scott wurcer said:
john curl said:
You didn't answer the question, John! But then you don't have to 😀
I just checked out a 2N4405, sitting in a drawer for 40 years. It measures about .7nV/rt Hz at 2.5ma. Four in parallel = 0.4nV/rt Hz. 16 in parallel = 0.2nV/rt Hz.
Of course I could use the Hitachi, Fairchild, or Rohm devices (all 30 years ago), and I should get 0.2nV/rt Hz with maybe 4 to 8 devices. So what?
Of course I could use the Hitachi, Fairchild, or Rohm devices (all 30 years ago), and I should get 0.2nV/rt Hz with maybe 4 to 8 devices. So what?
john curl said:
I have answered before you asked:
http://www.diyaudio.com/forums/showthread.php?postid=1837220#post1837220
I've heard one or two high end systems in my day. Even built a few. 😀
I have to say, a few years ago while I was at the European Triode Festival, I heard a single driver system with 1940's vintage drivers and a single-ended tube amp that I'm sure had specs as poor as the Lamm. But the experience was lovely, I could spend hours listening to it (and did). I would not say that it was "fool the ear" real, just pleasurable and easy to listen to. The audio equivalent of spiking a dish with a bit of sugar and MSG.
So that's the secret to tube's success, distortion!
I am in the wrong business, I have been trying to remove distortion, without screwing anything else up for decades. I should just let go!. 
I am in the wrong business, I have been trying to remove distortion, without screwing anything else up for decades. I should just let go!.
That's exactly what the SET brigade would say, yes. They claim that distortion is unimportant, it's the "beauty" of an amp's sound that matters. And I've seen claims that the high distortion partially cancels speaker distortion. Whatever. My philosophy is closer to yours- I don't want the amplification chain editorializing- but there are many different philosophies. My equipment uses tubes, but the distortion levels and source impedances are too low to suit SET aficionados.
SY said:
This canard about tubes sounding different from sand because they add 2nd harmonic distortion is demonstrably untrue. Hook up your computer to your stereo, play some music, and run a filter to add 2nd order harmonic distortion. Does it sound like a 300B? Tubes sound good in spite of their distortion, not because of it, and as you know, they tend to sound better with less.
john curl said:So that's the secret to tube's success, distortion!
It is, however, the case that odd distortion sounds worse than even. The reason is that the brain stem responds to consonance and dissonance differently, effectively adding additional components depending upon what you hear. That is, if you hear consonant sounds, the brain stem adds more consonant harmonics. If, on the other hand, you head dissonant ones, it adds additional dissonance.
Moreover, musicians hear this stuff differently than engineers:
http://www.soc.northwestern.edu/brainvolts/documents/Lee_et_al_JofNeuro2009.pdf
http://www.soc.northwestern.edu/brainvolts/documents/KrausSkoePClarkAshley_Annals_Rev1.pdf
dsavitsk said:
Very interesting links, thank you!
From the 2nd:
"From the cochlea to the auditory cortex, sound is encoded in multiple locations along the ascending auditory pathway, eventually leading to conscious perception. While there is no doubt that the cortex plays a major role in the perception of speech, music and other meaningful auditory signals, recent studies suggest that subcortical encoding of sound is not merely a series of passive, bottom-up processes successively transforming the acoustic signal into a more complex neural code. Rather, subcortical sensory processes dynamically interact with cortical processes, such as memory, attention and multi-sensory integration to shape the perceptual system’s response to speech and music."
(Bold type mine). Are you in any way involved in this type of research?
Jan Didden
janneman said:
My wife is one of the authors on the papers. So, I offer moral support 🙂
Here's the lab's homepage: http://www.soc.northwestern.edu/brainvolts/
Joshua,
The idea is to separate the current carrying leads from the sense leads that sense the voltage across the resistor. That avoids errors due to voltage drop across (part of) the current carrying leads.
Jan Didden
The idea is to separate the current carrying leads from the sense leads that sense the voltage across the resistor. That avoids errors due to voltage drop across (part of) the current carrying leads.
Jan Didden
SY said:
If they're both compressive that would be unlikely. Seconds could be made to do this I suppose, an interesting idea. OTOH the load drive/impedance issues are separate from the THD ones and can be demonstrated to be audible.
Those that argue, "but tube amps sound better with less distortion," will probably not argue that they sound better with high Aol and feedback to get low damping factor.
There's an inconsistency in the thinking. Futterman amps, for example, come highly praised, despite having the highest feedback factor of any commercial tube amps. Their marginal stability and poor reliability have no doubt contributed to the legend (the closest solid state equivalent I can think of is Rappaport).
Second cancellation was the subject of a paper I saw a year or two ago by a guy named (I think) de Lima. Holes in the argument that would make Swiss Cheese proud, but the amps he makes are very highly thought of.
Second cancellation was the subject of a paper I saw a year or two ago by a guy named (I think) de Lima. Holes in the argument that would make Swiss Cheese proud, but the amps he makes are very highly thought of.
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