Ralf11 Posted July 3, 2017 Share Posted July 3, 2017 well, do you accept his stmt. that every component (even passive ones, and even resistors) has a non-linearity? and further, that those non-linearities can be heard when listening to music? if so, it necessarily follows that every amp will have a sonic difference But, I think a better approach is to look at the amp driving a speaker (i.e. a complex load) and find non-linearities there... semente 1 Link to comment
AJ Soundfield Posted July 3, 2017 Share Posted July 3, 2017 15 minutes ago, Ralf11 said: well, do you accept his stmt. that every component (even passive ones, and even resistors) has a non-linearity? and further, that those non-linearities can be heard when listening to music? Evidence? Once again, with honesty controls, just listening, trust ears, no peeking. Otherwise, no. Link to comment
jabbr Posted July 3, 2017 Share Posted July 3, 2017 20 minutes ago, AJ Soundfield said: Evidence? Once again, with honesty controls, just listening, trust ears, no peeking. Otherwise, no. Thankfully with science, observations are generalizable. My statement is made not, duh, by actually measuring every resistor, rather per physics. Don't take my word for it, feel free to take a class -- I hear there are excellent classes online these days. Albrecht 1 Custom room treatments for headphone users. Link to comment
Popular Post jabbr Posted July 3, 2017 Popular Post Share Posted July 3, 2017 43 minutes ago, Ralf11 said: and further, that those non-linearities can be heard when listening to music I can state with confidence that all amplifiers, even copies of individual brands, will have measurable differences. I am not making such an absolute claim to audibility -- let's say that amplifiers often have a sonic signature Albrecht and MikeyFresh 2 Custom room treatments for headphone users. Link to comment
AJ Soundfield Posted July 3, 2017 Share Posted July 3, 2017 24 minutes ago, jabbr said: and yes, each amplifier in existence has its own sonic signature determined by the non-linearities in its components. Thankfully with science, observations are generalizable. My statement is made not, duh, by actually measuring every resistor, rather per physics. Don't take my word for it, feel free to take a class -- I hear there are excellent classes online these days. I am not making such an absolute claim to audibility -- let's say that amplifiers often have a sonic signature Maybe you could take an online class about decision making and logic. Now please provide the evidence for the latter claim, thanks. Link to comment
Ralf11 Posted July 3, 2017 Share Posted July 3, 2017 34 minutes ago, jabbr said: I can state with confidence that all amplifiers, even copies of individual brands, will have measurable differences. I am not making such an absolute claim to audibility -- let's say that amplifiers often have a sonic signature sounds about right Link to comment
fas42 Posted July 3, 2017 Share Posted July 3, 2017 8 hours ago, semente said: The same is valid for listening. Depending on the listener's experience of both live and of reproduced sound as well as his taste in sound, a report describing an amplifier that "disappears and leaves the music for you to enjoy" can be more or less meaningful. To be honest I am always sceptical of reports that talk about enjoying the music, an expression that also comes up in discussions involving measurements and poor technical performance. And if soundstage is mentioned in the first couple of paragraphs I just stop reading. Extremely impressive soundstage just automatically manifests if the reproduction is half reasonable - I don't see how it would be possible for it to be otherwise. Amplifiers, or more accurately, systems "disappear" in the sense that a particular recording will always sound the same - a very useful approach is to assess a new, unknown setup by playing well known recordings and asking, how much is missing, how much mangling of that recording am I hearing? On extremely rare occasions one can hear a slight addition of information in the recording, because the particular rig happens to be somewhat more adept in a particular area than what you've experienced up to now. Link to comment
Popular Post Superdad Posted July 4, 2017 Popular Post Share Posted July 4, 2017 1 hour ago, jabbr said: I can state with confidence that all amplifiers, even copies of individual brands, will have measurable differences. I am not making such an absolute claim to audibility -- let's say that amplifiers often have a sonic signature During my years at Hovland Company, we would make small "in-line" production changes and improvements (sometimes just a single resistor change--of value or composistion), and these were not announced, even to our largest overseas distributors, unless there was a real need to, because otherwise they would want all their inventory and demo units swapped out or upgraded--a HUGE expense. Much of the time nobody would say anything, mostly because their dealers and the end users would just get the latest and be happy. But our big German and Japanese importers were very, shall we say anal, and they listened to almost every amp and preamp unit before delivery to their dealers. And almost invariably I would get a call from them reporting that the new shipment sounded very different and demand to know what we did--and could we update their demo units. (Luckily they both had good techs and most of the time we could just send them a few parts and instructions.) Of course the above proves nothing to those who hear nothing... jabbr, Teresa, Albrecht and 1 other 4 UpTone Audio LLC Link to comment
