SMSL T-AMP problem - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

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 January 2013, 07:47 AM   #1
diyAudio Member
 
Join Date: Feb 2012
Default SMSL T-AMP problem

Hi i have a SMSL T-AMP model SA-50. I just accidently touching my RCA + plug with the speaker output of the AMP, i heared a little pop sound from my speaker.

Then i notice my left speaker volume is much softer than right side, it is very much lack of low frequency (less bass and deep vocal).

1. It is not speaker issue because i have swap left and right and the problem is still on the left.
2. It is the problem on the left speaker output

Can anyone point out which part of the amp possibly spoil and is it possible to repair? or i just get a new one.
  Reply With Quote
Old 5th January 2013, 04:53 PM   #2
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007


Moved to Class D

__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.
  Reply With Quote
Old 5th January 2013, 05:01 PM   #3
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Looking at the data sheet for the TDA7492 I suspect you have zapped the chip. Although it claims to be short circuit proof I'm not so sure about a short to ground (with it being a bridge type output) which is probably what happened with your RCA short. I can't see any of the output chokes going OC but I guess you should do some basic checks.

The circuit should be very similar to this,
http://www.st.com/internet/com/TECHN...CD00205863.pdf
__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.
  Reply With Quote
Old 6th January 2013, 03:16 AM   #4
diyAudio Member
 
Join Date: Feb 2012
So in short it is something wrong in the tda7492 chip which is better for me to get new amp or am I able to just replace the chip ? Can recommend where to get such replacement part ?

I'm no experience in amp diagnose, but I have an oscilloscope can you show me some guide ?
  Reply With Quote
Old 6th January 2013, 06:48 AM   #5
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
The chip should be widely available. The problem will be whether you are able to replace an SMD device successfully,

TDA7492 - STMICROELECTRONICS - IC, AMP, AUDIO, CLASS D, 36POWERSO | Farnell United Kingdom

All you can do for faultfinding is check that your accidental short hasn't caused any print to go open circuit or one of the coils to go open.
__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.
  Reply With Quote
Old 6th January 2013, 09:18 AM   #6
diyAudio Member
 
Join Date: Feb 2012
I just found out that the prob is not with my amp, but the apple airport express that I use to connect to the amp.

Looks like the short circuit protection is real but it is the airport express doesn't have protection. Ill send for warranty then. Thanks Mooly for your expert thought
  Reply With Quote
Old 6th January 2013, 10:00 AM   #7
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
So it's zapped the source, an unusual issue.
__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.
  Reply With Quote
Old 6th January 2013, 10:57 AM   #8
diyAudio Member
 
Join Date: Feb 2012
Because I use rca splitter to subwoofer. When I took out one of my speaker wire and accidentally touching a rca cable and that goes my airport express.

So lesson learn, power off everything before dismantle anything
  Reply With Quote
Old 7th January 2013, 02:01 AM   #9
diyAudio Member
 
Join Date: Feb 2012
I confirm out this by using my iphone or ipod as source and the sound is balanced and work perfectly like before.

Now the problem is in the airport express, howeve when i plug an earphone to the express i can't detect any problem, vocal is just centered and sounded good.

It only happened when i plug to smsl amp and earphone pick up the signal nicely, can anyone explain why ?

One of my guess is the airport express line out lost of some power on left side which to earphone still sufficient enough ? am i correct ?
  Reply With Quote
Old 7th January 2013, 06:40 AM   #10
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
My guess is you zapped either an opamp output in this airport express do-dah or zapped a series output feed component. You would have to open it up and look.
__________________
-------------------------------------------------------
A simulation free zone. Design it, build it, test it.
  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
Just picked up an SMSL TDA7498 based amp ... to much hiss Tino Chip Amps 1 16th September 2012 01:37 PM
Topping TP-20 Mk2 or SMSL SA-S1? kin0kin Class D 4 6th February 2012 03:39 PM
SMSL SA-36 funnies Psychobiker Chip Amps 1 7th January 2012 02:18 PM
Which T-Amp? SMSL SA-S3 or Topping TP21? TylerDurden Class D 1 17th July 2011 02:42 PM


New To Site? Need Help?

All times are GMT. The time now is 10:21 PM.


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