Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

RIAA Response question
RIAA Response question
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 28th July 2015, 11:08 PM   #11
ALPUY is offline ALPUY  Uruguay
diyAudio Member
 
Join Date: Mar 2012
Location: Montevideo, Uruguay
Hello. I used the simulator to suggest me Calvin.
I have entered the values of resistors and capacitors I calculated KAB and I have achieved almost 100% of that value using series and parallel.
They think of the RIAA response has been achieved?
RIAA Response question


Then I will look for the difference with the actual curve.
I still do the RIAA investor who suggested me Rayma and see results.
Regards.

Last edited by ALPUY; 28th July 2015 at 11:11 PM.
  Reply With Quote
Old 1st August 2015, 10:39 AM   #12
pos is offline pos  Europe
diyAudio Member
 
pos's Avatar
 
Join Date: Feb 2008
Location: Paris
I am currently implementing a RIAA deemphasis EQ preset in rePhase, but the data I have is not reliable enough.
Could you please export this curve as a 3-column file (frequency, magnitude, phase) with a high frequency range (say 1Hz-100kHz) and high resolution?
  Reply With Quote
Old 1st August 2015, 11:46 AM   #13
AndrewT is offline AndrewT  Scotland
R.I.P.
 
Join Date: Jul 2004
Location: Scottish Borders
Build a reverse RIAA
Series connect the Source - Reverse RIAA - RIAA - measurement system
and then you can measure the frequency response errors.
The error is any anomaly that is not "flat" frequency response.
__________________
regards Andrew T.
  Reply With Quote
Old 1st August 2015, 07:35 PM   #14
paba is offline paba  Canada
diyAudio Member
 
Join Date: Sep 2004
Location: Montreal
But Andrew then you have small errors in inverse circuit and in DUT accumulated no?
  Reply With Quote
Old 1st August 2015, 08:47 PM   #15
Conrad Hoffman is offline Conrad Hoffman  United States
diyAudio Member
 
Join Date: Mar 2007
Location: Canandaigua, NY USA
IMO, with inexpensive equipment you can build a more accurate inverse RIAA circit than you can directly measure RIAA response. Because of the large dynamic range and frequency span, the direct measurement is harder to do accurately than most realize. With the inverse filter you can also look at square wave response, which makes errors stand out like a sore thumb.
__________________
I may be barking up the wrong tree, but at least I'm barking!
  Reply With Quote
Old 1st August 2015, 08:51 PM   #16
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
RIAA Response question
Perhaps you will find this useful; an RIAA inverse EQ implemented in a dependent source using a laplace transform in LTSpice.

LAPLACE= (1+3.18e-3*s)*(1+7.5e-5*s)/(1+3.18e-4*s)
Attached Images
File Type: png laplace transform for Inverse RIAA.PNG (47.5 KB, 266 views)
__________________
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
  Reply With Quote
Old 1st August 2015, 08:52 PM   #17
rayma is online now rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Quote:
Originally Posted by paba View Post
you have small errors in inverse circuit and in DUT accumulated no?
Sure, all experiments have various error sources, that's part of science. But, you can estimate the errors from each source, add them,
and estimate the worst case error. Ideally that should be significantly less than your desired spec. (For large numbers of circuits
you would use a more statistical method, but your particular parts may not be close to the average.) I hand select all
my RIAA parts to 0.1% or better, and then make matched pairs of each for good tracking between channels.
  Reply With Quote
Old 1st August 2015, 10:23 PM   #18
rayma is online now rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Quote:
Originally Posted by Conrad Hoffman View Post
IMO, with inexpensive equipment you can build a more accurate inverse RIAA circuit than you can directly measure
RIAA response. With the inverse filter you can also look at square wave response, which makes errors stand out like a sore thumb.
I've also found that this method works well. Just select your inverse RIAA parts carefully for a close tolerance.
  Reply With Quote
Old 1st August 2015, 11:14 PM   #19
scott wurcer is offline scott wurcer  United States
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: limbo
Quote:
Originally Posted by pos View Post
I am currently implementing a RIAA deemphasis EQ preset in rePhase, but the data I have is not reliable enough.
Could you please export this curve as a 3-column file (frequency, magnitude, phase) with a high frequency range (say 1Hz-100kHz) and high resolution?
I did a minimum phase RIAA (5440 coefficients @96K) for my article in the next Linear Audio, ~.00001dB and .00002 degree even at 20Hz without using any windowing.
__________________
"The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important."

Last edited by scott wurcer; 1st August 2015 at 11:16 PM.
  Reply With Quote
Old 2nd August 2015, 11:11 AM   #20
Calvin is offline Calvin  Germany
diyAudio Member
 
Calvin's Avatar
 
Join Date: Nov 2004
Location: close to Basel
Hi,

here´s the inverting Riaa schematic I use.
It has the Neumann EQ included and features three switches per channel to switch between MM(-40dB) and MC(-60dB) and between four source impedance values (0R, 50R, 550R and 600R).
I used serial and parallel connected parts to reduce tolerances.
Resistors are Metal film 0207-size and Caps are Mica, 1%, all sourced from Reichelt.de.
The PCB is housed in a small HF-aluminum casing.
Just feed the input connectors with a signal from a signal generator, or CD-Player and connect the output to Your phono-stage input.
Besides control listening, You can check amplitude- and square wave response.

jauu
Calvin

btw. the asc I attached earlier has the anti-Riaa implemented.
Just use that one for Your own sims to see deviations from the ideal linear response.
Attached Images
File Type: jpg inv RIAA-Neumann sch.jpg (149.6 KB, 255 views)
File Type: jpg inv RIAA-Neumann brd.jpg (81.6 KB, 209 views)
File Type: jpg inv RIAA-Neumann print.jpg (80.8 KB, 203 views)
  Reply With Quote

Reply


RIAA Response questionHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
What is a good RIAA Square Wave Response? andyr Analogue Source 24 4th May 2017 03:45 PM
Factoring cartridge response into RIAA Brinkman Analogue Source 29 21st April 2014 11:28 PM
RIAA Question - Power DIYspaceW Tubes / Valves 6 7th September 2012 04:53 PM
RIAA curve question? Sunsun22 Analogue Source 13 29th December 2010 07:28 PM
Question about the pearl RIAA stage lordvader Pass Labs 25 20th December 2006 12:02 AM


New To Site? Need Help?

All times are GMT. The time now is 02:25 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki