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

Crazy!! Music from inside the Amplifier!!
Crazy!! Music from inside the Amplifier!!
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 5th September 2020, 06:07 PM   #1
Ampgutz is offline Ampgutz  United States
diyAudio Member
 
Join Date: Jul 2020
Location: Boone, North Carolina
Default Crazy!! Music from inside the Amplifier!!

I am bench testing a Skar lp-80.4 and when I turn up the gain to max I can hear music from the pcb. I have isolated it to channels 3/4. How is this possible. Something has to move 20times per sec to create sounds correct? I can clearly hear vocals! Someone help me please!!
  Reply With Quote
Old 5th September 2020, 06:50 PM   #2
deChrLam is offline deChrLam  Switzerland
diyAudio Member
 
Join Date: Feb 2012
Radio station nearby. I remember as a kid I could hear the radio in the analogue telephone
  Reply With Quote
Old 5th September 2020, 06:52 PM   #3
Ampgutz is offline Ampgutz  United States
diyAudio Member
 
Join Date: Jul 2020
Location: Boone, North Carolina
No, it is playing the music that I am feeding into the rca inputs
  Reply With Quote
Old 5th September 2020, 06:53 PM   #4
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Crazy!! Music from inside the Amplifier!!
Many amplifiers (not just class D) can produce audible sound from various components such as power transistor etc. A Class D will have coils and filters on the output stages, all can 'sing'.
  Reply With Quote
Old 5th September 2020, 07:01 PM   #5
MarcelvdG is offline MarcelvdG  Netherlands
diyAudio Member
 
Join Date: Mar 2003
Location: Haarlem, the Netherlands
It could be an inductor or a class II ceramic capacitor that acts as a loudspeaker. Inductors and transformers can produce sounds due to an effect called magnetostriction (see Magnetostriction - Wikipedia ), ceramic class II capacitors due to piezoelectricity ( Piezoelectricity - Wikipedia ).

Last edited by MarcelvdG; 5th September 2020 at 07:02 PM. Reason: I asked a question that was already answered before I posted it.
  Reply With Quote
Old 5th September 2020, 07:09 PM   #6
Ampgutz is offline Ampgutz  United States
diyAudio Member
 
Join Date: Jul 2020
Location: Boone, North Carolina
With the amp on and no speaker hooked up with music playing into the rca inputs it is playing the music I am inputting from the pcb on the output section of the amp. The amp is a class ab with no inductors on the output section of the amp.Click the image to open in full size.
  Reply With Quote
Old 5th September 2020, 07:17 PM   #7
MarcelvdG is offline MarcelvdG  Netherlands
diyAudio Member
 
Join Date: Mar 2003
Location: Haarlem, the Netherlands
Then this is the wrong subforum.
  Reply With Quote
Old 5th September 2020, 07:18 PM   #8
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Crazy!! Music from inside the Amplifier!!
It's a common phenomenon and I've noticed it myself. Power transistors do this but whether it is the junction itself or something mechanical* and perhaps related to how its mounted I don't know.

* ultimately something mechanical has to be occurring somewhere to move the air in relation to the electrical signals and thus produce the sound that we hear.

It is common though.
  Reply With Quote
Old 5th September 2020, 07:20 PM   #9
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Crazy!! Music from inside the Amplifier!!
Quote:
Originally Posted by MarcelvdG View Post
Then this is the wrong subforum.
Looks like it is a car audio product Marcel. I'll move it.
  Reply With Quote
Old 5th September 2020, 07:40 PM   #10
Perry Babin is offline Perry Babin  United States
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
I'll vote for transformer as well. This often happens when there are loose windings. It also seems to be more common in amps with regulated power supplies. Sometimes, touching the windings can make a difference.

Audio, especially vocals, is higher than 20Hz. It's more in the range of 400-1kHz.
__________________
Anyone who purchased the repair tutorial, email me (babin_perry@yahoo.com) if you want to download the latest version.
  Reply With Quote

Reply


Crazy!! Music from inside the Amplifier!!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
Bose Wave Music Syst. Ultimate Sound? Gallery from inside Devices - Serv. Man. wanted tiefbassuebertr Solid State 59 28th April 2019 06:12 PM
Testing an amp with dummy load, can hear music coming from inside the amp. ElectroAcoustic Solid State 11 10th December 2014 10:43 PM
Amplifier distortion with music signal (measurements inside) mr_push_pull Everything Else 80 26th June 2013 11:44 AM
Something INSIDE THE AMP playing music Faster7 Car Audio 2 10th September 2010 01:47 PM
A crazy idea? Rebuilding PS computer for music server legarem Digital Source 3 25th June 2009 11:59 PM


New To Site? Need Help?

All times are GMT. The time now is 07:39 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki