Breadboard amp = echoes + highpass filter? - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 12th April 2011, 12:37 PM   #1
diyAudio Member
 
Join Date: Jan 2011
Default Breadboard amp = echoes + highpass filter?

Heya guys, I'm not sure where to post this, but its really frustrating me to no end.

I have a breadboard (shoot me) and I currently have a very basic push-pull amp on it.

Now, the amp works perfectly fine as long as I have the oscilloscopes ground connected (the probe makes no difference) to it.

If this is not connected then the amp will do two things:
-Sound echo'y
-Lose lower frequency audio (inc voices)

I tried this circuit with both batteries and a 12DC supply form the wall, both have the same result.

Now, I had a PWM infra red transmitter on it previously and this experienced the same problem with the receiver missing audio frequencies!

I checked the signal and it seems to experience this change (when disconnecting the. oscilloscope) right after the opamp providing voltage amplification (inverting opa2227). (though it still happens without the op amp)

Thanks for any suggestions, I'll try another breadboard soon!
  Reply With Quote
Old 12th April 2011, 01:08 PM   #2
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
It seems the scope probe (earthing clip) is providing an "earth" that is somehow missing.

Have you missed out a return route for one or more of your currents?
__________________
regards Andrew T.
  Reply With Quote
Old 12th April 2011, 01:50 PM   #3
diyAudio Member
 
Join Date: Jan 2011
You're right, I had another talk with my Dad about it and I found the problem.

It was the 3.5 mm connector I was using. I was only using one channel of the stereo, but instead of ground and one of the channels, I was listening to the difference between left and right.

This explains the echoing and the grounding.

Thanks for the help.
  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
1st order Highpass filter to cap cone excursion? Boscoe Multi-Way 0 12th December 2010 11:15 AM
Highpass filter via feedback cap scottw Chip Amps 12 24th October 2009 12:20 PM
Active highpass filter - ground skogs Analog Line Level 3 19th June 2007 07:25 PM
Measuring tweeter FR without a highpass filter owdi Multi-Way 3 14th March 2007 06:40 AM
Highpass filter using sound card??? vsboxerboy Digital Source 0 18th July 2005 09:59 AM


New To Site? Need Help?

All times are GMT. The time now is 09:12 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