Sub Amp, what's wrong? - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

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 25th August 2006, 03:49 PM   #1
diyAudio Member
 
Join Date: Apr 2005
Location: New Jersey
Default Sub Amp, what's wrong?

When I turned on the receiver that morning, there was no bass sound and the sub amp was very hot. It didn't work at all that day. A few days later I tried it again, and there is sound. The only problem is that there is a initial "pop" sound from the speaker when it comes on. It seems like the amp is sending a larger than normal signal to the driver. The actual driver works fine with a different amp. I want to know what caused the malfunction, and what is wrong with it now? How can I fix the hard "turn on" and restore the soft "turn on"? Seems like a poly switch may have blown.
  Reply With Quote
Old 25th August 2006, 04:02 PM   #2
diyAudio Member
 
mrshow4u's Avatar
 
Join Date: Jul 2006
It sounds like the front-end (op-amp, discrete differential stage) is a little "wiggley", or unstable. The pop might be a little DC offset. See if the cone pushes out, or sucks in. If so, I'd repair it pronto. You don't want the voice coil to sit there and dissipate the amp's wrong doing.
__________________
".........These go to eleven"
  Reply With Quote
Old 25th August 2006, 04:15 PM   #3
diyAudio Member
 
Join Date: Apr 2005
Location: New Jersey
Yes, the cone does push in and/or out. As you can tell, I'm not electronically inclined. Is it hard to repair or replace the op-amp?
I'm using another amp now, but would like to repair this amp. I have had it over a year, but it's been in use only a few months.
  Reply With Quote
Old 25th August 2006, 04:38 PM   #4
diyAudio Member
 
mrshow4u's Avatar
 
Join Date: Jul 2006
It MIGHT be the op-amp, if it exist on that design. First place to start is getting some service information. A schematic would be really handy at this point. It sounds like this problem is intermittent. That's going to make it a little more tricky. Are there random noises coming out of the woofer at idle??? As it is intermittent, my gut feeling tells me it is the front-end (input stage) electronics. If it is an op-amp and is socketed, you could try to replace it. Mind your pin one. It'll be identified by a dot in the upper left corner of the IC. If there is no dot, look for a notch in the plastic package. Pin one will be left of that. If the above scenario takes place, DISCONNECT the speaker the first time you turn it on. Measure the speaker leads and check for DC. Anything under 50mV, or so is allright. Anything above (especially 5 ~ 60VDC) and you've still got work to do. Do not reconnect the speaker. If you get the service info, plenty of people will give you helpful information to to get your thumping back. Good luck

Jon
__________________
".........These go to eleven"
  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
Wrong Voltage / current on BoZ... or Wrong Measuring ? gionag Pass Labs 8 14th May 2008 11:24 AM
what's wrong with it? bravesz Digital Source 6 27th September 2006 08:15 AM
something wrong? spyder6 Subwoofers 2 21st February 2005 06:58 PM


New To Site? Need Help?

All times are GMT. The time now is 01:09 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