John Curl's Blowtorch preamplifier part III

Status
Not open for further replies.
Jump to Latest
Tournesol

Tournesol

Member
Joined 2017
Max Headroom said:
You could start with clipping ferrite filters around each end of an RCA or 3.5 interconnect cable......use the shoe lace kind that come standard with most gear, you know the ones I mean. You can listen live to this difference by performing AB comparisons on the fly and you can also record these two system states/sounds or you can fit the ferrite filters around a loopback cable and record this changed system state for later audition and analysis. Once you hear and have learned the ferrite signature you will recognise it reliably in ABX and know it is no delusion.
Click to expand...
Sorry Dan. I still have ferrites on all my cables. Because i was, in my previous location, exposed to high RFI and found it worked for video.

Took the time to listen to any difference. Found nothing. Took the time to make measurements with my poor equipment that do not goes high enough in high frequencies, but is ok for audio. Found no difference, even in the phases at 40 000.

I don't exclude that i'm not trained enough to recognize, the "face in the crowd" that you seems to be able to. Or is-it my old ears ?

As I am able to immediately feel the difference, using my equalizer (i'm trained to), you will understand i will keep this way.
But, who knows ? I will make the comparison again in next days, focusing differently.

BTW: My line cables are CAT6 Sftp. As short as possible. My plugs mini XLRs preamp side.
 
Tournesol

Tournesol

Member
Joined 2017
Jakob2 said:
So, wouldn't it be great, if we could settle (at least) the dispute about Oohashi (high frequency detection by intermodulation) ?
Click to expand...
We're not out of the woods!
Reading a few pages about it, I had more questions going out than entering. Especially on the validity and even the interest of all these ABX listening tests which do not lead to any conclusion.

Jakob2 said:
Actually i was moved being promoted from the "know nothing categoy" to the next higher level.........
Click to expand...
Welcome in the club, jakob. Do you like a drink ?
 
E

Evenharmonics

Member
Joined 2007
Jakob2 said:
"transparency" (although not a general engineering term) wrt measurement would mean, that (beside the designed manipulation of an input signal like change of level) no difference exists between input and output signal.

Wrt reproduction of sound, the term "transparency" means that insertion of a certain kind of gear in a chain does not lead to an audible difference, so correctly it should be "auditory transparency" .
Click to expand...
So far so good.
So it gets a bit complicated due to the relation to human perception. Not detectable by average listener, not detectable by a specific listener, not detectable by _any_ human?

The goal for the reproduction of sound isn´t that well defined (or agreed by all parties) as PMA seems to state.
His version of the goal is an arbitrarily choosen reference point, which is not well defined - as it relates to the recorded content, that we don´t know - which must be reproduced by a system that by definition is declared as neutral if it is linear.

An approach that might be correct for some recordings, will be totally off for others - for all the reasons we have already discussed broadly in this and other threads - and does not reflect the point of view that you've mentioned, i.e. that basically the sound at the production facility will be the best reference for this theory about reproduction of sound.
Click to expand...
Unless your approach is identical to T's on this matter, the definition of hi-fi explains this. "Hi"(high) part refers to the level, "fi" (fidelity) refers to the faithfulness. Hi-fi, mid-fi and lo-fi would be subjected to the listener's experience and listening ability. One man's hi-fi may be another man's mid-fi or vice versa.

And it does not reflect that there is another school of thought where the reproduction should evoke a listening impression as similar as possible to the perception a listener would have had when attending the original event.
Click to expand...
That would be a task for recording / mastering engineer.
Jakob2 said:
we share the discomfort about the strange fact that a lot of these discussions are running in circles (sometimes over years, even decades).
Click to expand...
It sure does go around in circles because some either forget or intentionally discard what was already explained.
 
J

Jakob2

Member
Joined 2004
Tournesol said:
We're not out of the woods!
Reading a few pages about it, I had more questions going out than entering. Especially on the validity and even the interest of all these ABX listening tests which do not lead to any conclusion.
Click to expand...

Have you read Oohashi et al's publication from 2000?

https://www.physiology.org/doi/full/10.1152/jn.2000.83.6.3548

Still an interesting read and this kind of experiments nearly always raises (legitimate) questions, but PMA asserted that another experiment has shown Oohashi´s results were due to intermdolation effects.
I questioned the assertion (for various reasons, laid out in the post linked today) and hope for some final agreement on this subtopic.

But Oohahsi et al. didn't use ABX tests.
 
J

johnego

Member
Joined 2017
Evenharmonics said:
I've heard of different speakers for different music but amplifier? What models and brands of amps do you know of that are made for different music?
Click to expand...

I build my own amps so I'm not familiar with high quality commercial amplifiers for reference. But I think I can make generalization that class A on one side and class B (or may be class D) on the other side. Class A for vocal or simple music, class B for rock or when details can make music more impressive.
 
gpapag

gpapag

Member
Joined 2002
Paid Member
PMA said:
I would rather like to follow my previous post and bring some evidence. The test signal is a narrow-band noise (1000Hz - 1300Hz) which is unaffected in one file and the 2nd file has a special low-level distortion, spectrum of which may be seen in the attached image. If the test is performed on the pure sine, the files are indistinguishable. Tested on narrow band noise the difference is clear. Link to files below, this time no ABX is requested.
http://pmacura.cz/noise_test.zip
Click to expand...

I can not hear differences in files presented here and I don’t comment on perception issues.
But these two files is an exception, I clearly hear differences.
I couldn’t imagine that the kind of distortion shown in the 1kHz screenshot can have such pronounced effect (aural and on FFT) on the 1kHz to 1.3khz noise.
Thanks Pavel for the info and test file.

George
 

Attachments

  • FFT.png
    FFT.png
    73.1 KB · Views: 215
gpauk

gpauk

Member
Joined 2016
Paid Member
PMA said:
I would rather like to follow my previous post and bring some evidence. The test signal is a narrow-band noise (1000Hz - 1300Hz) which is unaffected in one file and the 2nd file has a special low-level distortion, spectrum of which may be seen in the attached image. If the test is performed on the pure sine, the files are indistinguishable. Tested on narrow band noise the difference is clear. Link to files below, this time no ABX is requested.

http://pmacura.cz/noise_test.zip
Click to expand...

That's fascinating.... Big difference! Thanks....
 
Status
Not open for further replies.
Top Bottom