jabbr Posted July 4, 2017 Share Posted July 4, 2017 2 hours ago, AJ Soundfield said: Where can one find the details of this? There are many many discussions of resistor noise and nonlinearity e.g.: https://www.ap.com/technical-library/from-the-test-bench-resistor-noise-and-non-linearity/ http://www.vishaypg.com/docs/60108/VFR_TN108.pdf http://www.analog.com/en/analog-dialogue/raqs/raq-issue-25.html http://physics.princeton.edu/~mcdonald/examples/statistics/dutta_rmp_53_497_81.pdf https://peteinthelab.files.wordpress.com/2011/04/noisepaper6510.pdf there are also discussions of nonlinearities and noise in other components e.g. capacitors. differences in transistors are very very well known. However, if you look at the Analog Designs paper, they discuss that resistor noise is often the limiting factor... Noise itself is fundamental: https://www.physics.utoronto.ca/~phy225h/experiments/thermal-noise/Thermal-Noise.pdf ... Really this is all physics Custom room treatments for headphone users. Link to comment
Ralf11 Posted July 4, 2017 Share Posted July 4, 2017 we do need to be careful with some of these findings - e.g. we won't be operating any components from 350 K to 4.7 K so the Johnson noise may not be an issue; the same researchers (last URL) did find that 1/f noise was not T-dependent Link to comment
fas42 Posted July 4, 2017 Share Posted July 4, 2017 Signatures of systems are typically because of weaknesses in the implementation of the components, and insufficient integrity of the system as a whole - various electrical interference mechanisms are in play, just high enough in level to cause audible artifacts. STC 1 Link to comment
Popular Post Superdad Posted July 4, 2017 Popular Post Share Posted July 4, 2017 15 minutes ago, fas42 said: Amplifiers, or more accurately, systems "disappear" in the sense that a particular recording will always sound the same - a very useful approach is to assess a new, unknown setup by playing well known recordings and asking, how much is missing, how much mangling of that recording am I hearing? Another very telling metric for "transparency" is how different the overall character of each recording presents itself. If every record has the same general presentation in the room, then that system is the opposite of transparent (and frankly there are more than a few popular DACs that are guilty of this). The one thing that blows most visitors' minds about my room/system (heck it even blows my own sometimes when I explore albums I have not listened to in a while) is how one recording can bloom like mad into the space and create one sort of atmosphere, while another will sound radically different, intimate, small and tactile. Again, if most recordings have a similar character and room presence, that's the opposite of a transparent system. Flame away, but tell us what conventional measurements are going to correlate to that very obvious metric. Octavius, Teresa, Doak and 2 others 5 UpTone Audio LLC Link to comment
AJ Soundfield Posted July 4, 2017 Share Posted July 4, 2017 9 minutes ago, jabbr said: and yes, each amplifier in existence has its own sonic signature determined by the non-linearities in its components. I am not making such an absolute claim to audibility -- let's say that amplifiers often have a sonic signature There are many many discussions of resistor noise and nonlinearity e.g.: I know Physics. I asked for your "sonic" evidence, via "Just listening, trust ears" honesty controlled audition, not hand waving about resistor noise. Thanks sarvsa 1 Link to comment
jabbr Posted July 4, 2017 Share Posted July 4, 2017 21 minutes ago, Ralf11 said: we do need to be careful with some of these findings - e.g. we won't be operating any components from 350 K to 4.7 K so the Johnson noise may not be an issue; the same researchers (last URL) did find that 1/f noise was not T-dependent Of course, but 1/f noise causes different non-linearities. The AD article discusses the temperature dependent equation. There is also "shot noise" and I'm not sure if this is temp dependent either -- lots and lots of variables. Johnson noise can also have frequency dependency. Custom room treatments for headphone users. Link to comment
Popular Post The Computer Audiophile Posted July 4, 2017 Popular Post Share Posted July 4, 2017 3 hours ago, AJ Soundfield said: Wow, you've listened to every amp, with honesty controls (no peeking, etc. and "Just listening, trusting ears") in place. Where can one find the details of this? To be honest, this comment is so sophomoric. daverich4, Teresa and MikeyFresh 3 Founder of Audiophile Style | My Audio Systems Link to comment
Kimo Posted July 4, 2017 Share Posted July 4, 2017 Again, Nelson Pass isn't claiming transparency for these designs. He is claiming a highly musical enjoyable character. Freedom from the artifacts of negative feedback means greater transparency, even within the context of other design decisions. This is a pretty consistent design goal of Pass amplifiers. Link to comment
jabbr Posted July 4, 2017 Share Posted July 4, 2017 21 hours ago, esldude said: Now without the full regular measures at my disposal, I would venture a guess the J2 is going to be of lower fidelity because it has much more limited current capabilities. If someone says they listened to both and preferred the J2 that would not contradict this prediction. I think the real answer is speaker dependent. Sensitive speakers are necessary -- I've used full range horns and headphones --- this certainly isn't a Maggie deal. From a listening perspective the J2 sounds better to me with a smooth but solid high end and very controlled bass. From a realism point of view, I can often feel the bass with live music ... the J2 bass feels very controlled in its depths ... there's some prose that I was holding off giving .(and the M2 really is a terrific amp that folks should consider building -- parts are inexpensive) -- so I'd say J2 is more "accurate" Now I don't think I'm biased because I was really looking at the SIT-1 at the time (which I regret getting for other reasons) but the J2 just sounded so great (its all about the bass ) But you are making this prediction indeed without full regular measures at your disposal. Thanks for taking the time to read up on this and hopefully you can better understand my position -- I won't go so far as to ask you to agree Custom room treatments for headphone users. Link to comment
Kimo Posted July 4, 2017 Share Posted July 4, 2017 Since we are focusing on measurements and amps, I am currently listening to a push/pull integrated tube amp that claims a s/n ratio of >95. Is that even possible for tube amp? Link to comment
AJ Soundfield Posted July 4, 2017 Share Posted July 4, 2017 Ok, so zero evidence of "sonic signature" 1 hour ago, AJ Soundfield said: Quote 2 hours ago, jabbr said: and yes, each amplifier in existence has its own sonic signature determined by the non-linearities in its components. I know Physics. I asked for your "sonic" evidence, via "Just listening, trust ears" honesty controlled audition, not hand waving about resistor noise. Thanks Ok, so zero evidence for "sonic signature" Link to comment
esldude Posted July 4, 2017 Share Posted July 4, 2017 33 minutes ago, Kimo said: Since we are focusing on measurements and amps, I am currently listening to a push/pull integrated tube amp that claims a s/n ratio of >95. Is that even possible for tube amp? It could be. Which amp is it? You can make op-amp like circuits with tubes, and I seem to recall one design which basically did that, and combined with a good output stage achieved something near what you are listing here. And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. Link to comment
jabbr Posted July 4, 2017 Share Posted July 4, 2017 23 minutes ago, esldude said: You can make op-amp like circuits with tubes, and I seem to recall one design which basically did that, and combined with a good output stage achieved something near what you are listing here. The first "operational amplifier" was perhaps developed by Philbrick before WWII but published by Lovell & Parkinson, 1947 and implemented for the M9 antiaircraft gun targeting system as described in Johnson "Analog Computer Techniques", 1956 -- these were vacuum tube based of course, the circuits can be found in this book which is available used. and here: http://www.philbrickarchive.org/operational_amplifier.htm esldude 1 Custom room treatments for headphone users. Link to comment
Kimo Posted July 4, 2017 Share Posted July 4, 2017 18 minutes ago, esldude said: It could be. Which amp is it? You can make op-amp like circuits with tubes, and I seem to recall one design which basically did that, and combined with a good output stage achieved something near what you are listing here. Qualiton 50i. New to the USA. Doesn't look like a simple design. They wind their own transformers and utilize a more complex circuit design. You could understand it all, but it is beyond my humble comprehension. Link to comment
esldude Posted July 4, 2017 Share Posted July 4, 2017 8 minutes ago, Kimo said: Qualiton 50i. New to the USA. Doesn't look like a simple design. They wind their own transformers and utilize a more complex circuit design. You could understand it all, but it is beyond my humble comprehension. Finally remembered the one I had in mind. The Wolcott tube amps. Instrumentation amp design. I think it has SNR of 100 db, and distortion like .0001% or some such. Was pretty powerful too at about 220 wpc. Used feed-forward as well as feedback. Reading translated article about the Qualiton 50i it looks to be fairly conventional push-pull tube amp design done to a high quality level. I've had VTLs which were in the high 70 db range for 1 watt which put them near 90 db SNR for full rated power. So sure its possible. And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. Link to comment
jabbr Posted July 4, 2017 Share Posted July 4, 2017 Woah! Speaking of noise-- hot off the press: https://arxiv.org/pdf/1501.00195.pdf, http://ws680.nist.gov/publication/get_pdf.cfm?pub_id=901450 Kelvin is being tossed for SI: temperature now quantum noise measurement of a 200 Ohm resistor ... I wonder if a single electron clapping in the forest makes a sound ? Custom room treatments for headphone users. Link to comment
mansr Posted July 4, 2017 Share Posted July 4, 2017 12 hours ago, Ralf11 said: well, do you accept his stmt. that every component (even passive ones, and even resistors) has a non-linearity? Yes, at a very low level. 12 hours ago, Ralf11 said: and further, that those non-linearities can be heard when listening to music? No, not with components of reasonable quality in a competent design. sarvsa 1 Link to comment
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