John Curl's Blowtorch preamplifier part II

[Esperado]

I wonder of all the people who have commented how many have actually tried it ?
If you did, you might be pleasantly surprised

I. My system in Paris was done that way (3 cables). And i confirm it is perfect. But awful looking.
My original question was why so few hp cables are shielded (preventing EMI/RFI to return in the amp's feedback loop).
But some prefer to play with virgins, burning cables and liquid helium treatments of coper and Teflon.

 

[kgrlee]

Kgrlee, I spoke to Ron Quan about whether the CTC Blowtorch was a good candidate for measurement. He thought not, just like I presumed he would.

Is that cos Blowtorch would do worse than cheapo stuff on Ron's test?

Please let us know what he said.

What about your Hirata tests on Blowtorch?

Are you sure he was doing any Hirata test last Friday? My understanding was he was provoking others to make the test as their homework

JC has a Hirata test box. He pontificated at length about how important this is. It's unclear which of the 2 Hirata AES papers they test to. But he promised to carrry out the tests on Blowtorch last Fri.

After the weekend, he pontificated at length on why the unwashed masses (us) would not be able to properly interpret the results of a Hirata test.[*]

But he didn't attempt to enlighten us .... and didn't post his Hirata tests results on Blowtorch?


[*] In fact hinted that the test might be rubbish.

 

[jneutron]

It costs about $1 / meter and after a reasonable run in period they can sound pretty darn good.

I have never seen any reasonable explanation which supports run in of the wires. None.

I can support run in of the listener...been there, done that..

p.s. CAT6 sounds better that CAT5 so I would not bother with CAT5

I've also seen nothing to support that.

Not disagreeing per se, just haven't seen any explanation which would hold water..

cheers,

jn

 

[PMA]

Indeed. I said nothing about adding anything to the signal.

.

In fact we have to "subtract" (reduce, filter) interference noise. From power supplies, cable interconnects and EMI/RFI. This is not any addition, but cleaning.

 

[Kindhornman]

JN,
Now I understand what you are looking at. A modulated inductance caused by the moving voice-coil in the gap. This is one of the reasons that I use a very long gap with a short voice-coil as the voice-coil sees the same magnetic energy throughout its travel. One of the reasons in a cone loudspeaker I would never use an under-hung coil or an equal length coil and gap, both of these types of devices are nonlinear in design, no way around that factor. And another thing is that I do use a copper sleeve to smooth eddy currents in the magnetic motor. Many manufacturers talk about a shorting ring to smooth the eddy currents but it again is a non-linear design that they are using this way. Yes I do loose some efficiency this way but the decrease in distortion is much greater than the loss of power output. A friend independently tested my speakers and said they had the lowest distortion product of any cone device he has ever tested and he is also a loudspeaker designer and electronics wiz. His area of expertise is passive xo design and also compression driver designer. Now that I have entered the world of electronic circuit design I have now seen some of the things that he is doing used in the active xo area. They are starting to make much more sense to me. I couldn't understand how he was passively producing some of the slope and notch filter functions before, now I understand. Loudspeaker physics just seems so much simpler than the math involved here in electrical circuit design. I still remember that aha moment when I saw the math in trig with the square root of -1 and could understand what the hell a radian was and how it applied to audio design. I wish I could go back in time and know what I know now, I would have paid much more attention to why I was learning that stuff. Today I get to help my daughter with her algebra, that has been a trip. remembering all the things you think you will never have to do again.

 

[Joshua_G]

Hey, Joshua! What have you been ADDING to the audio signal? Can I have some? '-)

Hi John,
I did nothing that may add to the signal. As far as I can see, the sense of music realism has nothing to do with adding anything to the signal.

 

[jneutron]

Indeed. I said nothing about adding anything to the signal.

Concur. What adding was meant to convey was changing..modification. To me, the word transparent means to not alter in any fashion.

Systems which measure the same should sound the same. Unfortunately, bench measures are not in situ measures.

I didn't say and I didn't mean "ultimate soundstage or performance".
I spoke only of the sense of realism of the music.
I know that not many people are interested in it, I do.

