I think that both hi end and AES are important, BUT for different reasons. AES for a few, very few really useful engineering dissertations, old friends, and new audio gadgets.
Hi end for what is REALLY possible sonically by people who really love audio, and are willing to invest heart and soul into it. Usually the sound quality at the AES is awful, and Hi End sometimes amazingly good! Why, nobody knows, at least not yet.
Hi end for what is REALLY possible sonically by people who really love audio, and are willing to invest heart and soul into it. Usually the sound quality at the AES is awful, and Hi End sometimes amazingly good! Why, nobody knows, at least not yet.
Demian, your 1710 is not showing any 7th harmonic in the residual, but EVERY op amp that I tried as a phono input stage seems to have lots of 7th harmonic. Today I tried the 711, 817, 411, and 797. All pretty bad, even at 1KHz. Your analyzer is having trouble nulling and it has a noisy front end, as you probably know. I know how to fix that in principle, the noisy front end, that is, and it is accessible. I opened the top and looked.
john curl said:Jan is a non-believer.
No, not really. I believe that every man needs a believe in order to stay sane 😉
It's just that I don't believe in authority, tradition and religion as a source of THE TRVTH (tm), remember?
As to the Munich Hi-end show, here is my report of last year's event:
http://www.audioxpress.com/magsdirx/ax/addenda/media/didden_munich.pdf : 'A tribute to 2-way analog stereo' .
Do I get extra points now?😀
Jan Didden
I am looking pretty deep down in distortion, but if I can see it, then it is too much for easy analysis.
that paraphasing is back to front.scott wurcer said:
The opposite is what is claimed to have happened.
The Patent was restricted to two devices in one package. As a result Darlington and Bell Labs did not get royalties for every IC that was produced (within the time limit).
One of the real problems with getting a patent is that someone can use it by making a minor change in their design, and say that your 'uniqueness' as described in the patent is not used.
We made the mistake (the lawyers and me) of describing my design as a 'plurality of complementary pairs' rather than 'single or plurality of complementary pairs' (of a specific topology) and Ortofon used that to get by my patent, even though we had offered to license them years before with the same basic design that they ultimately used, and I did a 'dog and pony show' on their blackboard in Copenhagen to show the ADVANTAGES of the circuit topology, as proven here recently by PMA, in an earlier simulation.
It is surely a wake-up call to be dismissed, after the effort and cost for getting a patent on a unique topology, and then trying to promote its use. And you guys wonder why I am such a curmudgeon.
We made the mistake (the lawyers and me) of describing my design as a 'plurality of complementary pairs' rather than 'single or plurality of complementary pairs' (of a specific topology) and Ortofon used that to get by my patent, even though we had offered to license them years before with the same basic design that they ultimately used, and I did a 'dog and pony show' on their blackboard in Copenhagen to show the ADVANTAGES of the circuit topology, as proven here recently by PMA, in an earlier simulation.
It is surely a wake-up call to be dismissed, after the effort and cost for getting a patent on a unique topology, and then trying to promote its use. And you guys wonder why I am such a curmudgeon.
PMA, on closer inspection, I am getting essentially the same amount of 7th harmonic distortion as you are in your measurement. Not good enough.
Lancaster seems to go a bit overboard here, but I believe much of what he says is true:
http://www.tinaja.com/patnt01.asp
I believe that the patent system has degraded to the point where it is only effective for large businesses that can afford the legal fees to enforce. Even then, they use strong arm tactics. I have some experience with the system and am the inventor on 3 patents.
http://www.tinaja.com/patnt01.asp
I believe that the patent system has degraded to the point where it is only effective for large businesses that can afford the legal fees to enforce. Even then, they use strong arm tactics. I have some experience with the system and am the inventor on 3 patents.
AndrewT said:
That was not my point the patent would have expired in 1966 when the IC was still in its infancy and everyone had to pay to licence the planar process anyway ($75 op-amps).
Does Lancaster still use a printer as a primary computer programming directly in postscript?
Good old Don Lancaster. Bought his book on filter design, 35 years ago. Saved my SOCKS!
Very special guy, high intuition.
Very special guy, high intuition.
I would agree - some have appreciated the sound of that opamp based MC pre, some not so enthusiastically.
Different situation from the discrete line preamp, which was accepted very well.
Different situation from the discrete line preamp, which was accepted very well.
PB2 said:
We should keep the OT patent stuff to a minimum, but Mr Lancaster also has some misconceptions. A granted patent stands until invalidated. It does not really matter which one of the faux pas the applicant committed. This will cost you a cool $1,000,000 in legal fees.
PMI please remember that I am making 2 separate phono stages. One discrete and one with IC's. Parasound specifically asked me to avoid difficult to get parts, etc. Also, cost and board size are paramount. I will do the best that I can with the best IC's I can find. The AD797 qualifies as the best IC that I can find for a low noise input stage, and low distortion, as well. Unfortunately, I can't run it open loop like Dick Sequerra does, as I don't have the time or skill to do that right, but let's see what we can do with feedback and neutralization. Some of the parts are compromised as well including using ceramic caps as .1 uf bypass. Maybe I will improve on that in future. Still, the virtually perfect power supply rejection of the AD797 should protect us from any problems
caps as .1 uf bypass. Maybe I will improve on that in future. Still, the virtually perfect power supply rejection of the AD797 should protect us from any problems
I don't know what Dick is doing either. The pin that would enable this was not made available. BTW it does work very well, I had some test chips run for GE ultrasound that were truely open-loop. They were not considered "commercial potential" since the function was dragged on to a larger analog front end chip.
Of course you don't, Scott. You have never asked Dick. He is still available, I just spoke to him this weekend. You will have to ask, because Dick does not like to make you uncomfortable, as I am prone to do.
john curl said:
This is really a pain, and no other way when building a commercial design.
Also, this is the reason why I took bipolars for my discrete design.
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