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Old 9th April 2003, 09:11 AM   #1
stigla is offline stigla  Norway
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Default Excact RIAA numbers?

Hi!


I was hoping someone could shead som light over the RIAA response curve.

The points are as usual the 50Hz, 500Hz, 2120Hz and maybe the 50kHz.

My question is:

My guessings are:

20Hz = +20dB
50Hz = +17dB (20-3dB)
500Hz = +3dB
1kHz = 0dB
2120 = -3dB
20kHz = -20dB
50kHz = -25dB (??)

but Im not sure. At least not about that 50kHz...

I recently found this Excel RIAA table, showing numbers that obiously where calculated from one heck of a formula, and the numbers from that table compared to my points up there where not identical.

So, what are the REAL numbers to use? Are this Excel Table accurate? I think so, but I would appreciate some comments, especially on that 50kHz point.

http://www.bonavolta.ch/hobby/en/audio/riaa.htm


Cheers;
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Old 9th April 2003, 10:09 AM   #2
Electrons are yellow and more is better!
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I have an Excel file for three different kinds of RIAA filters.

Send me a message if you want it.

The time constants are:

7950 µs, 20 Hz (not common)

3180 µs, 50 Hz

318 µs, 500 Hz

75 µs, 2122 Hz
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Old 9th April 2003, 10:44 AM   #3
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Quote:
Originally posted by peranders
The time constants are:

7950 µs, 20 Hz (not common)

3180 µs, 50 Hz

318 µs, 500 Hz

75 µs, 2122 Hz
Allen Wright (amongst others) also incorporates a 3.18us constant to compensate for the response of most cutter heads.
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Old 9th April 2003, 10:53 AM   #4
Electrons are yellow and more is better!
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The last time constant is not official but some poeple think it's important. I think it's not very important but if you use a non-inverting amp you can get this almost for free.
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Old 10th April 2003, 12:07 AM   #5
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Default OF IMPORTANCE.

Hi,

Quote:
The last time constant is not official but some poeple think it's important.
Well, I happen to care a lot about that particular part.

Quote:
important but if you use a non-inverting amp you can get this almost for free.
Uh? How does that one go?
What's signal polarity got to do with this?

Can you 'splain that, please?

Cheers,
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Old 10th April 2003, 12:24 AM   #6
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Default After the rock throwing contest ends......

Somewhere I have the RIAA document, from the Beast itself, with the exact numbers. Maybe I'll look for it.

Meanwhile.......this might be fun. [joke]

Looks like Frank is becoming a Texan. Amazing the influence I have on people who actually pay attention.

Jocko
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Old 10th April 2003, 12:27 AM   #7
mlloyd1 is offline mlloyd1  United States
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Default Re: After the rock throwing contest ends......

It's quite scary actually ...

mlloyd1

Quote:
Originally posted by Jocko Homo
... Amazing the influence I have on people who actually pay attention.
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Old 10th April 2003, 12:38 AM   #8
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Default Texas Here I Come.

Hi,

Mon petit pois chiche?

Quote:
Amazing the influence I have on people who actually pay attention.
Just hope it's a two way street so one day I can show you what tubes and vynil can do to cure you of digititis?

How on earth did you guys catch this booby trap anyway?

So the travelling plan is California, Texas, must check some New York ears too ( for onions) and than...Canada???

Cheers guys,
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Old 10th April 2003, 02:06 AM   #9
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Default Here's the equation......

I'm sure that Phred will be more than happy to 'splain it you if need be. [joke]

Jocko
Attached Files
File Type: zip riaaeqn.zip (56.1 KB, 71 views)
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Old 10th April 2003, 07:19 AM   #10
Electrons are yellow and more is better!
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I have three different kinds of RIAA networks. This file did I make for my QSXM3 phono amp. The file is for my personal use, therefore not so pedagogical maybe.
Attached Files
File Type: zip riaa_curve_optimal_noninv.x.zip (22.2 KB, 54 views)
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