tda 7294 power amp - 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 25th November 2010, 08:27 AM   #1
laki101 is offline laki101  Serbia
diyAudio Member
 
Join Date: Dec 2009
Default tda 7294 power amp

I need a power amp for some old high power speakers ( as far as I know about 300W each) that I am probably going to get

now I would probably need about 150 to 200W for them and for what I have seen the tda 7294 looks good for that and most importantly cheap and could easily have that much power in some bridge configuration

now I want to know is the bridge circuit in the datasheet ok and could be used?

and how much power do I get in that bridge config with +/- 35V and a 4ohm speaker ?

and how many VA do I need for that is 250VA enough (cause I have that in my lm3886 amp and I was thinking of using that one before I get the money to buy another one as they dont come cheap)

Last edited by laki101; 25th November 2010 at 08:32 AM.
  Reply With Quote
Old 26th November 2010, 04:14 PM   #2
diyAudio Member
 
Join Date: May 2008
Don't confuse the speaker power rating with the power demand. If you want to use those speakers at home, you will probably need something between 10 and 50 W and only, if you like it really loud.

The bridge circuit in the datasheet is okay. Just check that you have the latest revision of the datasheet.

A BTL amplifier sees half the load, so your 4 Ohm speaker would appear as a 2 Ohm load to each TDA. The datasheet states that the output power is already current limited at 29 V with a 4 Ohm load. With a 2 Ohm load the current limitation would set in at a lower voltage. Heatsinking will also become difficult.

Why don't you wait until you have the speakers and try them with your LM3886 amp? Then decide, if you really need more power.
__________________
If you've always done it like that, then it's probably wrong. (Henry Ford)
  Reply With Quote
Old 26th November 2010, 04:33 PM   #3
laki101 is offline laki101  Serbia
diyAudio Member
 
Join Date: Dec 2009
well I already have 8ohm hi-fi speakers at home for the lm3886 amp so at home they are more than enough

I wanted this to have for parties and stuff like that and will probably be used outdoors a lot so I need as much power as I can pump into them

I will probably make just one channel so 2 tda-s cause they cost like 5euor and the resto of the parts 3-4 so for 10 euros I can make ti and use the speakers and power supply that I have so that I can just see how they work and I also want to make something so it looks cheap and interesting
  Reply With Quote
Old 27th November 2010, 06:55 AM   #4
diyAudio Member
 
Join Date: May 2008
You could try the modular application circuit from the TDA7293 datasheet. That should be capable of delivering more than 100 W into 4 Ohm speakers with 35 V. And the TDA7293 usually costs more or less the same as the TDA7294.

You want it to look cheap?
__________________
If you've always done it like that, then it's probably wrong. (Henry Ford)
  Reply With Quote
Old 9th December 2010, 03:56 PM   #5
Mashoni is offline Mashoni  Germany
diyAudio Member
 
Join Date: Oct 2010
Send a message via MSN to Mashoni
if you plan on building the Bridge version of the TDA7294 please change the following values from the original data sheet from ST.COM for the :

Bootstrap cap from 22uf to 220uf - better LOW frequency response.
Input cap from 470nF to 4.7uF electrolytic or polyester cap.if you choose electrolytic remember to make sure the +ve pole of the cap faces the input and the -ve pole to pin 3 of the chip.

happy DIYing.
  Reply With Quote
Old 11th December 2010, 09:53 PM   #6
diyAudio Member
 
Join Date: May 2010
I have a 37 v , rectified can give 50v in about 10A (one bridge of 35a 400v and 4x 10000uf capacitors). Can i use it with a tda7293 using this board? if not, what can i do to lower the voltage of this power supply ? Thanks.
  Reply With Quote
Old 14th December 2010, 10:03 AM   #7
diyAudio Member
 
Join Date: Dec 2010
I've found this schematic on eagle software database, is it more effiscient or sound better then the recomended datasheet ?
Click the image to open in full size.
I'm about mount a 5.1 system with this chip, for the bass speaker i'm think to bridge two chips to provide a big woofers, for the rest a simple chip should be perfect,
My question is simple: what is the best schematic for TDA7294? (Power-Distorsion-Quality)? And what do you think about this one?
  Reply With Quote
Old 17th December 2010, 07:16 AM   #8
diyAudio Member
 
Join Date: Dec 2010
Any one? Any idea?
  Reply With Quote
Old 17th December 2010, 09:32 AM   #9
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
I wonder what C5 = 4n7F is doing?

It has RF attenuation at the input.
It has DC blocking at the input.
It has a Thiele Network at the output.
It has two stage decoupling on the power pins.
It has mute and standby implemented.
Many of the boxes are ticked.

I'm not sure the switchable unbalanced/balanced is a useful facility.
__________________
regards Andrew T.

Last edited by AndrewT; 17th December 2010 at 09:36 AM.
  Reply With Quote
Old 20th December 2010, 12:07 PM   #10
Mashoni is offline Mashoni  Germany
diyAudio Member
 
Join Date: Oct 2010
Send a message via MSN to Mashoni
use the datasheet it works 120% all the time.
  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
tda 7293 and tda 7294 help sagarverma Chip Amps 85 22nd March 2013 08:15 PM
again in dylema...but to cut down the cost of the woofer amp.TDA 7294 or LM3886? rhythmdiy Chip Amps 9 1st November 2007 06:19 PM
Amp on TDA 7294 maris24 Chip Amps 4 17th November 2006 10:11 AM
TDA 7294 amp with horns problems Bubba Zanetti Chip Amps 1 30th December 2005 02:00 PM


New To Site? Need Help?

All times are GMT. The time now is 07:49 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