Would you use a 4780 in a parallel or bridged configuration with 6 ohm speakers? - 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 14th February 2010, 03:17 AM   #1
GregH2 is offline GregH2  Australia
diyAudio Member
 
GregH2's Avatar
 
Join Date: Oct 2009
Default Would you use a 4780 in a parallel or bridged configuration with 6 ohm speakers?

Title says it all. My transformer choice is +/-22v.

Interested to know your thoughts, as this seems to be an intermediate speaker impedance and it is difficult to know which way to go. I'm thinking parallel would be best...

Thanks,

Greg.
  Reply With Quote
Old 14th February 2010, 05:33 AM   #2
sangram is offline sangram  India
diyAudio Member
 
Join Date: Sep 2002
Location: India
Single 4780 channel is not 3 ohm capable, hence parallel is the only way out.
  Reply With Quote
Old 14th February 2010, 08:18 AM   #3
GregH2 is offline GregH2  Australia
diyAudio Member
 
GregH2's Avatar
 
Join Date: Oct 2009
Quote:
Originally Posted by sangram View Post
Single 4780 channel is not 3 ohm capable, hence parallel is the only way out.
Hi Sangram,

Thanks for your reply, however I am confused. What does 3 ohms have to do with anything when my speakers are 6? Could you please explain?

Thanks,

Greg.
  Reply With Quote
Old 14th February 2010, 08:25 AM   #4
Nisbeth is online now Nisbeth  Denmark
diyAudio Member
 
Nisbeth's Avatar
 
Join Date: Jan 2001
Location: Denmark
If you bridge an amplifier, each amplifier channel will see half of the load impedance, meaning 3 ohms here.

/U.
  Reply With Quote
Old 14th February 2010, 08:31 AM   #5
GregH2 is offline GregH2  Australia
diyAudio Member
 
GregH2's Avatar
 
Join Date: Oct 2009
Quote:
Originally Posted by Nisbeth View Post
If you bridge an amplifier, each amplifier channel will see half of the load impedance, meaning 3 ohms here.

/U.
OK, fantastic thanks. Parallel operation it will be then.

Greg.
  Reply With Quote
Old 15th February 2010, 02:04 PM   #6
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
I would be tempted to say the two channels inside a 4780 are not 4ohm speaker capable, but that many use them into this more demanding load and find the results good enough.
6r0 could demand upto 5Apk. A parallel 4780 can output upto 14Apk to a load. A pair of 4780 channels fed from 22+22Vac should have sufficient current capability to drive a reactive 6ohm speaker load without triggering Spike or any other limiting if you can keep the chip cool. There is your problem.
__________________
regards Andrew T.

Last edited by AndrewT; 15th February 2010 at 02:08 PM.
  Reply With Quote
Old 16th February 2010, 12:33 PM   #7
diyAudio Member
 
kuldeepsingh's Avatar
 
Join Date: Aug 2006
Location: Chennai, India
Send a message via MSN to kuldeepsingh
Still parallel operation is more viable solution for 6 ohm @ normal listening levels, provided u don't use speakers at full volume.
__________________
. . .. ... ..... ........ ............. ..................... ..................................
My Blog
  Reply With Quote
Old 13th May 2010, 12:01 PM   #8
Banned
 
Join Date: Apr 2010
If I get the PD 4870 kit and wish to run parallel monoblocks all I need to do is add the extra parts to the pcb and get two tranies correct? And that will put me at about 100w per channel at 8 Ohm?
  Reply With Quote
Old 13th May 2010, 12:36 PM   #9
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
Parallel will still produce up 60W into 8ohm, to get more power you need to use 4 ohm speakers.

Two tranies are required for dual mono, more info on the kit here: Kit arrived
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
  Reply With Quote
Old 13th May 2010, 01:49 PM   #10
diyAudio Member
 
Join Date: Feb 2008
Location: Jackson,michigan
You must also keep in mind that an amplifier output voltage swing is determined by the power supply's RMS voltage minus 2.5v to 3.5v (see data sheet) because it can't swing compleatly to the rail and not the peak voltage as measured at the filter capacitor.
therefore with a 22v transformer it can only produce less than 80 watts into a 6 ohm load.
At least a 26v-0-26v transformer should be considered and a 28v-0-28v would be optimum to get a full undistorted 100watts into 6ohms.
I have seen this question time and time again and this has never been mentioned or discussed.
Yes,a higher power supply voltage means warmer chip temps,just use an adequate heatsink and you shouldn't have any problems. jer
  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
Bridged 4780 for 4ohms load? jaste Chip Amps 18 26th May 2010 04:46 PM
4780 stereo, parallel, bridged, single sided gmphadte Chip Amps 12 12th March 2007 11:42 AM
Bridged 4780 with 35V rails akunec Chip Amps 0 20th October 2004 12:25 AM
4780 Bridged PCB designs? Nappylady Chip Amps 0 28th April 2004 05:25 PM
Two 4 ohm woofers in series or two 16 ohm in parallel. Which is better? Cal Weldon Multi-Way 16 21st February 2004 12:31 AM


New To Site? Need Help?

All times are GMT. The time now is 04:45 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