discrete op amps. I did the same thing, when I built studio boards. That discrete op amp is what I used to directly compare the 5534 and it to evaluate their relative qualities. Unfortunately the 5534 lost (slightly) in the listening test comparison and I was forced to keep making discrete plug in modules. It would have saved me a lot of time and money, IF I could have used the 5534 with good conscience instead of discrete modules, but I would not be as appreciated as I am now, if I had compromised. In return, years later Dave Wilson first gave me a WATT-Puppy speaker system in 1989, and later the Sashas a few years ago, for his appreciation of my efforts in making circuits for him, in the past. It feels good to not have to compromise on at least a few projects.
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