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Old 4th December 2010, 07:50 AM   #3741
soongsc is offline soongsc  Taiwan
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It's well known in the industry that distortion figures may not be directly related to percieved sound quality. This is what George is trying to point out. So there must be some other aspect improved that relates with percieved sound quality. It's too bad that the method to find a relation between sound quality and measured data is not openly available. I personally only use single tone harmonics testing in the process of diagnosis, not the final judgement.
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Old 4th December 2010, 08:08 AM   #3742
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Related comments here...http://www.diyaudio.com/forums/analo...ml#post2386926

onesdx, you have not answered my question yet...
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Old 4th December 2010, 08:21 AM   #3743
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Originally Posted by soongsc View Post
It's well known in the industry that distortion figures may not be directly related to percieved sound quality.
This is just... untrue ! And George himself claims just the contrary... even for bad reasons !


Quote:
This is what George is trying to point out. So there must be some other aspect improved that relates with percieved sound quality. It's too bad that the method to find a relation between sound quality and measured data is not openly available. I personally only use single tone harmonics testing in the process of diagnosis, not the final judgement.
You're definitely not in agreement with what most of the professional audio engineers know for a long time ago now... Please, would you explain what means exactly your signature : "Hear the real thing!"

Last edited by ondesx; 4th December 2010 at 08:25 AM.
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Old 4th December 2010, 08:21 AM   #3744
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Quote:
Originally Posted by ondesx View Post
Happy to know that you agree with Mr. Pass and me."!


Only Nelson, your just riding on his coat tails, he showed us this over a year ago, and designed a buffer for the Lightspeed so it can drive his low impedance amps, don't take his credit, it's not professional at all.



"![/QUOTE]I think you gave a wrong explanation of a subjective fact. Me and other think that the subjective improvement of the series-shunt setup is almost only due to the odd harmonics and, moreover, we know where are coming from, these odd harmonics..."![/QUOTE]


Only you belive this, read what owners of high end active pre's have found, over 300 posts
AudiogoN Forums: Lightspeed Attenuator - Best Preamp Ever?

Cheers George
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Old 4th December 2010, 08:41 AM   #3745
ondesx is offline ondesx  France
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Quote:
Only you belive this, read what owners of high end active pre's have found, over 300 posts
You're kidding, aren't you ? Because ten or even thousand of people prefer a distorted sound is enough to proof that your explanation of "contact issue" is true ?...

Well, I think we must stop this discussion here since religion and science aren't on the same level...

Before stopping this vain hope of mutual understanding, here you'll find a visual evidence that our senses are sometimes fooled... What do you think of the gray level of squares A and B ?...
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Old 4th December 2010, 09:46 AM   #3746
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Default Things have now stopped screeching in the night . . .

Sounds to me Dave like the Sowther is ringing it's brains out with the load (7K-12K) load that the Lightspeed presenting . . .

And, as it's sounding to me now, you were spot on. I dug out an old (Ben Duncan's 1988 HFNRR design) op-amp I/V stage from where it's lain under the bed these last 10 years and swapped it for the Sowthers. It's working a treat.

Many thanks!
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Old 4th December 2010, 09:49 AM   #3747
soongsc is offline soongsc  Taiwan
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Quote:
Originally Posted by ondesx View Post
You're kidding, aren't you ? Because ten or even thousand of people prefer a distorted sound is enough to proof that your explanation of "contact issue" is true ?...

Well, I think we must stop this discussion here since religion and science aren't on the same level...

Before stopping this vain hope of mutual understanding, here you'll find a visual evidence that our senses are sometimes fooled... What do you think of the gray level of squares A and B ?...
Now, I call this trying to involved unrelated data to prove a point. Shame. So if you wish to stop, nobody is going to beg you to to continue.

I have asked you about the specific resistance values of your test setup, you have never provided a valid answer. Seems like you are not quite sure what you did.
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Old 4th December 2010, 10:00 AM   #3748
soongsc is offline soongsc  Taiwan
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Originally Posted by ondesx View Post
This is just... untrue ! And George himself claims just the contrary... even for bad reasons !




You're definitely not in agreement with what most of the professional audio engineers know for a long time ago now... Please, would you explain what means exactly your signature : "Hear the real thing!"
Distortion measurements is only one means of troubleshooting a circuit under the assumption that linear behavior should be a goal. However, even though harmonics exist through this kind of measurement, it may create a perception of tone in an instrument played. This does not mean it will sound bad, it just sounds different. Since, for example, different violins are going to sound different anyway, so it does not matter if the reproduction has a different harmonic content because you don't know what the original one sounds like anyway. Therefore, the reproduction can still sound real. This is why I have the signature to "Hear the reall thing", when you are able to percieve certain characteristics in an instrument that cannot be properly analyzed through data, you know what to listen for. So from what I can see from the data you look at, it's probably going to take about 3 to 4 years to really start to get the understanding involved with linking data and listening perception.

For the record, I currently do not use LDRs, and have only had one listening session with those connected to an amplifier I have as a demo to a third person. The LDRs beat the pants off the volume control I had in there. At that time, I was not aware how the input impedance varied with frequency. Therefore, I would encourage you to do input impedance measurements on your LDRs. Distortion measurements will not tell you what you are looking for.
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Old 4th December 2010, 10:39 AM   #3749
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Originally Posted by sepolansky View Post
ondesx:

Have you listened to a Lightspeed or a clone? What were the test conditions? Sources, power amps, speakers, source material, etc.? What sonically did you observe as the defecit when comparing your LDR attenuator to the product of your "perfect attenuation research"?

When you performed your testing of the LDRs, when you observed variations from test to test, what were your lab conditions? Did you check each LDR at the same temperature each time? George has repeatedly stated the importance of potting the LDRs for thermal tracking between them. Is this what you did? Did you select and match a quad, or a pair, then pot them and re-test at a later time at the same temperature, or did you note the temperature change? Air blowing on the LDRs affects their resistance. Did you encase the LDRs when testing to assure that was not the cause of the variation?

A common claim made in this hobby is the notion of a "distortion" which makes the listening experience more pleasant. That concept used to deride both the individuals using the distorted technology as well as the equipment: i.e., "You guys just like the sound of this distortion without realizing that it's a distortion that you like. We enlightened people don't fall prey to that fallacy." From my own point of view, improved clarity, resolution of low-level detail, a stable "sound field", reproduction of high frequencies without an added "edge" (which is not present in live, unamplified music), bass without boominess, but with excellent definition do not count as distortions.

Whatever your ideal stepped attenuator form is, will you be willing to set up a demonstration, comparing it to the [euphonically distorted?] Lightspeed, or a clone? I'm sure some participants in this thread must be near enough to you to make such a comparison a reality. You could really show us something.

Stuart
So you won't have to look it up, here I am quoting myself.

I think I had it right back then. Starting with post 3677, I think ondesx's points can be summarized thus:

-LDRs have greater distortion than a simple resistor or stepped attenuator
-The lowest measured distortion device is what we must listen to
-"We", known to this forum as "ondesx" have developed a superior product to any LDR based attenuator
-ondesx's attenuator's actual configuration/schematic must be kept secret, although he has no product to sell
-ondesx is better and has a better understanding of the science/electronics/measurements/etc. than the rest of us (side note is that he used another member of "we" to obtain those measurements)
-If you disagree with him, you are following a religion, not a science

I asked specifically if he had ever built or listened to a Lightspeed or clone. What system(s) had he used to listen to his or any other attenuator versus the subject of this thread. I asked what deficits he heard in the LS. I asked about his testing methodology to ensure temperature wasn't causing his perceived variations. Finally, I wondered if he would be willing to demonstrate his product in comparison to an LDR attenuator.

The answers were predictable. No reply to system used, whether he'd ever listened to or built an LDR attenuator. Vague replies about a "standard" test method. No reply as to the sonic flaws heard in the LS. Naturally, he lives in a part of the world far away from any one else who might own an LDR based attenuator.

His insinuations continue about those of us who use human ears to evaluate various products whose purpose is to provide us with the most realistic sounding reproduction of music possible as perceived through our human ears.

I may be wrong, but I think that onedesx has never listened to an LDR setup. I also think that in the near future, the not-for-sale Jackspeed will soon become a commercial product and its supporting literature will tout its superiority over the LS (and probably everything else ever made).

Sorry, but for me, this argument with ondesx is pointless.

Stuart
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Old 4th December 2010, 11:06 AM   #3750
soongsc is offline soongsc  Taiwan
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Heh, lot's of companies are trying to pump things out without really managing comparisons with older products. I bought a new cell phone thinking it had more features than my old one, only to discover the phone is not as smart as my old smart phone. Product support is even more dumb, they did not know more than the phone owner.
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