Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

The Lounge A place to talk about almost anything but politics and religion.

John Curl's Blowtorch preamplifier part II
John Curl's Blowtorch preamplifier part II
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 21st July 2010, 04:25 PM   #4991
abraxalito is offline abraxalito  United Kingdom
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Send a message via Yahoo to abraxalito
Quote:
Originally Posted by simon7000 View Post
As all converters use analog input and output it is important to note that there are more issues than "is the analog as good as the digital?" When you charge a capacitor from a voltage source through a resistance the curve is an inverted exponential curve. Same for your current limited inductor, but of course you rarely see them in modern low level filters. So when you use a low pass filter to clean up your step jumps it is not a true linear average.
Where are you going with this - in what sense is the output of a low pass filter not a 'true linear average' ? Because the settling to the zero order hold DAC output is exponential so the target voltage is never in fact reached, or for some other reason? Are you suggesting there's an inherent non-linearity here?

Quote:
This also is why timing errors are of greater importance than it would seem at first glance.
Please do flesh out the relationship of DAC setttling time to timing errors if you can, its something that's been a bit of a fuzzy area for me for a while.
__________________
'The total potential here must be nothing less than astronomical.'
'Nothing less. The number 10 raised almost literally to the power of infinity.'
  Reply With Quote
Old 21st July 2010, 05:36 PM   #4992
Rod Coleman is offline Rod Coleman  United Kingdom
работник
diyAudio Member
 
Rod Coleman's Avatar
 
Join Date: Jul 2004
Location: Warwickshire UK
John Curl's Blowtorch preamplifier part II
Quote:
Originally Posted by SY View Post
Again, you've avoided the question of the bias signal on the analog tapes of recordings that you have found satisfying.

The effects of dither on resolution of a CD were clearly shown in the Stereophile review I posted (along with almost all of their other CD player reviews). FAR better performance when it comes to resolution than excellent analog systems. And the Lavry link that Terry so kindly posted. But most of all, the Lipshitz papers, which no-one besides me seems to have bothered to read.

I'm reminded of Max Planck's famous dictum:

"A new scientific truth does not triumph by convincing its opponents and making them see the light, but because the its opponents eventually die, and a new generation grows up that is familiar with it.

When you have some data showing the audibility of a 16/44 A/D-D/A inserted into an analog signal chain, I'll be most interested to see that.
SY, you're confusing the debate. I called dithering a second-rate solution compared to proper high resolution recording. In no place did I say that dithering wasn't clever, nor that it might fail to improve CD-format recording. But as Terry's evidence shows, the mechanism is programme dependent - Dithering is not the same as high resolution.

For the other question of LP vs 16/44.1, I have compared analogue LPs to 16/44.1 in one repeatable fashion: Digitally recorded & mastered LPs. I have hundreds of these (they're very cheap, and often have interesting pieces on them). Many are EMI pressings manufactured in the same plant as the last of the analogue versions. I do listening tests with a second opinion (first in weighting) - one of the longest serving sopranos at Armonico:

Armonico Consort - Home

She is completely uninterested in records, hifi or the like - she's a acoustic performer. But when I play digital LPs, she has consistently ranked them at the bottom, mostly due to a lack of life or vibrancy; and though the standard of analogue LPs is not at all even, they usually show a realism that convinces her, and me. Yes, we have experimented with SRA & VTA on these LPs, and will often return to within 0.5mm of the arm position she preferred previously.

Whether these faults in these records are down to word size, sampling rate or something else, I don't know. But the effect is not subtle, and I would not believe that tinkering around the edges will be enough to put it right.

CD shows a lot of the same traits to me. I know that the players are flawed, and can be improved greatly, but what I would really be interested in comparing is 16/44.1 against real high resolution - how high do you need to go before you stop hearing improvement?
  Reply With Quote
Old 21st July 2010, 06:06 PM   #4993
SY is offline SY  United States
On Hiatus
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
John Curl's Blowtorch preamplifier part II
Anecdotes of uncontrolled tests with poor validity aren't exactly data.

And PLEASE read the Lipshitz papers. You keep repeating the same incorrect statement regarding resolution. If you're just interested in mantras, that's fine- just man up and say, "My mind is made up and I don't really want to understand the issue." Nothing wrong with that and it's certainly more honest. But saying something wrong again and again does not make it right.
__________________
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote
Old 21st July 2010, 06:17 PM   #4994
Rod Coleman is offline Rod Coleman  United Kingdom
работник
diyAudio Member
 
Rod Coleman's Avatar
 
Join Date: Jul 2004
Location: Warwickshire UK
John Curl's Blowtorch preamplifier part II
Quote:
Originally Posted by SY View Post
Anecdotes of uncontrolled tests with poor validity aren't exactly data.

