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Old 15th January 2013, 08:05 AM   #11
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Hi!

Quote:
Originally Posted by ClausD View Post
I like your comment on my question, and that is one of the mythos. What you posted is all correct and everybody knows it and it is published and copied several thousand times in the internet.
But what about if you want design your own LCR network, e.g. with an impedance of 2.2kOhm. Do you know how to calculate all the components? What is about the answer to add the 3.18us high frequency cut-off time constant. Do you have a reference for the design?
Again, I don't see any mythology about LCR. It is one possible way to do filter design.

Changing the impedance is easy. It is more difficult to calculate a new filter for different corner frequencies or to add other constants. A lot of the theory is covered for example in the book 'Motion Picture Sound Engineering'.

I have used various LCR type filters over the years and calculated many duifferent ones for example also for crossover use. These are simple to calculate. I have written about that here:

VinylSavor: Making of a Line Level Crossover

Please do share your knowledge. I am curious what you have to say and can possibly learn something new!

Best regards

Thomas
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Old 15th January 2013, 10:19 AM   #12
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Hey Claus,
As Thomas points out, classical constant impedance filters are to be used. These are also covered in "the Audio Cyclopedia". What you call "Tango solution" is not ;-). Pultec was the first company to adapt this technique to RIAA and Tango copied it. I guess Pultec did this in the 40s or 50s using a heavily feedbacked 12AX7(gain)/12AU7(CF)-circuit. http://forums.melaudia.net/attachment.php?aid=594

This is a great thread: http://forums.melaudia.net/showthread.php?tid=230

The 3.18uS you mention is easily adopted(for those who want to) to this network with a single resistor as I showed out in Daves forum. Although it will be an approximation as Neumann used a second order filter at 50kHz.

But please share your findings, this is a great subject.

Last edited by revintage; 15th January 2013 at 10:26 AM.
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Old 6th May 2013, 10:31 PM   #13
ClausD is offline ClausD  United States
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Default White Paper for passive LCR RIAA design including tool

Thanks guys waiting so long for my response.
Attached you find my white paper article, a design tool and some simulation as examples.
Please feel free to response, to copy and let have a nice discussion.
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Old 6th May 2013, 11:32 PM   #14
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Attachment please...
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Old 7th May 2013, 12:40 AM   #15
ClausD is offline ClausD  United States
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Sorry, it was not accepted because of the large file size. For interim solution please use the forum "intactaudio.com" with the title "4th time constant for LCR RIAA". Hopefully, we get a better solution in future. If it's not working please reply. Claus
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Old 7th May 2013, 01:23 AM   #16
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Perhaps this could be posted as an article somewhere on the forum. How large is the attachment you attempted to upload and the format? Send me a PM or report this post and we'll see what can be done.
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Old 7th May 2013, 02:00 AM   #17
Pano is online now Pano  United States
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Quote:
Originally Posted by ClausD View Post
Sorry, it was not accepted because of the large file size.
Yes. the PDF of your paper is 3 megs, too big to attach here. Probably the graphs and the schematics near the end that cause the big file size.
I could try to squeeze it down on Acrobat, but I don't know if it will squeeze enough to post here.
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Old 7th May 2013, 02:04 AM   #18
ClausD is offline ClausD  United States
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Default White Paper for passive LCR RIAA design including too

This is not only an article, it's an PDF file (the article), an Excel file (a tool) and some simulation files all compressed in a zip file. Altogether the file size is approximately 3.2MB. Would be fine if you could help me. Thanks!
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Old 7th May 2013, 02:06 AM   #19
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Yes, I saw the Excel file, it's small and could be posted separately. I'll try reducing the PDF file size tomorrow in Acrobat, if someone else hasn't fixed the problem before then.
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Old 7th May 2013, 02:23 AM   #20
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Here's the link to download the zip folder that contains the PDF and various files.

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