John Curl's Blowtorch preamplifier

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The system used for evaluation is an unavoidable part of the process. I used to own an all Denon system some years back, good stuff, my first attempt at a "high end" system. I own a Stereophile test record, one of the tests was a music piece recorded in both 14 bit and 16 bit resolutions. I wanted very badly to hear the improvement of the 16 bit version (for me at the time that Denon stuff was real money), but I couldn't.

Many years and dollars later with Levinson and C-J equipment and better speakers the 16 bit version was revealed as being less coarse overall. The difference was audible, but hardly stupendous.

My point is that only the very finest systems are capable of revealing the small subtle differences between say for example 0.01% distortion and 0.001% distortion.

If I were asked to listen to the difference between a CD and an SACD on that Denon system, I would proclaim with certainty that there wasn't any. I now know that many factors control the end result and do try hard to shy way from absolutes.

By knowing how they work, tests can be (and have been) devised to show the difference between Redbook PCM and DSD as used in the SACD format. The big problem is correlating the test results with what we hear and what we like.
 
"What we have here is a failure to communicate" Some here actually believe that ABX testing will separate what is truly audible from what only appears to be audible. We have been at this for 30 years. Unfortunately, ABX testing tends to merge subtle differences beyond frequency response and a certain significant distortion threshold (like clipping) into confusion.
Peer review, who cares, IF the differences are merged by the test itself to revealing no differences?
Great documentation PMA.
 
PMA said:
IMHO in the best way possible. Same player, same D/A converter, no change in cables compared to standard listening conditions, just switch between 16/44.1, 24/96, 24/192 tracks. Same volume level. Same recording equipment. Anything wrong here? (I speak about resolution project disc).

Nice test data Pavel. I think that Philips makes an SACD processor chip that converts the SACD DSD to PWM 24/96 for cheap consumer universal players. That might produce "same as" results that were being discussed. I have a Pioneer player with just such characteristics for the back room TV.
 
scott wurcer said:


I have a Sci-Fi comic from the 50's where the hero is a fedora wearing archeologist searching for lost Aztec gold. :bigeyes:

Wow!!! so the person who wrote that comic must have been a psychic... Sorta like he knew someday there would be a Dr. Jones, probably saw it in a vision, and was inspired enough to get it into print. Talk about double blind! It hadn't even happened yet!

Let Technology try to explain that one! Hmmmm.

I’m having a Nostradummass moment here… Ok, I’m better now.

Back to this intelligent discussion for people who need a room full of blind people to tell them what they are hearing.

There is no resolution to this crisis with words and I don't see what the point of this is.

Actually I do but it has nothing to do with solving anything. In a perfect world it would end, but this is the internet.

Have nice day🙂
 
Yeah!..............but what happebned to the Blowtorch?

Actually it surprises me you haven't build one yet, really.
Plenty of patented and well proctected schematics from everybody BUT the main man himself. Pathetic don't you think?

However we still have a few PCB's in stock, so don't hesitate and call the main man and hey..... be persistant 😀 ....he might give in within 30 years or so . . . . . . . . . :sigh:
 
Franklin,

I was concerned where this thread was heading......................the differences between SACD and CD's?

I have to admit Mr.Curl is a tough nut to crack but I have learn't a lot from him and so have a lot of us .......................😀 ,
I happen to be working on something with a similar topology, and if I ever were to post it you can be sure I will give credit where it is due.
Please see my threads on the other web site.:angel:

Jam
 
john curl said:
"What we have here is a failure to communicate" Some here actually believe that ABX testing will separate what is truly audible from what only appears to be audible. We have been at this for 30 years. Unfortunately, ABX testing tends to merge subtle differences beyond frequency response and a certain significant distortion threshold (like clipping) into confusion...........

I for one believe blind tests do that, and they also separate out 'real' differences by their magnitude.
The point at which the test results "tends to merge subtle differences" is determined by the ears, not some measuring gear that 'doesn't know what to look for'.

Hope this communicates something. 🙂
 
MikeBettinger said:
.....There is no resolution to this crisis with words............


Absolutely agree. I've said elsewhere, Blind tests are not all equal in methodology or subjects taking part, so there is no reason for anyone get unduly upset over the results. The results apply to that test, those people, on that day. You maybe different.

Find out your own threshold at home by doing some simple blind tests, after all this is DIY.
 
fredex said:



Absolutely agree. I've said elsewhere, Blind tests are not all equal in methodology or subjects taking part, so there is no reason for anyone get unduly upset over the results. The results apply to that test, those people, on that day. You maybe different.

Find out your own threshold at home by doing some simple blind tests, after all this is DIY.


Fredex,

If M&M came to your home town, did the same test, with local listeners, with the same outcome, wouldn't that increase the confidence that there is some objectivity to the outcome?

Jan Didden
 
janneman said:

Fredex,

If M&M came to your home town, did the same test, with local listeners, with the same outcome, wouldn't that increase the confidence that there is some objectivity to the outcome?

Jan Didden

Jan, yes it would. But there is nothing like your own experience. I thought DBTs must be flawed because I can hear amp differences as well as the next man, cables even! Then I did a simple blind test.
 
fredex said:


Jan, yes it would. But there is nothing like your own experience. I thought DBTs must be flawed because I can hear amp differences as well as the next man, cables even! Then I did a simple blind test.


If I may parafrase that: There's nothing so unreliable as your own (remembered) experience.

BTW, I think that is what M & M did. They took their show to many different places, diffierent listening crews.


Jan Didden
 
janneman said:



BTW, I think that is what M & M did. They took their show to many different places, diffierent listening crews.


Jan Didden


From the descriptions these folks also seemed to care about listening and were not all skeptics, even though I suspect EBM is.

Remember "blind" is only one aspect if you want to be "scientific". There's the elimination of other effects, which even comes to play in ABX. As I mentioned before it was EBM's ABX that was flawed at an AES meeting such that anyone could do 100% without even listening to the music.
 
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