RLC Filter for low pass filtering of the TDA1543? - diyAudio
Go Back   Home > Forums > Source & Line > Digital Line Level

Digital Line Level DACs, Digital Crossovers, Equalizers, etc.

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 6th August 2014, 02:50 PM   #1
freax is offline freax  Australia
diyAudio Member
 
freax's Avatar
 
Join Date: Sep 2007
Location: NSW
Default RLC Filter for low pass filtering of the TDA1543?

Hi, I'm looking to nail the low pass filtering of a TDA1543 to a lower frequency (say 18-22kHz) with the use of an RLC low pass circuit, I was wondering if anyone would be able to help me with some values for the coil resistor and capacitor. (I'm no expert.)

http://sim.okawa-denshi.jp/en/RLCtool.php

The values that I get are:
680kOhm for resistor
0.00238 H for the coil
with 0.022uF for the capacitor.

How would I go at winding the coil?

This would be a part of a passive I/V conversion process for the output.

Coupling capacitors are a K73-15B with a value of 0.022uF

Resistors would need to be of a sufficient value to provide 1-2v RMS output.

What would be the effect on the waveform of adding impedance (ie from a choke) to the output of a simple 16 bit non oversampling DAC with passive IV conversion? ex: TDA1541/1543

Would also be interested/curious as to what would happen to the waveform.

Thank you for your time.
__________________
"It seems that perfection is reached not when there is nothing left to add, but when there is nothing left to take away" - Antoine de Saint Exupéry

Last edited by freax; 6th August 2014 at 02:59 PM.
  Reply With Quote
Old 7th August 2014, 02:35 AM   #2
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Blog Entries: 100
Send a message via MSN to abraxalito Send a message via Yahoo to abraxalito Send a message via Skype™ to abraxalito
From a quick sim on LTSpice, I get the following component values

R = 500R - this is the I/V resistor
L = 18mH
C = 3.3nF

You'll also need a resistor on the output, across the cap to provide dampling. This is 3k.

This is a very rough and ready first pass as aspects like the inductor's AC losses haven't been factored in. I've also assumed that it will feed into a high impedance load (no less than 47k). The load impedance has an impact on the damping and hence ringing.

You don't need to wind your own coil, Mouser has suitable 18mH chokes - http://www.mouser.com/ds/2/54/FSR1013-72226.pdf
__________________
When you design something for other people you don't have as much motivation to make it beyond excellent - Woz
  Reply With Quote
Old Yesterday, 12:31 AM   #3
freax is offline freax  Australia
diyAudio Member
 
freax's Avatar
 
Join Date: Sep 2007
Location: NSW
Quote:
Originally Posted by abraxalito View Post
From a quick sim on LTSpice, I get the following component values

R = 500R - this is the I/V resistor
L = 18mH
C = 3.3nF

You'll also need a resistor on the output, across the cap to provide dampling. This is 3k.

This is a very rough and ready first pass as aspects like the inductor's AC losses haven't been factored in. I've also assumed that it will feed into a high impedance load (no less than 47k). The load impedance has an impact on the damping and hence ringing.

You don't need to wind your own coil, Mouser has suitable 18mH chokes - http://www.mouser.com/ds/2/54/FSR1013-72226.pdf

Thank you very VERY much for that.

I like to pretend that I live here so I usually don't buy stuff from reputable component outlets:
Attached Images
File Type: jpg tumblr_inline_mww19o9IBM1qboqbv.jpg (171.4 KB, 15 views)
__________________
"It seems that perfection is reached not when there is nothing left to add, but when there is nothing left to take away" - Antoine de Saint Exupéry
  Reply With Quote
Old Yesterday, 01:05 AM   #4
diyAudio Member
 
Join Date: Jun 2003
Location: Hamilton, was Ottawa (Canada)
Classics, I L O V E old school!

You should start at NOS and work your way up!:

Old T:

TDA1543_Analog_Stage.gif


and New CarlosFM

CarlosFM 1543 NOS high z.jpg

DIYHiFi.org • View topic - Understanding DSD

CarlosFM NOS_Sin(x)_passive_compensation.jpg

These are low z and high z for 1543 and NOS sinc rolloff correction.

PS CarlosFM also made a TINA opamp that was 2nd order and peaked at 20k for NOS sinc correction and then dropped like a stone .... (I'll let someone with better googleFU find it)

Last edited by AudioLapDance; Yesterday at 01:27 AM.
  Reply With Quote
Old Yesterday, 01:22 AM   #5
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Blog Entries: 100
Send a message via MSN to abraxalito Send a message via Yahoo to abraxalito Send a message via Skype™ to abraxalito
From my memory of the NOS droop that graph looks overly 'hot' (i.e. applies too much lift). I've played with an LC LP filter which rings up and found a closer match to the required curve comes from setting the resonance a tad higher in frequency. But then I'm only interested in correcting up to 18kHz as my hearing's shot beyond that for sure....
__________________
When you design something for other people you don't have as much motivation to make it beyond excellent - Woz
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
PCM63 Low Pass Filtering Arno Pf Digital Source 2 11th July 2013 10:11 AM
Time domain interpolation instead of the usual low pass filtering? mr_push_pull Digital Source 13 30th March 2011 11:19 AM
DIY One fader mixer with Filter Low Pass, Hi Pass, Notch Pass Filter PGM stevep314 Analog Line Level 0 10th August 2010 09:15 PM
Help with Subwoofer amp Low-Pass Filtering EWorkshop1708 Subwoofers 4 19th May 2009 05:51 PM
RLC Filter for Delta 12 LF PTSOUNDLAB Multi-Way 17 7th August 2002 07:45 PM


New To Site? Need Help?

All times are GMT. The time now is 05:16 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2