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

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Soundcard interface.
Soundcard interface.
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 7th July 2005, 07:51 PM   #1
Mr Evil is offline Mr Evil  United Kingdom
diyAudio Member
 
Join Date: Aug 2004
Location: Behind you
Default Soundcard interface.

A device to make a soundcard more useful as a measuring instrument: http://www.cheese83.freeserve.co.uk/amp/scope.htm


Perhaps someone has some ideas for a better bandpass filter? Something that uses more reasonable component values, ideally small enough to wire p2p between the sockets, like the current one.
Attached Images
File Type: jpg front.jpg (44.6 KB, 244 views)
__________________
https://mrevil.asvachin.eu/
  Reply With Quote
Old 7th July 2005, 07:54 PM   #2
SY is offline SY  United States
On Hiatus
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Soundcard interface.
Thought about a gyrator to replace the inductor?
__________________
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote
Old 7th July 2005, 08:00 PM   #3
jan.didden is offline jan.didden  Europe
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Westende Resort, BE coast
SY,

You been to the beauty farm? Your avatar looks even younger than me!

Jan Didden
__________________
Cable: a potential source of trouble interconnecting two other potential sources of trouble - Erik Margan
Linear Audio pubs and articles . The SilentSwitcher now at diyaudio store SilentSwitcher. Keeping in touch with SY.
  Reply With Quote
Old 7th July 2005, 08:05 PM   #4
SY is offline SY  United States
On Hiatus
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Soundcard interface.
Difference is, mine is dead.
__________________
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote
Old 8th July 2005, 02:23 AM   #5
Mr Evil is offline Mr Evil  United Kingdom
diyAudio Member
 
Join Date: Aug 2004
Location: Behind you
Quote:
Originally posted by SY
Thought about a gyrator to replace the inductor?
That's a possibility. An op-amp with twin-T notch filter feedback would also work, but before I try anything like that I want to try to find a passive solution since that will introduce the least noise, and if I can avoid inductors (or at least use only air-core ones) then distortion will likely be lower too. It's unfortunate that there is no bandpass equivalent to the twin-T (as far as I know).
__________________
https://mrevil.asvachin.eu/
  Reply With Quote
Old 12th July 2005, 11:38 PM   #6
Mr Evil is offline Mr Evil  United Kingdom
diyAudio Member
 
Join Date: Aug 2004
Location: Behind you
I've been doing some experiments with bandpass filters trying to improve the resolution of distortion measurements and have come to the conclusion that the -96dB 2nd harmonic I see is actually the distortion of the soundcard's input, not the output. Thus it will never be able to measure anything lower than that directly. I should have paid more attention to your notch filter suggestion, SY...

After playing around with a notch filter in place, I reckon I could get maybe 20dB improvement, which would mean the noise floor would become the limiting factor.

My findings on bandpass filters are:
  • Passive LC: Very high Q. Very high distortion.
  • LC with L replaced by gyrator: Low Q. Low distortion.
  • Op-amp with twin-t feedback: High Q. Low distortion. Stability problems.
  • Passive RC: Very low Q. Very low distortion.
__________________
https://mrevil.asvachin.eu/
  Reply With Quote

Reply


Soundcard interface.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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Which cap to buy for DAW interface mod? chriswww Parts 1 24th February 2009 02:30 PM
HDD to I2s interface elnec Digital Line Level 6 15th September 2008 08:43 PM
USB interface NOS DAC?? sbrtoy Digital Source 25 7th May 2007 05:14 PM
interface I2S with USB mermoz Digital Source 0 21st February 2003 10:34 AM


New To Site? Need Help?

All times are GMT. The time now is 08:49 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki