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

Solid State Talk all about solid state amplification.

high gain 2nd order high pass active filter topology
high gain 2nd order high pass active filter topology
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
Thread Tools Search this Thread
Old 22nd March 2006, 07:18 PM   #21
consort_ee_um is offline consort_ee_um  United Kingdom
diyAudio Member
Join Date: May 2004
Location: Hertfordshire
Here is a circuit which conforms to the above It gives 6db of boost on a gain of 27dB. The ratio of R1 and R2 defines the amount of boost. Can use any power op-amp with the proviso that the input resistance is high. ST quote 5Mohms for the TDA2030A. The naughty people at National do not quote an input resistance for the LM3866 but they do say in the notes that a 100k resistor across the input defines the input resistance as 100K thus implying the resistance is high enough not to affect the filter.
This circuit in combination with an underdamped vented box design would make a better sub-woofer IMHO than the popular closed box and Linkwitz transform design. It will have lower cone excursion and voice coil temperature for the same acoustic power.
Attached Images
File Type: jpg boost.jpg (13.1 KB, 198 views)
  Reply With Quote
Old 23rd March 2006, 01:26 AM   #22
djk is offline djk
diyAudio Member
djk's Avatar
Join Date: Feb 2001
Location: USA
Nice to see a drawing of what I said in post #8

Post #8
Just pretend the feedback node of the power amp is the output node of a unity gain opamp. If the lower arm feedback resistor is low enough then you won't have any problems.

If the lower arm feedback resistor is a high value, then just add a voltage divider at the output of the amp that has the same ratio as the feedback resistor pair. Sony did this around a 30dB preamp line stage, works fine.

The NAD 3020 integrated amp uses this on the main power amp input too, the lower arm feedback resistor is 27R.
  Reply With Quote


high gain 2nd order high pass active filter topologyHide 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
Active High-pass filter for Horn Subs Eddie Wolve Parts 5 21st July 2009 05:47 PM
3rd order HIgh pass filter - explanation? APaddy Analog Line Level 12 24th January 2006 08:06 AM
Low/High Pass Filter fatpower17 Car Audio 1 28th June 2004 08:45 AM
Low- vs. High- Order Active Crossover askbojesen Multi-Way 9 8th October 2003 03:50 PM
Aleph P.17 1st order high pass filter Ignatz Pass Labs 2 30th October 2002 06:56 PM

New To Site? Need Help?

All times are GMT. The time now is 03:41 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio