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

Class D Switching Power Amplifiers and Power D/A conversion

TDA8954 at 4ohms bridge
TDA8954 at 4ohms bridge
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 18th September 2016, 07:36 AM   #1
alarrr is offline alarrr  Estonia
diyAudio Member
 
Join Date: Mar 2016
Default TDA8954 at 4ohms bridge

There is a note that those stereo half bridges of that chip can be made to full bridge mono. At 8 ohms with 420 watt of power. Now I want to connect 4 ohm speaker there.
It should just take lower voltage to reach that 420watts and not to hit current limit. Current plans would be feed it with 30+-(maybe it needs even less?).

What ya think? Will it instantly explode? Would it work?


http://www.nxp.com/documents/data_sheet/TDA8954.pdf
  Reply With Quote
Old 18th September 2016, 01:32 PM   #2
DUG is offline DUG  Canada
diyAudio Member
 
Join Date: Jan 2003
Location: mississauga ontario canada
Current limit of 12A and each drive would see 2R.

4R speaker impedance curve would dip below 4R. This would make the current limit come on even sooner.

So at 8R BTL they can run +/-42V.

For 4R BTL perhaps +/-21V might be a good start.

IMHO
__________________
Doug We are all learning...we can all help
"You can't stop the signal, Mal. Everything goes somewhere..."
  Reply With Quote
Old 19th September 2016, 07:26 PM   #3
Pafi is offline Pafi  Hungary
diyAudio Member
 
Join Date: May 2004
Location: Budapest
DUGs calculation is correct.

Maybe you can get a little extra power with 24...30 V PSU this way at the expense of doubled loss compared to single channel single ended operation.

The protection will prevent explosion, but there is not much benefit.
  Reply With Quote
Old 20th September 2016, 06:01 AM   #4
alarrr is offline alarrr  Estonia
diyAudio Member
 
Join Date: Mar 2016
There is a few things I noticed. Tda7498E gives 160 watts at +36V and it's full bridge.
Tda8954 at voltage diffrence +/-21V total swing diffrence 42V, 420W? Something dosen't match up here
  Reply With Quote
Old 20th September 2016, 06:09 AM   #5
Pafi is offline Pafi  Hungary
diyAudio Member
 
Join Date: May 2004
Location: Budapest
Yes. You will never get 420W into 4 ohm, this is the basic problem.

As I wrote little extra power with 24...30 V PSU this way at the expense of doubled loss compared to single channel single ended operation. Probably 250W.
  Reply With Quote
Old 20th September 2016, 06:13 AM   #6
Pafi is offline Pafi  Hungary
diyAudio Member
 
Join Date: May 2004
Location: Budapest
V=I*R. P=V*I. Effective voltage (and current) is 0.71*peak Voltage. Calculate!
  Reply With Quote
Old 20th September 2016, 06:55 AM   #7
alarrr is offline alarrr  Estonia
diyAudio Member
 
Join Date: Mar 2016
Would those irs2092 driven work better=?

NEW Assembled HIFI Stereo IRS2092 Class D Power amplifier board 345W+345W

FULL BRIDGE! Voltage is in acceptable limits. There isnt much written about it.
  Reply With Quote
Old 20th September 2016, 07:30 AM   #8
alarrr is offline alarrr  Estonia
diyAudio Member
 
Join Date: Mar 2016
Quote:
Originally Posted by alarrr View Post
Would those irs2092 driven work better=?

NEW Assembled HIFI Stereo IRS2092 Class D Power amplifier board 345W+345W

FULL BRIDGE! Voltage is in acceptable limits. There isnt much written about it.
Actually never mind. If Ill gona put over 100 dollars on amplifier I could add another 100 and get properly built one.
Skytec Sky 3000 MKII Professional PA Amplifier Mobile Party DJ Power Amp 3000W | eBay
  Reply With Quote
Old 20th September 2016, 06:36 PM   #9
Pafi is offline Pafi  Hungary
diyAudio Member
 
Join Date: May 2004
Location: Budapest
Quote:
Originally Posted by alarrr View Post
Would those irs2092 driven work better=?

NEW Assembled HIFI Stereo IRS2092 Class D Power amplifier board 345W+345W

FULL BRIDGE! Voltage is in acceptable limits. There isnt much written about it.
Who do you write to and why?!?

CURRENT LIMIT! Peak current for 400 W @ 4 ohm is higher than the ICs built in limit.

Physics is the same.

Just buy a complete one, good idea!
  Reply With Quote
Old 21st September 2016, 06:15 PM   #10
Th3 uN1Qu3 is offline Th3 uN1Qu3  Romania
diyAudio Member
 
Join Date: Feb 2010
Location: Bucharest
Send a message via Yahoo to Th3 uN1Qu3
That Skytec amp is junk btw, you are better off getting bigger modules and an amplifier chassis from ebay and building it yourself...
__________________
"Audio grade" components simply means that they failed at a more critical job.
  Reply With Quote

Reply


TDA8954 at 4ohms bridgeHide 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
TAS5630B vs TDA8954 bimbla Class D 14 8th July 2018 01:44 PM
TDA8954 output filter riktw Class D 43 21st August 2017 08:48 PM
TDA8954 input capacitor snowcatmaiden Class D 1 8th July 2016 08:45 AM
Behringer Sub TDA8954 repair Alexander Baev Class D 12 30th November 2015 07:00 AM
100w into 4ohms? Powertimes_2 Solid State 4 1st December 2008 11:50 PM


New To Site? Need Help?

All times are GMT. The time now is 10:36 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki