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Old 21st December 2010, 05:39 AM   #3871
udailey is offline udailey  United States
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1: He was being friendly.
2: He wasnt talking about you.
I have to get to bed. Was going to post 3 and 4 but they werent friendly and I bet you know who they were about.
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Old 21st December 2010, 06:27 AM   #3872
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Onesex, I don't understand, you have monotonously tried to denigrate the Lightspeed Attenuator since a few pages back for it's so called unacceptable distortions, why do you persist in this thread. The only way your going to be happy is by including it into an active stage and then putting a s--- load of feedback around it to satisfy the measurement side of yourself.
Cheers George
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Old 21st December 2010, 08:58 AM   #3873
ondesx is offline ondesx  France
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Quote:
Originally Posted by georgehifi View Post
I don't understand, you have monotonously tried to denigrate the Lightspeed Attenuator since a few pages back for it's so called unacceptable distortions, why do you persist in this thread...
Now you said it : you don't understand... I haven't "denigrate" the LS, I said that the distortion values aren't compatible with the development of a high-end attenuator. This is a totally different sentence. And this is why I choose a different way to achieve this goal...

Anyway, I acquired enough skill in the improvement of this device to help those who want (as previously said in post #3778). Remember the warning of the moderator : "If you're not interested in engaging other members who have technical criticisms, you're under no obligation to do so." Again, I understand you're happy with your simple LS MkII. And those who already are like you, don't have question or intention to change anything. It's OK for me...

But, some other, like I did it in the past, are probably ready to improve this design. Why would you prohibit to all these guys to benefit from some developments of the community ? Isn't a contradiction with the reason of being of this forum ?...
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Old 21st December 2010, 10:28 AM   #3874
soongsc is offline soongsc  Taiwan
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I think what George is saying is that you can also open a new thread to talk about your ideas like George has done. Note that most forum members just say directly what the distortion is caused by. But further discussion on what the improvement is can be discussed in a different thread. If you have normal measurements to show how much better it is, then fine, post the product measurements. Up to now, nobody has even heard the product you are talking about.

Many Chinese based forums communicate as you do, but when invited to any audiophile gathering to demonstrate, they become very defensive when they cannot demonstrate audibly agreeable improvement.

I'm sure there are probably a few people that participate in this forum whom live not too far from where you are. Maybe another's listening impression might help.
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Last edited by soongsc; 21st December 2010 at 10:43 AM.
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Old 21st December 2010, 12:50 PM   #3875
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All this worrying about attempting (close to) perfect channel balance is a waste of time. Too many variables exist for the "perfection" to matter.

Your ears are not perfectly matched
Your room most probably has different sonic absorption/reflection properties from side to side (depending on who else is in the room, at least)
Your phono cartridge (if you use records) doesn't have perfect channel match
Your tube equipment almost certainly has different gain from channel to channel.
Your speakers will have some channel to channel differences.
You won't always be seated to within 0.1% of the center of the speakers
Your source material won't be that closely balanced

Simplicity is the ultimate sophistication. There are three reasonable alternatives:

Live with minor imbalances (George's setup)

Add a balance control (as Uriah does)

Build with two gain controls. Set one for volume then set the other to balance, it's really quite easy.

Want to improve it? Make a better LDR!

Stuart
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Old 21st December 2010, 02:25 PM   #3876
soongsc is offline soongsc  Taiwan
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It's more expensive to try and make a better LDR.
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Old 21st December 2010, 02:26 PM   #3877
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It sounds to me like Ondesx is proposing a system of control that reduces distortions by perfectly matching current to that required to produce a given resistance using microprocessor controlled current sources to feed each LDR with the currents chosen from a look up table to determine the current needed for each level of attenuation. That sounds like it would be more accurate and the concept is fairly simple to those with programming capabilities. Not me, but my son thinks he could do it rather quickly.

The net sonic result is probably significantly up the diminishing returns curve, compared to the Lightspeed. You'd also have to concern yourself with shielding the digital portion from the analog. I don't know if that would be a significant issue or not.

George has been kind enough to share his work with us and many people seem to like the performance a lot, even though there may be areas of that may be improved. Yes, it likes a high impedance load. George stated that. It's fairly easy to add a buffer if needed. Better tracking may produce better distortion measurements, but is it audible? If it is to you, enjoy. Don't denigrate a design that many find quite satisfactory because it doesn't meet YOUR needs.

Ondesx, you seem to have a viable idea. However, the level of criticism of the Lightspeed and personal attacks against George are completely unwarranted. Many of us like to go for the simplest solution that works well. This thread is about an idea that performs very well with a simple implementation. If you want to discuss a way to potentially take the performance up a notch, why not start your own thread titled something like "A More Accurate Lightspeed" the way Zen Mod did with his "poor Serbian man's Lightspeed" thread?

Your continued participation in this thread is fairly disruptive and the tone of many of your posts makes it difficult to focus on the merits of your concept or George's. I (and probably others) would be interested to see your ideas in another less confrontational environment. Maybe you don't mean it that way, but much of what you write come off as harsh. I hope that you will start a new thread to discuss your ideas.
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Old 21st December 2010, 02:31 PM   #3878
soongsc is offline soongsc  Taiwan
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Quote:
Originally Posted by ondesx View Post
Either I haven't explained it correctly or you don't understand English, ...
I learned English before I learned any other language, so what can I say?
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Old 21st December 2010, 03:23 PM   #3879
ondesx is offline ondesx  France
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Quote:
Originally Posted by BobEllis View Post
It sounds to me like Ondesx is proposing a system of control that reduces distortions by perfectly matching current to that required to produce a given resistance using microprocessor controlled current sources to feed each LDR with the currents chosen from a look up table to determine the current needed for each level of attenuation. That sounds like it would be more accurate and the concept is fairly simple to those with programming capabilities. Not me, but my son thinks he could do it rather quickly.
OK Bob. It is exactly what I done, but the distortion won't lower by a correct matching... Unfortunately !

It seems that you or somebody near you, can do it. Nice. It's enough for me...

Happy Christmas !

Last edited by ondesx; 21st December 2010 at 03:26 PM.
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Old 21st December 2010, 04:25 PM   #3880
AndrewT is offline AndrewT  Scotland
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Neither Ondesx nor anyone else can call it "lightspeed".
George owns lightspeed and on this Forum only his product/thread can use that title.
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