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Old 3rd May 2012, 10:22 AM   #5041
DF96 is offline DF96  England
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Quote:
Originally Posted by dvv
When in trouble with argumentation, they tend to use the Ultimate Weapon - but I have a PhD!
Actually, in my experience the converse is more often true. When reasoned argument is failing, the other person (losing the factual argument) says something like "what do you know about practical things - I bet you have a PhD". Thank you for demonstrating this technique for us. There was even one guy on here who tried to solve disputes (and gain sympathy?) by repeatedly declaring that he is a TV repair man!
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Old 3rd May 2012, 10:23 AM   #5042
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Default Sorry

I had to recommend a monitoring system recently for a recording studio . I recommended Marantz Model 9 and Quad ESL 63 . It was a technical solution to the request made .

Did I get it right ?

Last edited by nigel pearson; 3rd May 2012 at 10:25 AM.
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Old 3rd May 2012, 10:44 AM   #5043
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Neah, it is just "cool".
People sometimes will act different just to differentiate from the "crowd" that they live in. Some crave to show-off opposition to mainstream trends as their indentity, to state "I am special" (therefore better noticed from the rest of the group).
Any tool is good for that: tatoos, piercings, overpriced Apple products, LP collections, tubes amplifiers, NOS made with DAC's that are not in production anymore...
Quote:
Originally Posted by DF96 View Post
Thank you for demonstrating this technique for us. There was even one guy on here who tried to solve disputes (and gain sympathy?) by repeatedly declaring that he is a TV repair man!
Ah, some here are goood at that kind of arguments. Will twist everything to their use... For example engineers for them are sometimes geinuses (when desing a DAC that is not in production anymore) or just deaf idiots (when specify the use of OS filters or OpAmps in final stage).

Last edited by SoNic_real_one; 3rd May 2012 at 10:51 AM.
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Old 3rd May 2012, 10:47 AM   #5044
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Default Nulling

Any ideas

Abstract

A dominant distortion mechanism in audio power amplifiers results from nonlinearity in the voltage and current transfer functions within the power output stage. A technique is presented that uses a magnetic differential sensor to sense this distortion and to apply a supplementary error-correcting feedback path within the amplifier, in addition to overall negative feedback. Differential-current derived feedback is explored and the technique is shown to be applicable to both voltage and current transfer errors. Analysis reveals the system alignment for obtaining a distortion null and these results are confirmed using nonlinear transient analysis. Basic system topologies are presented using voltage transfer and transconductance gain cells as an aid to complete amplifier synthesis. Comparisons are made with feedforward-feedback error correction where the current-dumping amplifier is reconfigured using differential-current feedback. Generalisations are made to a multi-loop nest of amplifiers using individually aligned error correcting paths to achieve corresponding improvements in distortion reduction
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Old 3rd May 2012, 11:01 AM   #5045
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Wow, Nigel, where is THAT paper?

Last edited by john curl; 3rd May 2012 at 11:16 AM.
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Old 3rd May 2012, 11:09 AM   #5046
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Quote:
Originally Posted by dvv View Post
Actually, as you said yourself, I never manage to get it all just right as per Otala. Part of the reason for that is my extremely limited parts selection. For example, Thorsten told me even he has problems finding the Hitachi lateral FETs he used for drivers, and that's saying something, Germany's market is extremely well supplied in general.
dvv, thanks for your active position in this discussion, but, at analogy with one saying, "chair" designers will never find common position with "practice" designers. I belong to the last group, since for me it became obvious quite a long time ago - models are still very far from reality in the field of audio. Designing audio is much more tricky and less grounded by "theory" than designing instrumentation and control equipment.
Open Loop Bandwidth and quality of parts used (especially capacitors) are of the major importance. Hope the efforts of John Curl will bring something new upon the table.
If finding of proper parts really matters to you, I could try to send you some laterals, we have them supplied mainly from Singapore (almost sure not fake).
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Old 3rd May 2012, 11:14 AM   #5047
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We get our 1/2A complementary 'Hitachi' type mosfets from Great Britain. I can't measure any difference.
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Old 3rd May 2012, 11:31 AM   #5048
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Default FET

John is that Exicon ? I find they behave very well ?
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Old 3rd May 2012, 11:33 AM   #5049
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At present, I find it grounded by practice to use only RF transistors at the output stage.
Such an approach sounds as a nonsense for those who designs for manufacturing companies, but among DIYers we concluded, that NFB designs definitely benefit from RF transistors at output stage, their sound comes close to that from NoNFB designs, with additional pluses remaining at the bottom end.
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Old 3rd May 2012, 12:10 PM   #5050
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Default Dr Who ?

It's that man again Dr M H .

Looks interesting .

http://www.essex.ac.uk/csee/research...DCDF%20IEE.pdf
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