John Curl's Blowtorch preamplifier part II - Page 3101 - diyAudio
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Old 7th December 2012, 01:58 AM   #31001
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Looks great, did-you have a photo of it somewhere ? Are they in Plastic ?
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Old 7th December 2012, 02:04 AM   #31002
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What is the product, Wayne?
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Old 7th December 2012, 02:13 AM   #31003
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Christophe,
The enclosure and the waveguides are all molded in polyurethane structural foam. Thick walled and very well damped. I had my own molding company set up at the time that I did that. I had a very large molding press and specialized Reaction Injection Molding machine which I still have in mothballs in storage. One of my specialties is plastic mold design and materials application. I spent 20 plus years doing product development and materials application. I was molding composite parts that were up to 4'x 7' and demolding them in less than two minutes. This development is what GM used later to produce the pickup truck beds on some trucks for a few years. I also did that for some solid fuel rocket development. I did a lot of first but like John I only seemed to make my customers rich while I did all the work. I closed down my operation and went into aerospace and now I am back at the audio development that I always was doing when I had the time.
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Old 7th December 2012, 02:29 AM   #31004
Jay is offline Jay  Indonesia
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Originally Posted by BV View Post
Blind test have nothing to do with "I like it ,or not "..They should discover really audible differences. If blind test show, that someone cannot distinguish two or more audio components by ear , it have no sense to talk about diferences in sound. That´s simple.
My point was, there are things that you cannot unleashed in a short-period blind test. How about people who cannot listen well. Do you think they should stick with LM1875 just because they cannot hear the difference with Aleph J for example? How lucky they are...

One important thing that I try to observe from a sound is musicality or fatigue or whatever that should be but related to my objective in listening to music, which is enjoyment.

A good system to me, is that sound that will keep me awake. I will stay up late, even didn't want to go to work. My wife will complaint because I stayed all day in the room listening to music. I like a system that will display who is the best singer, who are the top musicians, who are the best pianists, etc...

An average system to me, usually an over-engineered system, is those who is the same whether it is there playing music or not. I can go on reading book or do other things and forget about what is playing on my system. I only remember that the music was there when the CD reached the end of the last song.

A bad system to me, is that sound that I don't want to hear. Often time will tell if I feel disturbed with the sound. The best test is when I want to go to sleep or during my sleep where the music is playing. Many times I have to jump out of the bed to turn off the music.

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And differences in sound must be acompanied with differences in signal , other way it is black magic and alchemy..
So to summarize, 2 test questions for you are (1) Are you sure that when you cannot hear difference in a one minute blind test then there will be no difference whether you hear it in one month or one year? (2) Can you explain anything about how fatigue, TIM/PIM or anything works, and how they can be measured if you think they are relevant.

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Science has absolutely touched on a very large and significant part of audio. To state otherwise is incorrect.
Exaggerating or not, incorrect or not, I guess it depends on both psychological issue and hold your breath, science. To me it's just words contains information/message that will be lost if stated otherwise.

There are differences between those who think mostly with their "left brain" and those with their "right brain" (Please don't debate on the biology issue).

And you know what, musics and arts are usually associated with right brain. Those who can better appreciate tiny differences, such as emotion contents of a voice or face, body language, tone, I believe are those who have their right brain well developed.

Observe the famous "proverb": "The more you know, the less you understand". People like you may probably stand up quickly with objection. Your left brain says: "If nothing I know, nothing I can understand!" Good logic.

Some people OTOH, may find a "truth" behind above proverb. I have experienced the same thing, but not in electronics. I know almost anything related to the subject but then I feel I don't know or don't understand anything. The reason is because I found that those BIG knowledge database didn't reach the surface of the real issue. People with less knowledge OTOH may think they found the secret, may feel like a great scientist.

And in technical forum like this, you will always find some people who think and feel that they will look smart when they fight against things regarded as voodoo and non-sense. Basic psychology.

