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.

Emotiva UPA-500 Distorted Channels
Emotiva UPA-500 Distorted Channels
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 17th January 2020, 11:47 PM   #11
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Do the bad channels have any DC output voltage? Do you even need the bad channels anyway?

Last edited by rayma; 18th January 2020 at 12:10 AM.
  Reply With Quote
Old 18th January 2020, 12:05 AM   #12
llwhtt is offline llwhtt  United States
diyAudio Member
 
Join Date: Jun 2008
Location: SoCal
You''ll probably have to ask Emotiva for one, fingers crossed.

Craig
  Reply With Quote
Old 18th January 2020, 04:54 PM   #13
AlexRivera is offline AlexRivera
diyAudio Member
 
Join Date: Jan 2017
Location: Texas
Quote:
Originally Posted by rayma View Post
Do the bad channels have any DC output voltage? Do you even need the bad channels anyway?


Iím glad you asked, I didnít measure this before!!

Yes, the bad channels have DC output, one has 876mV and the other 650mV, all others have anywhere from 15 to 65 mV.
  Reply With Quote
Old 18th January 2020, 05:33 PM   #14
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Quote:
Originally Posted by AlexRivera View Post
the bad channels have DC output, one has 876mV and the other 650mV, all others
have anywhere from 15 to 65 mV.
Might be leaky electrolytic capacitors. A bad transistor probably would cause much more DC output.
There may be more problems than capacitors, if you get no sound in those channels.
See if you can get a schematic, it would help a lot.

Last edited by rayma; 18th January 2020 at 05:36 PM.
  Reply With Quote
Old 22nd January 2020, 11:05 PM   #15
AlexRivera is offline AlexRivera
diyAudio Member
 
Join Date: Jan 2017
Location: Texas
Quick Update,

I tried finding a schematic but nothing, Emotiva didn't even respond (yet) my email where I asked about the price for the repair which should be very easy since they have a fixed price policy.

So I did remove the electrolytic caps for that channel and tested them, they were all good, even then I replaced them with new Nichicon caps and nothing the problem was still there, then I removed the output transistors to check them and they were also good, not even leakage, so when I soldered them back, voila.... no DC offset, it went down to 1.1 mV, then I tested with the speakers and no distortion.... Cold solder huh???

I tried re-heating the solder in the other channel's output transistors but distortion is still there, DC offset is gone too, that channel is also down to 1.1 mV.

I will keep looking around and re-heating solder here and there and see what happens.

I will also run the 1kHz sine wave and analyze it with the scope like I did before and see what happens.

Cheers!
  Reply With Quote
Old 22nd January 2020, 11:06 PM   #16
rayma is offline rayma  United States
diyAudio Member
 
Join Date: Apr 2011
Good work, keep at it but be careful and don't get discouraged.
  Reply With Quote

Reply


Emotiva UPA-500 Distorted ChannelsHide 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
Orion HCCA 425 pop top all 4 channels heavily distorted Chopperbuilder Car Audio 5 5th August 2019 06:34 AM
NAD C370 distorted sound on both channels nemz Solid State 5 24th September 2017 06:48 AM
Bryston 6B original - Overheating channels, distorted output cbox83 Solid State 4 10th September 2017 12:01 AM
3 out of 4 channels are distorted nonprof Car Audio 20 24th February 2016 06:14 AM
Latest project, guitar amp with clean/distorted channels. nigelwright7557 Instruments and Amps 1 28th July 2015 08:07 PM


New To Site? Need Help?

All times are GMT. The time now is 03:11 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