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

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

Opamp buffer @ active crossover input?
Opamp buffer @ active crossover input?
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 17th December 2016, 12:11 PM   #11
AndrewT is offline AndrewT  Scotland
Join Date: Jul 2004
Location: Scottish Borders
The current draw of an opamp is the datasheet figure for quiescent plus whatever you send to the output.
If you have very light loading and no capacitance to charge/discharge, then the output currents can be very small, leaving the quiescent current as the only significant load for the regulators.

But if you have some capacitance as a load and have lower load impedances, then these can become the dominant load that is passed back to the regulators.
A 10k load driven to 2Vac is only 0.3mVpk from alternate supply rails. Add on the same again for small parasitic capacitance and you have only added 0.6mApk to the quiescent load. Small beer.
But if you had a 2k load driven to 4Vac and significant capacitance, then you can easily have 3 to 4mApk to add to your quiescent values for each opamp.
If there is limited supply rail decoupling at each opamp, then much of those peak currents have to come from the low output impedance of the regulator.
regards Andrew T.

Last edited by AndrewT; 17th December 2016 at 12:13 PM.
  Reply With Quote


Opamp buffer @ active crossover input?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
opamp matching +/- input impedance necessary for buffer? HiFiNutNut Chip Amps 34 29th March 2018 02:48 AM
Opamp input buffer choices tfboy Analog Line Level 31 13th September 2015 12:36 PM
Opamp for active crossover Keruskerfuerst Parts 2 7th June 2007 07:57 PM
Tube differential input/buffer /w opamp output gainclone aletheian Chip Amps 2 23rd August 2005 08:36 AM
Best Opamp for an active crossover? ShinOBIWAN Digital Source 1 21st March 2005 04:08 AM

New To Site? Need Help?

All times are GMT. The time now is 09:53 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