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Simplistic NJFET RIAA
Simplistic NJFET RIAA
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Old 21st March 2010, 11:00 PM   #3411
merlin el mago is offline merlin el mago
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Ok exact values as Salas designed for resistors plus 2.2Meg over 47K in parallel, for caps start with 45nF & 15nF & fine tune adding small caps.
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Old 21st March 2010, 11:59 PM   #3412
RCruz is offline RCruz  Switzerland
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Simplistic NJFET RIAA
Very good but I would stick to 2M or 1M8 (even closer if you get the exact 6k8)
IMO a difference of 20ohm in the 6k8 can easily be heard.

For cap tuning always take in consideration that C2/C3 should be 2.916.

Thank you again for your input.... It prooves my calculator works correctly.
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Old 22nd March 2010, 12:44 PM   #3413
merlin el mago is offline merlin el mago
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Quote:
Originally Posted by RCruz View Post
For cap tuning always take in consideration that C2/C3 should be 2.916.
How can calculate?
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Old 22nd March 2010, 01:34 PM   #3414
RCruz is offline RCruz  Switzerland
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Simplistic NJFET RIAA
Quote:
Originally Posted by merlin el mago View Post
How can calculate?
Always make sure C2/C3 = 2.916

IMO this relation is critical for linearity.
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Old 22nd March 2010, 02:28 PM   #3415
merlin el mago is offline merlin el mago
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SALAS RIAA MATCHING BY KABUSA

LEFT & RIGHT
R = 3.300+47.000 // 1.000.000 = 47.891 input Kabusa R1
Kabusa R1 47.891 - R4 6.963 - C2 45nF644 - C3 15nF661

45nF644/15nF661 = 2.92 very, very close/near your calculation

An useful calculator for capacitors in series & parallel:

http://www.electronics2000.co.uk/cal...calculator.php

Last edited by merlin el mago; 22nd March 2010 at 02:35 PM.
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Old 22nd March 2010, 02:35 PM   #3416
AndrewT is offline AndrewT  Scotland
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full stops mean what?
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regards Andrew T.
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Old 22nd March 2010, 03:01 PM   #3417
merlin el mago is offline merlin el mago
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Quote:
Originally Posted by RCruz View Post
Very good but I would stick to 2M or 1M8 (even closer if you get the exact 6k8)
Kabusa Riaa calculator
R= 3.300+45.804 (47k//1Meg8) // 1.000.000 = 46.805 input Kabusa R1
Kabusa R1 46.805 - R4 6.805 - C2 46nF723 - C3 16nF024

C2/C3 = 2.92

Your suggestion is very good because maintain the R4 value 6K8 & the linearity also is very good.

So I need to match the following values that I don't have:

LEFT
R3 add 1Meg8
R5 change 1Meg13 for 1Meg
C2 start with 46nF3 & reach adding more caps till 46nF723 max.
C3 start with 15nF6 & reach adding more caps till 16nF024 max.

RIGHT
R3 change 46K8 to 47K& add 1Meg8
R4 change 6K79 to 6K8
R5 change 998K to 1Meg
C2 start with 46nF4 & reach adding more caps till 46nF723 max.
C3 start with 15nF6 & reach adding more caps till 16nF024 max.

That's right?
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Old 22nd March 2010, 03:03 PM   #3418
RCruz is offline RCruz  Switzerland
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Simplistic NJFET RIAA
You got it !

Just a hint.... IMO to reach C2 better value you should use three caps: 46,4n + 300p + smaller cap

It seems to work better this way and it easier to tune.

Last edited by RCruz; 22nd March 2010 at 03:08 PM.
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Old 22nd March 2010, 03:09 PM   #3419
merlin el mago is offline merlin el mago
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Can't possible without your (Ricardo, Salas, nicoch46 & many others) help.
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Old 22nd March 2010, 03:16 PM   #3420
RCruz is offline RCruz  Switzerland
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You will get used to it.... It seems to be a diyaudio prerogative.

It feels good to help good people

Of course, by helping the good ones we tend to learn faster.
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