I consider soundstage and performance (not artist, but system) to be realism. I want to close my eyes and touch the artist.

cheers, jn

 

[kgrlee]

I do build speakers from scratch from the frame to the cone and have my own motor design and I am wondering where that much variation is coming from? I know I test more than a single unit when I am looking at the electrical responses of my devices and I have never seen that kind of variation. .... The difference between the moving mass from one device to another is at most a couple of mg. per device at most.

Kindhornman, which company do you work for?

What kind of horn units are these with less than couple mg variation?
How do you measure the moving mass?

Ricardo "grovelling on his knees" Lee
_______________

I won't join in on the 'varying inductance & other stuff' on speakers other than to say Guru Kindhornman has some of the solutions (if not the answers ).

Also ACE & the papers I quoted on the subject have a lot that bear on it. Chase up the references in those papers too.

 

[Joshua_G]

Any system, has significant H2 ..... if not from funky electronics, then from speakers, themselves. No one has heard reproduced music... not the recording engineer, mixer, producer, musician without some H2 in it. With systems with very low levels of H2 are produced, people generally do not like it and think it is not musical or it is unnatural. Its as if you need to put back a little H2 to be accepted and i am sure this has been done deliberately in some equipment to make it more musical and less sterile. HOWEVER --

When you listen mostly to LIVE music ...without amplification and loudspeakers.... it does sound closer to the system which is serile. And, if the front end of the chain is recorded with very low distortion and no EQ ... it sounds best or more like Live sounds with a playback that also has very low distortion. Thx-RNMarsh

Hi Richard,
I go a lot to live classical music concerts.
I have no idea about the distortion level of my speakers, however, none of the electronic gear in my setup, in the past and in the present, had/have above 0.1% of THD.
So, it isn't high THD that gives me a better sense of music realism.
I didn't find that sterile sound gives better sense of music realism. Now, sterile has nothing to do with THD level. I tried various power amplifiers, all had very low THD, not all of them sounded the same.

 

[Esperado]

Are you sure he was doing any Hirata test last Friday?

That's what he said, if i remember well. Something like "I will do an Hirata test of my Blowtorsh next friday".
It is in the thread, black on white.

[edit] I have been asked to do a Hirata test. First, perhaps we should understand what the Hirata test is:
Test on Friday. '-)[/Edit]

 

[Esperado]

I consider soundstage and performance (not artist, but system) to be realism. I want to close my eyes and touch the artist.

I too, specially when the singer is a very pretty girl

 

[jneutron]

JN,
Now I understand what you are looking at. A modulated inductance caused by the moving voice-coil in the gap. This is one of the reasons that I use a very long gap with a short voice-coil as the voice-coil sees the same magnetic energy throughout its travel. One of the reasons in a cone loudspeaker I would never use an under-hung coil or an equal length coil and gap, both of these types of devices are nonlinear in design, no way around that factor. And another thing is that I do use a copper sleeve to smooth eddy currents in the magnetic motor.

Yes.

For static systems, the voltage at the terminals is e = L di/dt. For dynamic systems, the voltage is e = L di/dt + i dL/dt.

When a current is present in a moving VC, the iron or copper will fight change of flux (lenz effect), lowing inductance and increasing Rs. A moving VC will appear to have lower inductance because of this. How much, no clue..

THAT's where speaker designers come in...

jn

 

[PMA]

Though it may sound as a nonsense, we have to consider speaker cables as distributed parameters. For induced interference, at least.

 

[Joshua_G]

Did i wrote that ?
…

No, you didn't write it explicitly, however it is what I got from what you wrote.

I'm interested about what you call *realism* when i produced records.

Good to see it.
Is there any possible difference between what you call realism and between what I call realism?

And was payed for that ability and talent to create that kind of make believe. Dot.

Is music realism a make believe, to your view?

When it is about reproduction, i want fidelity. Carbon copy. Not at all the same thing.

What do you call "carbon copy", what do you call "music realism" and what's the difference between the two?

Possibly, you and me attach different meaning to certain words and expressions.

 

[Joshua_G]

Musicians comes one after the others in a more and more little studio, and engineers try to create a realistic make believe the where all playing together in a big hall stage.

To my view, this is adding some artifacts. It has nothing to do with actual music realism.

I have many recordings recorded at concert halls. No all of those recordings have the same amount of music realism. Thus, music realism isn't about artificial attempts at creating a sense of a concert hall.