Last edited by Jay; 7th December 2012 at 02:32 AM.
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Old 7th December 2012, 03:24 AM   #31005
fas42 is offline fas42  Australia
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Quote:
Originally Posted by Jay View Post
A good system to me, is that sound that will keep me awake. I will stay up late, even didn't want to go to work. My wife will complaint because I stayed all day in the room listening to music. I like a system that will display who is the best singer, who are the top musicians, who are the best pianists, etc...

An average system to me, usually an over-engineered system, is those who is the same whether it is there playing music or not. I can go on reading book or do other things and forget about what is playing on my system. I only remember that the music was there when the CD reached the end of the last song.

A bad system to me, is that sound that I don't want to hear. Often time will tell if I feel disturbed with the sound. The best test is when I want to go to sleep or during my sleep where the music is playing. Many times I have to jump out of the bed to turn off the music.
The problem, Jay, is that I've found that a setup can go from that bad system to the good, as you've described them, and back again, so very easily; the slightest problem will drag down the good to the bad in a twinkling of an eye. Which is why a lot of people make do with your average, a lot safer and more predictable; it's living on the edge for me, keeping the head of a "goodie" above water -- may the force be with me ...

Frank
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Old 7th December 2012, 03:26 AM   #31006
wayne is offline wayne  United States
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What is the product, Wayne?
Solid state phono Perseus. Magico Q7 is overall product.
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Old 7th December 2012, 03:45 AM   #31007
Jay is offline Jay  Indonesia
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Originally Posted by fas42 View Post
The problem, Jay, is that I've found that a setup can go from that bad system to the good, as you've described them, and back again, so very easily; the slightest problem will drag down the good to the bad in a twinkling of an eye. Which is why a lot of people make do with your average, a lot safer and more predictable; it's living on the edge for me, keeping the head of a "goodie" above water -- may the force be with me ...

Frank
Yes, correct. It was the hardest part to learn (understanding the weakest link). My last lesson was about tube heater supply regulation. It was hard for me to accept tube "distortion" until I found out that tube heater regulation can easily become a bottleneck/weakest link.

Luckily I know more about speakers than amps. It is the "heart" of any audio system. Speakermen know more about good system than ampmen I believe.
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Old 7th December 2012, 03:57 AM   #31008
fas42 is offline fas42  Australia
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Quote:
Originally Posted by Jay View Post
It was the hardest part to learn (understanding the weakest link). My last lesson was about tube heater supply regulation. It was hard for me to accept tube "distortion" until I found out that tube heater regulation can easily become a bottleneck/weakest link.

Luckily I know more about speakers than amps. It is the "heart" of any audio system. Speakermen know more about good system than ampmen I believe.
Well called. The weakest link is where it's at, and one must make no assumptions, whatsoever, about where that can be.

I'm not proud: I call myself a systemman, I have no favourites amongst the gear; whatever's dragging the chain is part of the Evil Empire as far as I'm concerned ...

Frank
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Old 7th December 2012, 04:04 AM   #31009
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But we are on the way and we know, at least, when two signals are identical in a decent frequency range around audio range: 10 to 100 Mhz.
Harmonic distortion, Fourrier analyses, Intermodulation analyses, phases and delays (group delay, phase modulation) etc...
Not these approaches.
In your later post, you have mentioned direct error extraction between output and proper time shifted input, two voltages at a given time moment. If somebody will manage to achieve -160dB accuracy in this way (like Ed Simon did with resistors measurements), this will be real advance in applied sound reproduction studies. Why -160dB ? Resistors are quite listenable, but their measurable artefacts are around -160dB only. Similar numbers, I guess, are associated with capacitors, contacts, wiring, etc.
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Old 7th December 2012, 06:11 AM   #31010
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Why -160dB ? Resistors are quite listenable, but their measurable artefacts are around -160dB only. Similar numbers, I guess, are associated with capacitors, contacts, wiring, etc.
Well, the maximum level our ears are able to afford is 120dB spl. Where do you put those 'quite listenable' -40dB ?
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