Lyngdorf already do that, my friend has one. EQ and all the gizmos, yet I still don't love it ;-)
Have you noticed that when you are talking about audiophiles all your logical thinking is thrown into waste basket and all kind of weird assumptions and generalizations come in? Behavior you don't let other people have around you, without an argument or questions. I have seen it happen more than once times now.
Most, so called "audiophiles" i know are using xlr cables. Many "audiophile-grade" devices don't even have possibility of using RCA. I am also using xlr cables, if you like to think me as an audiophile. I don't know where you get this "audiophiles tell xlr cables are not real hifi". Maybe it is just your own imagination or maybe you have just read such things in some anti-audiophile forums?
It just makes me sad to read about such nonsense claims you are sometimes writing about other people you call "audiophiles". It's almost like tribal behavior and building the hate and despise towards this opposing tribe, which doesn't even exist.
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You definitely have a point, I shouldn't be using the word "audiophiles" that way. But the tribe definitely exists. What word do you suggest I should use for "the vocal, aggressively subjectivist crowd that dominates most audiophile forums"?
Come on! You know the term: "THE GOLDEN EARS"!
"I know what I hear - nothing else matters"
Let them audiophile forums be audiophile forums. How about that? There is no war going on. Lower your spear and relax and listen to the beautiful music. We are all friends here. Flowers, sunshine and all that... 🙂
Flowers, sunshine and all that would be great, if it wasn't for the fact that a significant fraction of the golden ears *are* at war - against science, physics and rational thinking.
Note that I have let audiophile forums be - there are more important things in life than fight a futile fight against faith and superstition. But this is not an audiophile site - this is a DIY audio site. So science and physics are not completely banned, and reality enters, at least occasionally.
So, how is it working? Fighting the people of "faith and superstition" by putting words in their mouth they are not even saying, but are just product of your own imagination and/or other templars of science. Some people call that denigration of some "lesser group of people".
Like in this claim that the "audiophiles" are saying that "XLRs are only for the pro stuff", even there is no consensus of such claims and nobody knows a person that has actually said such things. And nothing supports such claims.
To me, the main problem of "pure science based objective truth"-hifi is that it worked if the people making the music would be pure science based individuals. But too big portion of music is ruined already when recorded. That end should have better standards of quality as well. Because more objectively perfect you system is, more likely are those mistakes hearable. And nothing is more annoying than bad use of microphone.
If i for instance use cables and opamps and what-not to deviate just a bit from the objective perfection to hide things/truths from me that i find just too annoying, do i turn from good guy to a person of "faith and superstition"?
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So I finally got around to doing something I've been meaning to do for awhile now. I did a quick model in LTspice of the "recommended" input buffer design alongside the model outlined in the NC500 data sheet application hints for modelling input buffer current demands.
See pic 1 for a screen shot of the model. The first box adds the EMC/ESD/DC blocking components one would expect to see in the actual circuit. Then there's the simple input buffer. The last box is the Fig 2 for estimating input current to the amp module.
Now to look at a couple of the points made earlier in this thread. Do the 47k resistors add a lot of noise to the circuit? Not at all. Pic 2 shows a .NOISE analysis and the output probing the two 47K resistors. The noise contribution from these is trivial at best if properly implemented.
Secondly, the third pic looks at the output current required of the two LM4562 op amps. Note that this is with a 2.5Vp input voltage, leading to output voltages in excess of 100V - above the limits of the amp. Lower volumes mean a lot less current from the input buffer.
See pic 1 for a screen shot of the model. The first box adds the EMC/ESD/DC blocking components one would expect to see in the actual circuit. Then there's the simple input buffer. The last box is the Fig 2 for estimating input current to the amp module.
Now to look at a couple of the points made earlier in this thread. Do the 47k resistors add a lot of noise to the circuit? Not at all. Pic 2 shows a .NOISE analysis and the output probing the two 47K resistors. The noise contribution from these is trivial at best if properly implemented.
