diyAudio - Entries for March 2013
Go Back   Home > Forums > Blogs > abraxalito

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
Old

Active elliptic anti-imaging filter

Posted 20th March 2013 at 03:18 AM by abraxalito
Updated 20th March 2013 at 03:30 AM by abraxalito (Added FR)

Passive filters rock for SQ, no doubt about it but I'm still curious how good sounding an active DAC I/V post filter might be. So I've figured out an almost equivalent FR active version of my 7th order LC elliptic filter. This active elliptic has been designed using LTSpice's FilterCad program giving the pole/zero positions, then the Williams handbook of filter design helped me translate those numbers into a working circuit. Its using what Williams calls the VCVS 2nd order section based on a twin-T network to realize the zeroes.

My first attempt at an active elliptic filter was using gyrators but that proved very hard (practically impossible) to get stable with CFB opamps due to their HF gain peaking. VFB opamps I ruled out at the start for inadequate SQ - its not hard to make gyrators stable with them. Hence this approach which promises to work with CFBs though I'd guess I'll probably need to add series Rs between the stages in practice. Nothing built yet but thought I'd...
Attached Thumbnails
Click image for larger version

Name:	DIYA-active-elliptic-filter.png
Views:	645
Size:	19.2 KB
ID:	922   Click image for larger version

Name:	minQ-elliptic-FR.png
Views:	290
Size:	7.7 KB
ID:	923  
abraxalito's Avatar
diyAudio Member
Views 1149 Comments 12 abraxalito is offline
Old

What is dynamics?

Posted 5th March 2013 at 02:02 AM by abraxalito
Updated 11th March 2013 at 06:35 AM by abraxalito

Fascinating discussion going on about the nature of 'dynamics' over on this thread : http://www.diyaudio.com/forums/multi...nger-what.html

Pano writes (post 1174):

There is a consistency across several decades and cultures that high efficiency speakers sound more dynamic than low efficiency. That's a common subjective assessment, so we might ask "why?"

I'm not going to chip in on that thread because I have bigger fish to fry, but ISTM they're all barking up the wrong tree. That's because the question itself isn't quite posed correctly even though its a great start. Nobody listens to speakers alone, they're always powered by amplifiers. The answer to dynamics lies in amplifiers, not speakers. Put another way 'Its the electronics, stupid!'.

Higher efficiency speakers tax amplifiers (here meaning their power supplies in the main) much less - so there's no way to do an apples-apples comparison...
Attached Thumbnails
Click image for larger version

Name:	nitro-psu-noise-6hexa.png
Views:	218
Size:	8.6 KB
ID:	909  
abraxalito's Avatar
diyAudio Member
Posted in Uncategorized
Views 947 Comments 10 abraxalito is offline
Hide this!Advertise here!

New To Site? Need Help?

All times are GMT. The time now is 11:45 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