John Curl's Blowtorch preamplifier part II

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On the AVS forum you'll be put on a cross if you believe DAC's sound different that have the same sample rate...

Digital filters, noise, clocks, etc, mean nothing to them.

Ah, social psychology is such an interesting subject. Why be put on a cross for that? Read Jonathan Haidt's book, The Righteous Mind, to find out.
 
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For reasons I do not understand I do not like the sound from the ESS DAC's I have used, but that was sighted. . .
May I ask what you didn't like about it? I ask because I built a few prototypes ESS DACS for a production run that never happened. I took one to RMAF and it got some interesting reactions.

Wondering what you heard that you found different from others.
 
On the flipside, there's a lot to be said that this thread has jumped off the rails about people complaining about things nominally < -100 dB of full scale output, and/or effective at frequencies nearing or succeeding 22.1 kHz. As the readership here is predominately >50 year old males, this is a bit troubling.

So throwing around a bunch of buzzwords without thinking about the problem more carefully leaves me with a bit of, um, incredulity as to most people's positions on the matter.
 
On the flipside, there's a lot to be said that this thread has jumped off the rails about people complaining about things nominally < -100 dB of full scale output, and/or effective at frequencies nearing or succeeding 22.1 kHz. As the readership here is predominately >50 year old males, this is a bit troubling.

So throwing around a bunch of buzzwords without thinking about the problem more carefully leaves me with a bit of, um, incredulity as to most people's positions on the matter.
These things eat away at the stereo spread. I'm 55 and can hear only to 13.5 khz on a good day. Even well mastered digital sourced LP's kick me in the face with soft top end. Forum member Mooly once posted some sound files. I spotted the lower bit rate one in an instant even through the WWW and my so-so computer speakers. So the age thing hasn't made me able to listen, not hear or not care.
 
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On the flipside, there's a lot to be said that this thread has jumped off the rails about people complaining about things nominally < -100 dB of full scale output, and/or effective at frequencies nearing or succeeding 22.1 kHz. As the readership here is predominately >50 year old males, this is a bit troubling.

Perhaps not everything detected as a sound difference is due to THD below -100dB nor from music frequencies at 20KHz.

Do you think??

-RNM
 
That would make sense in an SPDIF world with changing data sources. USB async DAC's should be pretty immune since the clocks are fixed and the system is locked to them. However A/B'ing USB DACs really means stopping or rebooting the host processor.

Simple fix- add 250 mS of digital silence to the beginning of any tracks used for comparison testing?

My systems use a master clock. CDs are reclocked in a buffer so even they match. Very noticeable issues not using a master clock in my size rooms. A low noise oscillator is at the heart of the system.
 
Guys, you all were just a moment talking about clocks/jitter and filters as the magical difference between DACs, now we're all changing our tune. I really doubt many of you can hear the difference between two well engineered products using the same chipset but one with superb clock control versus "good" (here is our <100 dB effects) and the difference in filters which affect the response only in the highest of the passband (here's your old ears). I doubt I could and I still have quite good HF sensitivity.

I realize this thread is, to John's dismay, a water cooler topic, but there are a lot of poorly thought out opinions that are thrown around without a moment's passing as to their reasonableness. Or whether the assumptions made as to a position are built on the remotest of firm ground.
 
I rarely hear what I consider 'really good' digital reproduction. Of course, I listen to digital all day and 1/2 the night through cable TV and FM radio, but then does listening to a politician rave (as I am doing at the moment) really call for ultra high fidelity? I don't think so.
However, when I try to listen to the best digital that I can justify, I am always let down. I would have to pay many thousands of dollars for better digital reproduction, and I just can't justify it. I do have an OPPO 105 that works OK, but just OK. I also have several tweaks and mods like a super CD, SACD cleaner system that I am willing to try. I do hope it will help, but it will require more effort to implement than I am willing to put in at the moment. I wish I could just be happy with SY's CD playback, it would be so much easier. I DO have the CD's, I just don't like the sound of them.
 
Guys, you all were just a moment talking about clocks/jitter and filters as the magical difference between DACs, now we're all changing our tune.

We understand something is wrong, and that there is a problem. We don't know if it that people can hear more than previous studies suggest. If we can, there were probably issues with the experiments. It has happened in other fields. We also don't know if there are things we don't yet know how to measure, or that we need to measure, or that humans can hear, such as the recently discovered clock settling time effect.

Regarding what we do talk about, we talk about the things we know about now. How can we talk about things that are not yet understood at all?

Also, you show yourself to be biased in this matter by using the word "magical." If you were a scientist, you might be more interested in finding out what is actually going on, rather than using derisive terms.
 
You do not need to spend much to get SOTA USB DAC performance. These measurements are from a $60 USB DAC Xmos U8 DAC AK4490 Top Asynchronous USB Decoder Support Headphone Output | eBay With two mods- a 12V DC supply and swapped the socketed opamp for an LME49720. Not much of a challenge.

More could be had if someone wanted to make new firmware to support additional features supported by the AK4490.

(Both at 44.1 KHz sample rate and the distortion is possibly limited by the Emu 1616M.)


It is indeed a great buy and it measures very, very well. Actually, I swapped the socketed 5532 for a 4562 (same as what you did bar the type number) and saw distortion go up (ever so slightly). Did you measure before and after and did it go down in your case?

At any rate, as a signal generator, it is better than what is inside the EMU1616m, and the EMU is capable of picking up that difference (at least in my case). At 1kHz it is almost as good as Victor's.
 
How do you know he isn't a scientist?

He might be, but research suggests he does not have the optimal personality type to be the best at it. Scientists have to be able to defer judgement about things that are not fully understood. Also, both scientists and engineers have to remember that we use simplified models of reality to understand everything. For example, a single tone harmonic distortion hearing sensitivity test is a simplified model for hearing sensitivity of music which is far more complex. We don't fully know the limitations of that model. Or, consider that jneutron recently pointed out things about skin effect models and bessel functions that I never heard about before. A few years ago some people would have insisted that all the books on the subject have all the same formulas for calculating skin effect, we fully understand that, know it's true, anybody who says otherwise is engaged in magical thinking, etc. Reality isn't exactly the same as the models we use to represent it. We use the models because they reduce complexity to a level more manageable by human brains.
 
More generally, it seems not unlikely there are other things similar to this that have not yet been discovered or the effects of which are not well understood. My guess would be that over time we will learn more about how to measure some of the other stuff that some people report hearing. Not everything of course, some of it is surely imagined.

But already we have people here who report being able to hear difference between DACs with very good specs. I don't think they are all crazy. For people who don't hear a difference, its human nature for it to be hard to believe something you can't see or hear for yourself. On the other hand, also because of human nature, its easy to jump to a conclusion that other people are imagining things. All the more so if we are overconfident that science has already discovered all the answers and there is nothing more to learn.

I have no problem with this hypothesis (that people can hear differences between well performing DACs). The issue is that nobody is willing to prove this in a methodologically sound way. This should not be difficult given the audible differences that are reported.
 
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