Secondly, the third pic looks at the output current required of the two LM4562 op amps. Note that this is with a 2.5Vp input voltage, leading to output voltages in excess of 100V - above the limits of the amp. Lower volumes mean a lot less current from the input buffer.
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I gave the Sonic Imagery 994 another chance even tho it is having lots of background noises. Tbh, i am really liking it. I hope the rev C board is coming soon. I did not bother testing it longer periods earlier.
Boggit, you gonna offer the rev C board as self-upgrade old customers, so no need to send the amp to you? What i meant with testing with other opamps is that, testing that the board has at least similar compatibility with a subset of opamps: Sparkos/Burson/LM4562 and if possible with OPA2132P and LME49860. I didn't expect compatibility with every opamp, since it is impossible.
Boggit, you gonna offer the rev C board as self-upgrade old customers, so no need to send the amp to you? What i meant with testing with other opamps is that, testing that the board has at least similar compatibility with a subset of opamps: Sparkos/Burson/LM4562 and if possible with OPA2132P and LME49860. I didn't expect compatibility with every opamp, since it is impossible.
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You cannot possibly expect Boggit to factor in safeguards for op amp instability across an infinite number of op amps. Why don't you, assuming you've selected the SI OA, solder the necessary caps yourself?
But...that i was saying too in my previous message, if you read it more carefully. At least that was my intention. There is some bad english tho, sorry about that.
I was just worried, that if i upgrade to rev C board, do these currently working opamps work anymore with that board and it will be kind of "compatible-with-994-only" input board. Currently working are the Sparkos, Burson and LM4562, and maybe also couple other opamps if possible - OPA2132 and LME49860 which are not particularly sensitive to going unstable. Not infinite number of opamps. Where did you get that number.
But then again, if "compatible-with-994-only" input board is the only way to go, then i guess thats the way it is done.
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That new circuit will lower the noise for all opamps. But it won't increase the current output capabilities of the opamps used. Nerdman's claim of 70mA being required out of the opamps for full amp output seems a bit extreme to me. 10-12mA is what I had figured. The Sparko runs in class A up to 15mA, and the SIL 994 runs in class A up to 30mA. The max capabilities of the Burson V5 is only 14mA. So if it's true that 70mA is required for full output, this means the Burson is way underpowered, along with most IC opamps you tested.
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That sounds very promising.
Well, that is a bit downside. Well, we'll see how it goes. If that "full output" is as in "full power", its not something i need to worry about tho.
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No it won't
Lowering the 47k resistors increases noise in the circuit. This is opposite to the blind application if "bigger resistor = more noise" but the reason why should be obvious. The noise of the 47k resistors is filtered by the dc blocking caps and the resistance, low pass filters. There is a divisor at work 2.Pi.R.C. Lowering R reduces the divisor. See first pic.
As I have said before, the predominant sources of noise (assuming a properly behaved op amp) in the buffer circuit are, unsurprisingly, the resistors in the signal path. The noise of the 1.5k resistor, for example, dwarfs the 47k and any sensible op amp choice. It is closely followed by the 3.3k.
I welcome anyone to point out errors in the technical analysis.
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That's an invented construct if I ever heard one. I am just as much turned off by the crusaders who wants to set the world straight and look down on others with long noses. Often it just introduces a new set of 'truths' and new myths. YouTube is full of it. You can sometimes chuck out the baby with the bathwater by getting too stuck on orthodoxy.
No doubt there are crazy people out there, in any obsessive endeavour that is to be expected, but in the land of Audiophilia there are no more than in other equally obsessive fields. And we are admittedly an obsessive bunch. Don't get upset, just have a good laugh.
My favourite one is that the diameter of my speaker wires are not thick enough, so I bought a couple of hose lengths and put them inside and put heatshrink on the ends to cover up, then they asked where they could buy them. Just good natured fun and harmless. 😀
I am both an audiophile (lover of good sound) and a music lover - and proud to be both.