And PLEASE read the Lipshitz papers. You keep repeating the same incorrect statement regarding resolution. If you're just interested in mantras, that's fine- just man up and say, "My mind is made up and I don't really want to understand the issue." Nothing wrong with that and it's certainly more honest. But saying something wrong again and again does not make it right.
Reports of real listening may not constitute DATA but are no less real for all of that.

I am not repeating anything!! Perhaps you should clarify what you think Dithered 16/44.1 is actually equivalent to in resolution terms, so that we can debate the same thing, not confused nonsense.
  Reply With Quote
Old 21st July 2010, 06:22 PM   #4995
john curl is offline john curl  United States
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
Right on, Rod! Hearing is believing. Dr. Lipshitz disregarded MY measurements and mathematics regarding capacitor DA, because he thinks that very little really matters. So much for mathematical 'proofs'.
__________________
"Condemnation without Examination is Prejudice"
  Reply With Quote
Old 21st July 2010, 06:27 PM   #4996
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: The great city of Turnhout, BE
I am only aware of one test where a 16/44 A/D-D/A unit was inserted (or not) in a playback chain with an effort at test control. That was where Ivor Tiefenbrunn of Linn fame IIRC failed to hear it.

One test participant (who happened to be Lipshitz) WAS able to reliably identify the unit because after some time he realised that there was a slight difference in background noise with or without the digital set.

But those who listened to the music only could not identify what was what.
The test is documented on the Boston Audio Society (BAS) website, look under archive I think.

jd
__________________
Advertising is the rattling of a stick inside a swill bucket - George Orwell
Get more Linear Audio for less! Check out my Autoranger and SilentSwitcher
  Reply With Quote
Old 21st July 2010, 06:28 PM   #4997
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: The great city of Turnhout, BE
Quote:
Originally Posted by Rod Coleman View Post
Reports of real listening may not constitute DATA but are no less real for all of that.[snip].
Correct, but that 'data' is only valid for that person, that situation, that equipment, his mood etc. It's worthless for anyone else.

Come to think of it, it is worse than worthless, because it biases people to a certain outcome for their own listening.

jd
__________________
Advertising is the rattling of a stick inside a swill bucket - George Orwell
Get more Linear Audio for less! Check out my Autoranger and SilentSwitcher
  Reply With Quote
Old 21st July 2010, 06:31 PM   #4998
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: The great city of Turnhout, BE
Quote:
Originally Posted by john curl View Post
Right on, Rod! Hearing is believing. Dr. Lipshitz disregarded MY measurements and mathematics regarding capacitor DA, because he thinks that very little really matters. So much for mathematical 'proofs'.
John,

I don't think he disregarded your measurements and mathematics as such, he only didn't believe the effects were audible, which was an unfounded assumption anyway.

jd
__________________
Advertising is the rattling of a stick inside a swill bucket - George Orwell
Get more Linear Audio for less! Check out my Autoranger and SilentSwitcher
  Reply With Quote
Old 21st July 2010, 06:35 PM   #4999
jcx is offline jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
nobody is actually literally recording 16/44.1 today - oversampling, "24 bit" ADC and signal processing are much cheaper than 20 KHz analog anti-alias filters

broadband S/N >110 dB and differential linearity way down in the noise is the norm for top monlithic audio ADC

target rate brickwall filtering, decimation and bit depth reduction with dither is only used at the final stage of the production process


people should also ckeck out Lukin's dither clips - he provides 8 bit audio clips to exagerate quantization noise artifacts and show various dither's improvement in audible resolution and noise shaping's reduction in dither noise perception

Homepage of Alexey Lukin
  Reply With Quote
Old 21st July 2010, 06:36 PM   #5000
john curl is offline john curl  United States
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
[snip]
I have always believed [snip]

Fine!

jd
__________________
"Condemnation without Examination is Prejudice"

Last edited by jan.didden; 21st July 2010 at 07:04 PM.
  Reply With Quote

Reply


John Curl's Blowtorch preamplifier part IIHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


New To Site? Need Help?

All times are GMT. The time now is 10:06 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki