Hi,
has anybody an article, link or software where the calculating of parts values for the riaa filter is explained deeply for various concepts? That explanation should include the relevant surroundings like impedance of following stages etc.
I would really like to understand such things correctly, in existing designs as well as for trying own ideas.
greets & thanks,
Rudiger
has anybody an article, link or software where the calculating of parts values for the riaa filter is explained deeply for various concepts? That explanation should include the relevant surroundings like impedance of following stages etc.
I would really like to understand such things correctly, in existing designs as well as for trying own ideas.
greets & thanks,
Rudiger
I have two Excel files, one for inverting RIAA amp and one for a non-inverting.
Anybody who wants these send me an email,
Do not post me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, etc here
Output is like this:
http://home5.swipnet.se/~w-50674/hifi_pics/hifi_100pr/riaa_diagram_ai.gif
http://home5.swipnet.se/~w-50674/hifi_pics/hifi_100pr/riaa_tolerance_ai.gif
Anybody who wants these send me an email,
Do not post me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, me too, etc here
Output is like this:
http://home5.swipnet.se/~w-50674/hifi_pics/hifi_100pr/riaa_diagram_ai.gif
http://home5.swipnet.se/~w-50674/hifi_pics/hifi_100pr/riaa_tolerance_ai.gif
Stanley P. Lipshitz.
On RIAA Equalization Networks.
Journal of the Audio Engineering Society, 27(6), June 1979.
Peter J. Baxandall
Comments on "On RIAA Equalization Networks"
Journal of the Audio Engineering Society, 29(1), Jan 1981.
Stanley P. Lipshitz
Author's Reply to "Comments on 'On RIAA Equalization Networks'"
Journal of the Audio Engineering Society, 29(1), Jan 1981.
On RIAA Equalization Networks.
Journal of the Audio Engineering Society, 27(6), June 1979.
Peter J. Baxandall
Comments on "On RIAA Equalization Networks"
Journal of the Audio Engineering Society, 29(1), Jan 1981.
Stanley P. Lipshitz
Author's Reply to "Comments on 'On RIAA Equalization Networks'"
Journal of the Audio Engineering Society, 29(1), Jan 1981.
Not that I know of. If you do not want to order it from the AES, you will have to find a library that holds back issues of the AES journal.
ray
ray
It's not very expensive to order from AES, a couple of dollars. I have ordered a couple of old articles and it has been a painless process and the pdf files have been nice scanned.
The Lipshitz article deals with pole-zero interaction due to the effects of finite open-loop gain in a feedback arrangement.
If you want it to be accurate, passive EQ is the best choice. I have been able to construct EQs that were accurate to +/- 0.02 dB that way.
In any case, there is a hump between 200 and 500 Hz that is hard to remove. Doing so yields an accurate sound that few seem to like.
If you do go passive, somewhere I have a program that plots the output error. If you supply me with the values that you have, I could calculate it for you.
Jocko
If you want it to be accurate, passive EQ is the best choice. I have been able to construct EQs that were accurate to +/- 0.02 dB that way.
In any case, there is a hump between 200 and 500 Hz that is hard to remove. Doing so yields an accurate sound that few seem to like.
If you do go passive, somewhere I have a program that plots the output error. If you supply me with the values that you have, I could calculate it for you.
Jocko
My non-inverting Excel file takes this into account but it's tricky to really compensate for it.
As Jockpo says, it's easier to have separate filters for each time constant.
An example of this can be found in an application note somewhere at Analog Devices.
As Jockpo says, it's easier to have separate filters for each time constant.
An example of this can be found in an application note somewhere at Analog Devices.
RIAA
If you go to the Beige Bag software site you will find several pages of info given by John Broskie about building active and passive RIAA circuits and how to simulate them. You could even download a trial version of Beige Bag's Spice software for free and try out the circuits and any modifications that you may want to try out. The circuit files shown can be opened with their software. It's great , easy to use. Try it out.
Cheers.
http://www.beigebag.com/resources.htm
If you go to the Beige Bag software site you will find several pages of info given by John Broskie about building active and passive RIAA circuits and how to simulate them. You could even download a trial version of Beige Bag's Spice software for free and try out the circuits and any modifications that you may want to try out. The circuit files shown can be opened with their software. It's great , easy to use. Try it out.
Cheers.
http://www.beigebag.com/resources.htm
thanks for all the replies!
e.g. I try to understand the network of la boheme:
http://www.klaus-boening.de/html/schematics.html#MKIIInew
As a reference, one might use
http://www.kabusa.com/riaa.htm
So, R1 is the output impedance of the preceding stage, which with RL=4.7K should be around 4.5K.
According to the reference, R1 should be around 7.3K with the chosen values. Seems I don't know what happens in a balanced design...
Rüdiger
e.g. I try to understand the network of la boheme:
http://www.klaus-boening.de/html/schematics.html#MKIIInew
As a reference, one might use
http://www.kabusa.com/riaa.htm
So, R1 is the output impedance of the preceding stage, which with RL=4.7K should be around 4.5K.
According to the reference, R1 should be around 7.3K with the chosen values. Seems I don't know what happens in a balanced design...
Rüdiger
Lipshitz article
AES preprint # 1424, Nov. '78.
Deals with active de-emphasis circuits, inverting and non-inverting;
Active inverting pre-emphasis;
Passive pre-emphasis.
Jocko
AES preprint # 1424, Nov. '78.
Deals with active de-emphasis circuits, inverting and non-inverting;
Active inverting pre-emphasis;
Passive pre-emphasis.
Jocko
IIRC, Lipshitz (or someone following him) wrote up passive and active RIAA calculations in Audio Amateur. This would have been in the late '70s or early '80s. He took into account the "secret" pole and the interaction between the RCs that determined the time constants.
As a side note, anyone building their own RIAA stage ought to spend an afternoon and $50 or so to build a buffered precision inverse RIAA network. At some point, you have to turn the calculations into real ciscuits, and trimming is a good thing to be able to do.
As a side note, anyone building their own RIAA stage ought to spend an afternoon and $50 or so to build a buffered precision inverse RIAA network. At some point, you have to turn the calculations into real ciscuits, and trimming is a good thing to be able to do.
Yeah, but...............
That assumes that their inverse network is correct.
The high-tech method that I am able to employ involves generating the exact RIAA curve in software on my FFT, and comparing it to the UUT.
Jocko
That assumes that their inverse network is correct.
The high-tech method that I am able to employ involves generating the exact RIAA curve in software on my FFT, and comparing it to the UUT.
Jocko
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.
Not every hobbyist has your software 😉 That's a slick way to go, but not one I can implement without sending you my preamp to tweak.
Not every hobbyist has your software 😉 That's a slick way to go, but not one I can implement without sending you my preamp to tweak.
Riaa
Walt Jung's Op-amp Applications book shows a method for doing reponse deviations in SPICE, by comparing sim results to an ideal Laplace transform.
Probably similar to what Jocko is doing with real circuits.
I'll dig out the ref later.
Andy.
Walt Jung's Op-amp Applications book shows a method for doing reponse deviations in SPICE, by comparing sim results to an ideal Laplace transform.
Probably similar to what Jocko is doing with real circuits.
I'll dig out the ref later.
Andy.
You DON"T want to send me your preamp???
Why not? I'm only in in for the money.
(Gratutious image of Mothers of Invention album left off.....for now at least.)
Anyway, noise and sonics are not the problem. Pole-zero interaction is there even in passive networks, and it if you saw how much a small change makes, you would understand why ALW and I have the upper hand.
The other problem is getting a source that has good frequency stability and resolution. And way of really measuring it. I imagine a good sound card and FFT program would be a step in the right direction.
Hey.......I know......I could make a pre-emp box......and sell it for $$$.
Only no one tell PerAnders, he may try to beat me to it.
Jocko
Why not? I'm only in in for the money.
(Gratutious image of Mothers of Invention album left off.....for now at least.)
Anyway, noise and sonics are not the problem. Pole-zero interaction is there even in passive networks, and it if you saw how much a small change makes, you would understand why ALW and I have the upper hand.
The other problem is getting a source that has good frequency stability and resolution. And way of really measuring it. I imagine a good sound card and FFT program would be a step in the right direction.
Hey.......I know......I could make a pre-emp box......and sell it for $$$.
Only no one tell PerAnders, he may try to beat me to it.
Jocko
Reference
Walt Jung "SPICE Technique Compares Frequency Responses", EDN, November 25, 1993, pp.188 and 190.
Section 6.20 of the latest Op-Amp Applications book has the Laplace transform listing.
Andy.
Walt Jung "SPICE Technique Compares Frequency Responses", EDN, November 25, 1993, pp.188 and 190.
Section 6.20 of the latest Op-Amp Applications book has the Laplace transform listing.
Andy.
Jocko, that's the real problem with passives- normally, just changing a tube will throw off the EQ unless the network is buffered, which isn't great design. So will tube aging. Feedback EQ has passive beat all to hell for stability, which, of course, is why I use passive. 😉
What's wrong with a buffer????
Some of us use JFETs. Nice and quiet, no aging problem. Passive is easier to tune, and does not have to worry about open loop gain to interact with, or worse, degrade and really interact with.
And then you get into the whole amount of feedback vs. frequncy thing with active EQ.
No, thanks. I'll stick to passive.
Jocko
Some of us use JFETs. Nice and quiet, no aging problem. Passive is easier to tune, and does not have to worry about open loop gain to interact with, or worse, degrade and really interact with.
And then you get into the whole amount of feedback vs. frequncy thing with active EQ.
No, thanks. I'll stick to passive.
Jocko
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