 

[Joshua_G]

In fact we have to "subtract" (reduce, filter) interference noise. From power supplies, cable interconnects and EMI/RFI. This is not any addition, but cleaning.

Indeed, however we need to attempt at adding as little as possible and subtracting as little as possible to the audio signal itself. By adding as little as possible means not only THD and IMD.

 

[31697B]

AC line interference eliminated -

I decided to put my TEK scope with FFT option (FFT to 300MHz) on the thd analyzer residual output and there was a large freq at 305KHz. After some exploring for its source, it was coming from an iPOD Classic plugged into a speaker tower thingy that i use for background music in my testing room. It wasnt from the iPOD itself but the player/amp/spkr base. probably digital amp and/or power supply. It was the power supply -- when I put the distortion analyzer thru an ac power isolation-filter which i designed for Monster Products - it is now gone. Be careful to avoid EMI/RFI when testing, too. AC line interference gets into everything. THX-RNMarsh

 

[gpapag]

I have a Telefunken portable radio that I first bought in 1965, and used it, even today. I love it! Better than any Sony, etc I have ever tried.

JN,

…one of the reasons that I use a very long gap with a short voice-coil as the voice-coil sees the same magnetic energy throughout its travel. One of the reasons in a cone loudspeaker I would never use an under-hung coil or an equal length coil and gap, both of these types of devices are nonlinear in design, no way around that factor
.

Steven, please have a good look on pages 28 to 33 especially fig. 24,25,26 on Mr. Klippel’s paper.

OK George, AND?

Not OK. Did you read them that fast Mr. Curl? At least you should take note of IMD % figures on pages 46 to 64 of Mr. Klippel and I am afraid all pages of Ms. Thuras, Jenkins, O’Neil )

OR they are non relevant to "REAL WORLD Audio"?

George

 

[Esperado]

Is music realism a make believe, to your view?

Absolutely.
And the best ways to create this realistic make believe require often very unrealistic recording methods. Close miking, use of many effects and frequency corrections, artificial reverberations etc.

If you are talking about live recordings of classical music concerts with a couple of microphone, im' no more in concern, and i found never those recordings as "realists".
Because, when i'm in a concert hall, my brain do all his possible to get rid of ambiance of the hall and concentrate on the instruments i never hear close enough.

But our discussion was about digital equipment, and i was just pretending that you can have top transparent parts, using good consumer products, reclocking, filtering power supplies for no noise and using good DAC and good following analog stage, with no need of "Golden Pinnae" mysterious devices and transports.
Transparent, i mean no audible added distortion, no losses of details, no tonal change, no added sparkles. Nothing you can distinguish from an other similar device in a noticeable way with blind listening.
If one thing is reassuring, in the digital domain, it is that all is measurable (samples). I hoped we could, at least, get rid of all this cloudy voodoo audiophile magic.

But no. Some try to bring-it back ?

 

[Joshua_G]

Concur. What adding was meant to convey was changing..modification. To me, the word transparent means to not alter in any fashion.

An ideal recording/mixing setup and reproducing setup would be 100% transparent.
Practically, in our present universe, no recording/mixing setup and no reproducing setup is 100% transparent.
Therefore, the whole process of recording and the whole process of reproducing involve compromises.

Systems which measure the same should sound the same.

Ideally, it should be so.

Unfortunately, bench measures are not in situ measures.

Indeed. Therefore, at present, we cannot choose audio gear based on measurements alone.

I consider soundstage and performance (not artist, but system) to be realism. I want to close my eyes and touch the artist.

Soundstage performance is only one aspect of music realism.
Since I listen mostly to classical symphonic music, there is no way that in my tiny living room a soundstage the size of a concert hall will be reproduced.

There is no sound reproducing setup in the world, at any cost, that can reproduce live music with perfect fidelity. By perfect fidelity I mean that a trained professional musician, one who cares about the sound of the instrument one is playing, will enter a room with ones' eyes blindfolded, and will mistake a reproduced music to be a live concert.

Therefore, compromises are unavoidable. Some people don't care at all about any proximity to live concert. Out of those people who do care about it, to various people, various aspects of live music are more important. Hence personal taste and preferences.