TDA7386 Problem - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 August 2012, 03:11 AM   #1
diyAudio Member
 
Join Date: Aug 2012
Default TDA7386 Problem

Hey all,

I'm currently working on a project that consists of taking a line level input from something like an iPod and play it out some speakers. I'm having a problem with the subwoofer and woofer, whenever there are really low notes they must short or something causing the power supply to current limit. I have concluded that it's the woofer/subwoofer because without them connected it works fine.

As for the circuit, I have the line level input coming into 4 sallen-key active filters. For the subwoofer, there is a lowpass filter with a 3db cutoff point @ 200Hz, tweeter has a high pass filter with 3db @ 5KHz, Mid-Range has a band-pass (high pass + low pass in series), and woofer has a band-pass (high pass + low pass in series) with 3dB cutoffs @ 100Hz - 1KHz.

The filters look very good when viewing through an o-scope and scanning through the frequencies. There is no distortion and the 3dB cutoff points are perfect.

From the filters, the signal travels into a TDA7386 chip which is a 4 channel 45 Watt amplifier which then goes out to the 4 respective speakers (35W rated, 4 ohm). I'm not sure if I don't have enough decoupling caps or if I'm doing something wrong with the amplifier chip.

I am following the exact circuit layout from the datasheet, with one exception which is pulling the mute and st-by to Vcc. When everything is working well, the power supply gets roughly 0.5A (at a more than reasonable volume) pulled. I'm using a 12V power supply (benchtop lab power supply) that has a current limit of 5A which keeps activating when it's operating (only during loud bass notes it seems).

Any help would be very much appreciated.
  Reply With Quote
Old 12th August 2012, 12:41 PM   #2
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
I never recommend a regulated supply for a power amp.
I think you are hitting the very reason that I refuse to use regulated or current limited PSU on any of my power amps.

The problem is that fast signals into speakers demands very high instananeous peak currents from the PSU to the speaker.
A 5A PSU is almost certainly collapsing when the peak demand hits it's limit.

I recommend you build a linear non regulated PSU for your 4 channel amplifier.
Buy a transformer + bridge rectifier + some smoothing capacitors. That's all you need to get your amp working.
__________________
regards Andrew T.
  Reply With Quote
Old 12th August 2012, 01:18 PM   #3
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Blog Entries: 101
Send a message via MSN to abraxalito Send a message via Yahoo to abraxalito Send a message via Skype™ to abraxalito
What AndrewT says. If you add up all your amp wattage it comes to 180W RMS or 360W peak. Your PSU is 60W peak. You might get away with a 60W PSU if you had a very large electrolytic capacitor on its output (say 47,000uF). Safer though to go for a PSU giving 15A.
__________________
No matter if we meanwhile surrender every value for which we stand, we must strive to cajole the majority into imagining itself on our side - Everett Dean Martin
  Reply With Quote
Old 12th August 2012, 01:38 PM   #4
diyAudio Member
 
Join Date: Aug 2012
Alright, appreciate the help gentlemen. I'll give that a try and let you know.
  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
Help with TDA7386 jorge_rc Chip Amps 8 20th June 2012 07:46 PM
TDA7386 Problem jorge_rc Chip Amps 6 15th April 2009 06:32 PM
TDA7386 Problem please help Brownstocker Chip Amps 5 28th January 2008 10:02 PM
Tda7386 koloko Chip Amps 1 18th June 2007 08:25 AM
Problem with TDA7386 SideWinder Chip Amps 0 24th May 2004 10:13 AM


New To Site? Need Help?

All times are GMT. The time now is 07:01 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