John Curl's Blowtorch preamplifier part II

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so this provides the loop de loophole for 2 sets of bitperfect data sounding different, simply because the 2 playback systems, even the same one and the same file, played back at 2 different passages of time.

the offending modern playback systems apparently have the worst PSRR known to man.
Everything can have an impact, and unfortunately, very unfortunately, things like this can be the difference between 'great Hi-Fi' and something that sounds 'real' ...
 
The affects are not limited to just limiting and dynamic range but adds real distortion (Harmonic and IM) amount depending on method used.

Thx-RNMarsh
I would dispute that -- just yesterday I listened to a borrowed CD, "Now The Hits of Spring 2010" on the UULE, the cheapie TV setup - yes, you can imagine what some of the material as music was like - but I didn't hear distortion. Very LOUD, so had to turn the volume down quite a bit, but good integrity to essentially all the material. In fact, if the system had decent bass and a smidgeon more quality some of the tracks would have sounded very, very impressive ...
 
What SY was mentioning is being able to hear a difference in the final audio from flipping over a fuse. A much tougher issue as there is a bit of difference but that is only in the millivolt range.
Hmmm, let's see ... millivolt range is roughly around 60dB down from peaks in power amp output, but apparently will be inaudible. High quality MP3 encoding is a form of distortion, because the output is different from the input, but with much material the difference is, surprise, surprise, around 60dB down from the peak, compared to the 'pure' original ...

Now, everyone "knows" MP3 sounds dreadful, unlistenable to on a decent replay setup -- hmmm, something doesn't quite gell here, might have to go away and scratch my head a bit ... or, horror of horrors, collect some data ... ;)
 
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I would dispute that -- just yesterday I listened to a borrowed CD, "Now The Hits of Spring 2010" on the UULE, the cheapie TV setup - yes, you can imagine what some of the material as music was like - but I didn't hear distortion. Very LOUD, so had to turn the volume down quite a bit, but good integrity to essentially all the material. In fact, if the system had decent bass and a smidgeon more quality some of the tracks would have sounded very, very impressive ...

I am not sure what that disputes, actually.

-RM
 
Yes. There is no arguing that point. Others can try but I cannot be convinced otherwise. Going off on a tangent about bit error correction for CD's et al is just a smoke-screen as far as i am concerned. The issue is still why LP and CD do not sound like the original master tape recording. There have been a few replies that are accurate about this but not down to any hardware/software specific that we can go after. So, I surmise from experience that a big sound changer occures when compression and limiters are used. And they are mainstream in useage.
and I might include compression codec's in here too.

Thx-RNMarsh
Hello Rodney, in the case I described, no compression or limiting was used in the Tape/CD comparison.
In this example, the multi-track tape played back through a studio desk in mixdown mode, with the resultant stereo signal sent to monitors, and also sent to a (Tascam maybe ?) self contained CDR machine.
The monitors were switchable between the desk output and the CDR machine playback output..ie by flipping a switch, it was possible to compare the two playback signals.
In this case, the newly recorded (burned) CD sounded flat and lacking in detail and presence and HF 'air' when compared to the 15ips tape playback.

Dan.
 
No Blind ABX Required....

Nah, just a bunch of pro audio guys lamenting "this is whats on tape", and "this is what the music buyer gets".
The differences were not catastrophic, but most certainly noticeable.
So, experienced and practiced ears doing a sighted comparison listening test, as is perfectly normal and valid in music production circles....and all ears in agreement.

Dan.
 
I am not sure what that disputes, actually.

-RM
Disputing that the studio fiddling "adds real distortion (Harmonic and IM) amount depending on method used" - yes, sometimes a very clear attempt to produce an effect will add a distorted quality to the sound, but that distortion is part of the effect.

The compression and limiting of dynamics make it hard work for many systems to reproduce cleanly - but that's the fault of the replay chain ...
 
To truly understand what is affecting what, apples need to compared to apples, oranges need to compared to oranges ...

If comparing different versions of digital with each other they need to pass through the same decoding to analogue, to sound path ...

If comparing analogue to analogue, where the second version is a copy of the first which has gone through a further set of electronics, and is being replayed from a completely different source mechanism, then as far as I'm concerned nothing can be concluded from this, except that they will sound different, and it's almost guaranteed the second version will sound worse ...
 
Thats good. Did you get to run any tests thru the sytem... like freq response or distortion etc to help determine why you heard a big difference? or help determine what was Not the reason?
Thx-RNMarsh

Level matching. Very accurate description of the subjective reaction to a few tenths of a dB difference. People rarely take care to accurately level-match.
 
At the fundamental levels of the physical universe everything does, of course, but we won't worry about that, ;) - but, it's a modus operandi which I find very fruitful, hence I'm happy to live with some of the 'impossibilities' ... :)

Where the interesting area lies is in what one takes "insignificant" to mean- it obviously varies per individual, and set of ears, but I take it be meaningful in respect of whether I can perceive an audible variation, rather than measurement by test device.

Unfortunately for me, I have heard differences occur what from most would consider bizarre variations, seemingly irrelevant changes in the environment - so until I can convinced myself otherwise, by experimenting, everything is fair game ...
 
thats the problem Frank, too many come at this from a philosophical direction. some, like yourself, try to make everything blurry, mysterious and organic. these objects are not people, they are not organic and they are not connected to your ears.

its interesting that in such a topsy turvy, screwed up world where perfect and near perfect systems and objects are dysfunctional and imbued with personality, the ears and mind are often considered such amazingly accurate and infallable instruments...
 
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all the electronics are connected, even if the linkage is mainly RF in nature. Unless everything is battery powered, the linkage extends back via the mains power commonality.
And how is the linkage RF?
As to the second statement, a battery is a power source, no more, so unless the digital and analogue is galvonicly isolated they are still connected.
I don't know how much digital/analogue design you are involved in but I do think the coupling is a bit over exaggerated and the noise levels, for well designed equipment it isn't such a bad problem as I think some see, and here I am talking phase array radar (50 channel ADC), medical equipment, military gear. But the point is well designed analogue/digital designs, a lot of audio isn't either due to cost for commercial or fashion for DIY.
 
sure Chris, they never do; I just felt the irony was worth mentioning ;)

anthropomorphism, like that word, don't often get to use a word like that :) but whats the reverse of it in this context?, it seems we have both existing side by side here. perhaps psychomorphism, or abiogenesis? anyone got a word for thinking you are cybernetic?
 
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thats the problem Frank, too many come at this from a philosophical direction. some, like yourself, try to make everything blurry, mysterious and organic. these objects are not people, they are not organic and they are not connected to your ears.
The philosophy is used to direct how I go about seeking a solution to SQ, rather than towards the components themselves - they just boring, semi-crappy bits of electricals and electronics, which behave according to what happens in their environment. Which includes the properties of the materials that parts are made of, as well as their nominal electrical characteristics - I can mention the word 'tempco' without people here having a mental overload, I just extend it a bit further and assume there are 'xxxxcos' all over the place, the vast majority which will be microscopic or harmless - but there will be the odd one or two that cause audible problems ...

The ear and mind are not infallible, but they are extremely sensitive to unexpected or abnormal variation - the sort of thing that makes a person snap to attention in bed, from 'sleep', when a noise that 'shouldn't be there' is heard. For me, low level distortion does that in spades - I'm not interested in reading the opinions of an 'expert' that it's all in my mind, especially when I can switch the artifact on and off, consistently, any number of times - say, to satisfy a PHD craving researcher ... ;)
 
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