i try to understand the riaa network of
http://www.klaus-boening.de/html/sc...s.html#MKIIInew
With the given values and the aid of
http://www.kabusa.com/riaa.htm ,
R1 should be around 7,2 K. In Klaus' riaa there is no Resistor for R1; it seems that it's made of the output impedance of the previous stage. That impedance, with the Drain-Resistor of 4.7K, should be around 4.5K in a single-ended design.
So, how do we reach the desired 7.2K?
Rüdiger
http://www.klaus-boening.de/html/sc...s.html#MKIIInew
With the given values and the aid of
http://www.kabusa.com/riaa.htm ,
R1 should be around 7,2 K. In Klaus' riaa there is no Resistor for R1; it seems that it's made of the output impedance of the previous stage. That impedance, with the Drain-Resistor of 4.7K, should be around 4.5K in a single-ended design.
So, how do we reach the desired 7.2K?
Rüdiger
RIAA
Go to the Hagerman Technology pages. www.hagtech.com.
Check out the following pages. (some of the links are hard to find)
"Bugle" Phono Preamp kit
"On Reference RIAA Networks"
"Cartridge Loading"
Go to the Hagerman Technology pages. www.hagtech.com.
Check out the following pages. (some of the links are hard to find)
"Bugle" Phono Preamp kit
"On Reference RIAA Networks"
"Cartridge Loading"
SY, you are right completely. But not only for RIAA accuracy, but for testing on stress signals (square waves) and for sonic evaluation also. For example “An Active Inverse RIAA Circuit”, TAA, 1991, January
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Getting an inverse correct is a lot easier- you don't care much about noise or sonics, just freq response. There are some excellent published designs (I used one from AA), and building one up with 0.5% or better tolerance components (I used 0.1% for mine) and input and output buffers will get you something pretty nice without having to trim.
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Getting an inverse correct is a lot easier- you don't care much about noise or sonics, just freq response. There are some excellent published designs (I used one from AA), and building one up with 0.5% or better tolerance components (I used 0.1% for mine) and input and output buffers will get you something pretty nice without having to trim.
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passive RIAA calculation
Hi, try this:
http://people.zeelandnet.nl/eschoester/jaccos_place/passieve_RIAA/passieve_RIAA.html
It is considered to be as exact as possible within the constrains of the schematic, ie. no capacitive loading of the circuitry by means of a Miller-capacitance of the following amplifier.
With regards,
Hi, try this:
http://people.zeelandnet.nl/eschoester/jaccos_place/passieve_RIAA/passieve_RIAA.html
It is considered to be as exact as possible within the constrains of the schematic, ie. no capacitive loading of the circuitry by means of a Miller-capacitance of the following amplifier.
With regards,
Bugle phono RIAA done correctly?
I got the Haggerman Bugle phono board to play records again. The board looks very nice. The spec sheet says RIAA +/- 0.5 db from 30 Hz to 60 KHz. However when I simulate with the given values, it appears that the two shelf filters are set for the RIAA filter points, but the resulting frequency response does not meet the specifications of the RIAA table (using the Analog Devices data table) because of the second filter causing "extra" losses.
What's right - text book design or the standard? Is the playback standard correcting the recording interaction? Or did I do something wrong in my simulation?
The board uses 3 opamps with the above mentioned two section passive equalization, making changes easy.
If the standard is right my initial correction is to:
1. decrease the loss in the first shelf filter by increasing the "load" side resistor.
2. Decrease the first shelf filter capacitance to make up for the change in both frequency points caused by change #1.
3. Decrease the second capcitor value to push the second shelf filter effects out a little farther.
After this, discrete JFET RIAA, maybe the phono pearl. The Bugle is cheap and easy, and should have good entry level performance.
I got the Haggerman Bugle phono board to play records again. The board looks very nice. The spec sheet says RIAA +/- 0.5 db from 30 Hz to 60 KHz. However when I simulate with the given values, it appears that the two shelf filters are set for the RIAA filter points, but the resulting frequency response does not meet the specifications of the RIAA table (using the Analog Devices data table) because of the second filter causing "extra" losses.
What's right - text book design or the standard? Is the playback standard correcting the recording interaction? Or did I do something wrong in my simulation?
The board uses 3 opamps with the above mentioned two section passive equalization, making changes easy.
If the standard is right my initial correction is to:
1. decrease the loss in the first shelf filter by increasing the "load" side resistor.
2. Decrease the first shelf filter capacitance to make up for the change in both frequency points caused by change #1.
3. Decrease the second capcitor value to push the second shelf filter effects out a little farther.
After this, discrete JFET RIAA, maybe the phono pearl. The Bugle is cheap and easy, and should have good entry level performance.
There was a thread very recently on inverse RIAA:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=73211
http://www.diyaudio.com/forums/showthread.php?s=&threadid=73211
Onvinyl said:
Borberly descirbes the passive RIAA in Audio Amateur 4/84 and 1/85. He references articles by Jung and Marsh in those articles. Erno has many of his articles archived on his site (but I don't know if those from the 1980's are there.) www.borberlyaudio.com
Tritschler had an article on passive RIAA in AX -- October 2003 -- the acuracy is very, very good -- a pair of boards is $49 but their (Tritschler) website went off the air a few weeks ago.
In Tritschler's article he used 417a's or their equivalent (5842?)-- but their boards used 6DJ8's.
Hi,
If you want to simulate your circuit in PSpice you can use a Laplace source for the inverted RIAA function:
(1+tau_1*S)*(1+tau_3*S)/(1+tau_2*S)
And if you want to incorporate the 3.18 us time constant:
(1+tau_1*S)*(1+tau_3*S)/((1+tau_2*S)*(1+tau_4*S))
Both describe exactly the inverse RIAA and have a gain of 0 dB at 0 Hz.
tau_1 = 3180u
tau_2 = 318u
tau_3 = 75u
tau_4 = 3.18u
Cheers
If you want to simulate your circuit in PSpice you can use a Laplace source for the inverted RIAA function:
(1+tau_1*S)*(1+tau_3*S)/(1+tau_2*S)
And if you want to incorporate the 3.18 us time constant:
(1+tau_1*S)*(1+tau_3*S)/((1+tau_2*S)*(1+tau_4*S))
Both describe exactly the inverse RIAA and have a gain of 0 dB at 0 Hz.
tau_1 = 3180u
tau_2 = 318u
tau_3 = 75u
tau_4 = 3.18u
Cheers
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