Is is possible to bridge every amp - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 January 2004, 02:00 PM   #1
diyAudio Member
 
Join Date: Dec 2003
Location: Victoria Australia
Send a message via MSN to priscared
Default Is is possible to bridge every amp

Gday,
Is it possible to bridge any stereo amp simply by connecting your speakers to the positive termanils and haveing a mono opposite input?
Thankyou
Or does it have to be built for this operation.
Daniel Priscared@hotmail.com
  Reply With Quote
Old 18th January 2004, 03:05 PM   #2
Did it Himself
diyAudio Member
 
richie00boy's Avatar
 
Join Date: Nov 2003
Location: Gloucestershire, England, UK
It works with probably all conventional amps, just be aware that you must use double the rated minimum load impedance per channel.

I know for a fact that you can't do it with the Technics New Class-A and Class-AA amps as they use funny o/p circuitry/rail arrangements.
  Reply With Quote
Old 18th January 2004, 06:22 PM   #3
diyAudio Member
 
Join Date: Jan 2004
Location: Germany / Bavaria / Augsburg
Basically you can bridge any amps having an output signal referred to ground.

Amps, that already have a bridged design cannot be further bridged.
__________________
Best Regards,
Cybergent
  Reply With Quote
Old 18th January 2004, 07:20 PM   #4
diyAudio Member
 
Join Date: Apr 2002
Location: California
Most amps could be bridged, but many cannot. The main factor is if the grounds or black binding posts of each channel are common to each other and to the ground power supply.

Some amps have the equivelent of a balanced output and both positive and negeative posts swing agianst the other to create a potential that the speaker "floats" between. Classic case of Single Ended Output Vs Balanced Output.

My advice: If you are not sure, do not try. It could be an expensive and smokey mistake. Conventional wisdom says bridging will give you 2 times the power but that translates into only 3dB louder. is it worth it?

Aud_Mot
  Reply With Quote
Old 19th January 2004, 05:13 PM   #5
maylar is offline maylar  United States
diyAudio Member
 
Join Date: Jun 2003
Location: Connecticut
The amp outputs have to be referenced to a common point (typically ground), and one channel has to be inverted. The output voltage doubles but the current limit stays the same, so you need to double the rated load impedance to be safe.
__________________
dave
  Reply With Quote
Old 19th January 2004, 06:49 PM   #6
azira is offline azira  United States
diyAudio Member
 
Join Date: Dec 2003
Location: Near Seattle
Quote:
Originally posted by Cybergent
Basically you can bridge any amps having an output signal referred to ground.

Amps, that already have a bridged design cannot be further bridged.

Talking very theoretically and certainly not practically.... shouldn't you be able to parallel two bridged amps?
  Reply With Quote
Old 19th January 2004, 07:06 PM   #7
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
Quote:
Originally posted by Aud_Mot
Conventional wisdom says bridging will give you 2 times the power but that translates into only 3dB louder. is it worth it?

Aud_Mot
Erm..... not quite true.

If your standard amplifier is capable of doubling current
into half your loudspeakers impedance load its not.
(e.g. 60W into 8 ohm > 100W into 4 ohm)

P = Vsquared/R or IsquaredxR, either way its times 4 = 6dB.

(with the above example assuming current limiting = > +4.5dB)

But what is true is an amplifier that cannot drive low impedance
loads is not suitable for bridging, and that low impedance speakers
are not suitable as a load for bridged amplifiers.

I completely agree with the sentiment "is it worth it ?" nearly
allways its not as the speakers are not a good load for bridging.
(Unless we are talking about car audio etc)

sreten.
  Reply With Quote
Old 21st January 2004, 12:22 AM   #8
manxam is offline manxam  Canada
diyAudio Member
 
Join Date: Dec 2003
Location: Ontario
Assuming that all of the above were true about an amp (common ground and what-not), could someone please post a schematic describing this 'bridging' circuit.

I'd like to use a 4 ohm stereo stable 20 year old solid state Toshiba receiver for a sub amp.

Any help would be appreciated.

Thanks!
  Reply With Quote
Old 21st January 2004, 12:45 AM   #9
sam9 is offline sam9  United States
diyAudio Member
 
sam9's Avatar
 
Join Date: Jun 2002
Location: Left Coast
Using a bridged amp to drive a 4 ohm speaker is dodgey. The reson is that from the amp's point of view (pardon the anthromorphology) is will see not 4 ohms but 2. That's real low for many amps and smoke the output transistors or at least activate short circuit protection.

That's no to say you can't do it but a large number of amps (Most, perhaps) won't do well. That said I did this once with a Carver M-400 with no appearent harm, although thinking about it kept me kind of puckered up.
  Reply With Quote
Old 21st January 2004, 01:33 AM   #10
Account Disabled
 
Join Date: Apr 2003
Location: US
Default Re: Is is possible to bridge every amp

Quote:
Originally posted by priscared
Is it possible to bridge any stereo amp simply by connecting your speakers to the positive termanils and haveing a mono opposite input?
the answer is clearly no. as it is entirely possible to design an amp that is NOT bridgeable.
  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
Full Bridge X Half Bridge: What's The Best? CHACALPOWERS Power Supplies 8 18th July 2008 04:45 PM
Reopening an unfinished debate: Dual bridge vs. Single Bridge xiphmont Chip Amps 15 26th February 2008 07:22 PM
The difference of Push-pull,Half-bridge,Full-bridge digi01 Chip Amps 0 8th September 2006 02:10 AM
Whats the difference between full bridge and half-bridge SMPS ? skaara Class D 6 3rd February 2005 07:23 PM


New To Site? Need Help?

All times are GMT. The time now is 02:38 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