The intelligence of this woman, her enthusiasm, something so beautiful that emanates from her can bring tears to you as the greatest musicians can do.
YouTube
Something very rare and precious, the same simplicity, the same emotion.
YouTube
Succeeding to get the picture of the invisible from the idea that everything in the universe obeys the same forms, the same harmonies, the same rythmes, those same of our daily life, is, somewhere, to approach a mystery greater than the one of a black hole. A mystery that some people call, without being able to define it, "God".
Thinking to this, the word is not the right. Sensibility, passion, something of the order of love, obviously supported by a great scientific rigor.
This should give us a subject for meditation, in order to solve this eternal conflict between those whom some call objectivists and those whom others call subjectivists. We have a French proverb that says "Science without conscience is the ruin of the soul".
We should add "Feeling without science" as well.
I'm thinking of this morning, where Albert Enstein awoke with this strange intuition of what he called relativity. As a musician wakes up with a melody, without knowing where it comes from, but who feels it's right. And who spent the rest of his life basing it on calculations, as a musician writes the arrangements.
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Nostalgia is a rosy sentimentality of the past, playing records is more like those reenactment groups, fun for those of that persuasion.
My experience with RIAA
I jumped only now in this thread and I read only the last few pages: sorry for that.
I would like to share my experience with RIAA amp.
In 1980 I built a MC RIAA amp made with a discrete op-amp with a dual low noise NS jfet (U306) in the diff-amp and with the VAS loaded to get an open loop gain replicating the RIAA curve, to have the possibility to apply a constant feedback up to over 20 KHz, with the classical active RIAA in the feedback loop (2 C and 2 R). The sonic result was not so bad. Some year later I modified it by putting a passive RIAA between 2 discrete op-amp card and the sonic benefits were evident . I lived with this RIAA for more than 30 years with great pleasure.
Only in 2010 I discovered an interesting current feedback op-amp (AD844) and I decide to try a no-feedback MC RIAA with it, by putting the RIAA network on its compensation pin to shape its open loop gain to follow exactly the RIAA curve (I prepared an Excel sheet to size all the RIAA components and to check the accuracy of the network in front of the theoretical time constants transfer function. The RIAA network was sized to get the MC gain by selecting the components values to obtain my desidered gain by taking in consideration the impedance of the pin 5 (TZ node) in parallel with it. The noise level was very good and expecially the pulse response was optimal (my primary goal in this design) with a great benefit on its sonic behaviour.
I think that these two design are alternatives to the one discussed here and they can overcome some of the limits of the other architecture described.
By the way, I own a wonderful sounding Dennesen JC80 (John design), too. I love it very much!!
Cheers
I jumped only now in this thread and I read only the last few pages: sorry for that.
I would like to share my experience with RIAA amp.
In 1980 I built a MC RIAA amp made with a discrete op-amp with a dual low noise NS jfet (U306) in the diff-amp and with the VAS loaded to get an open loop gain replicating the RIAA curve, to have the possibility to apply a constant feedback up to over 20 KHz, with the classical active RIAA in the feedback loop (2 C and 2 R). The sonic result was not so bad. Some year later I modified it by putting a passive RIAA between 2 discrete op-amp card and the sonic benefits were evident . I lived with this RIAA for more than 30 years with great pleasure.
Only in 2010 I discovered an interesting current feedback op-amp (AD844) and I decide to try a no-feedback MC RIAA with it, by putting the RIAA network on its compensation pin to shape its open loop gain to follow exactly the RIAA curve (I prepared an Excel sheet to size all the RIAA components and to check the accuracy of the network in front of the theoretical time constants transfer function. The RIAA network was sized to get the MC gain by selecting the components values to obtain my desidered gain by taking in consideration the impedance of the pin 5 (TZ node) in parallel with it. The noise level was very good and expecially the pulse response was optimal (my primary goal in this design) with a great benefit on its sonic behaviour.
I think that these two design are alternatives to the one discussed here and they can overcome some of the limits of the other architecture described.
By the way, I own a wonderful sounding Dennesen JC80 (John design), too. I love it very much!!
Cheers
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My point exactly. I would think OTOH the AD844 input pair (IIRC ~2nV) is more noise than you might want for some carts.
What does this have to do with sound replaying electronics which was created by electrical science in modern era?
Scott,
you recall correctly: 2nV/Root(Hz) is the typical value on the DS.
For this reason, I selected the AD844 to be used for the lower noise. Anyway, my cart has 0,3mV output and the noise is barely audible by putting my ear very near to the speaker (ELS in my case).
My experience too, many years ago even a 4nV amp was barely audible with a medium output MC. I just find discovering how well some simple circuits can work without serious compromise can be fun.
I'm beginning to think the Pass Labs folks have more fun.
I'll not question how anyone has their fun. I'm a heretic after all. But it's fun to hack back the weeds on the paths less trodden.
I am using a BF862 with a PNP gm helper. With two active signal amplification devices and judicious selection of the source and feedback resistors (AV=8 to 16) you get to 1.5nV/rHz. If you parallel three JFETs you get below 1 nV/rHz. The power supply is half an LM4562 - you could use the other half for a MM EQ stage.
Simple is always better . . .
Simple is always better . . .
I don't think so thanks, the non-symmetry could help from a bass perspective due to room modes by not for time relevant imaging cues.
Which is why I like the basic AD524 architecture. Two bipolars and two opamps for a balanced input at under 0.5nV/rtHz.
The Demrow circuit (1968) I was simply the first person to put it all on one die.
I agree it's fantastic part but I don’t see 0.5 nV/rHz - do you mean 0.5 uV wide band noise RTI?
John, hundred posts ago you mentioned the gentleman, who tunes listening rooms. Was it Bob Hodas?
Poor choice of words on my part. I should have said 'Demrow INA' but figured more people would be aware of the implementation in the AD524. With the ZTX851 and a good low noise opamp with enough current drive you get MC noise performance good enough for most sane MCs. And it's balanced which I personally consider a must have.
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