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What's your oppinion on bridging two channel amps?

I've been reading on the web about bridging two channel amps and it seems that some people believe it isn't a benefit. I've noticed that most manufacturers say that you should only use an 8 ohm speaker when bridging, but don't most speakers dip below 8 ohms? It probably varies from amp to amp on the benefits, but I was looking into purchasing a rotel rb980bx to use for a center channel amp and it has the capability to be bridged but some people said the sound was worse, just louder. What do you think about bridging my classe ca-150 for center channel duties and using a b&k st125.2 for front right and left channels? Thanks guys!

P.S. one of these days I'll quit posting new threads all the time, it's just that I know you guys (and gals) are experts. I really appreciate all the help and knowledge I've obtained from everyone out there. I'd be so much further behind if it weren't for you. Thanks.
b_limo
elizabeth
6,726 posts
 
Well, only IF the manufacturer mentions the amp can be bridged. Then it MUST be done the way the manufacturer says to do it.
Generally bridged amps are poorer than the unbridged amp.
The impedance is part of it.
Most folks who want to bridge want more power.
Some want (like the op) to just be able to use it for a center channel.
If it was me, i would just connect up one side of the amp, and let the other side sit powered up, but unused.
pbnaudio's avatar
pbnaudio
1,534 posts
 
Bridging or differential mode got a back wrap way back when SS amps were in their infancy. If properly implemented in my experience it is a vastly superior way to operate an amplifier. All my amplifiers are designed so that they can be operated as either a Stereo amplifier or a Mono block. There are many advantages other than approximately four times more power gained like better S/N ratio as well as twice the speed.

So if your amplifier is set up to allow for this I strongly recommend it


As always good listening

Peter
ngjockey
1,042 posts
 
Depends on the amps and the load. I have bridged Plinius amps going into 4 ohms but the speakers are magnetic planar and not reactive. They also crossed over above 100 Hz. Those amps also worked well with dynamic speakers I built but those had an unusual (series-parallel) rising impedance below 500 Hz. Most mid-woofers have a minimum impedance around 200 Hz. Some worse than others and compounded in parallel.

Been shopping for a pro amp for a subwoofer project. The subs are 4 ohms (nominal) each and I want to be able to use one or both. Most pro amps can be bridged but they have to be rated for 2 ohms stereo to be bridged into 4 ohms and that eliminates most but the "heavyweights".
csontos
1,275 posts
 
I just had 3 Acoustat TNT200s rebuilt by Roy Esposito with added mono capability. Roy was part of the team that designed the amp so as Peter stated, implementation is key. These amps are excellent in stereo but better in bridged mono mode. Stable down to 4 ohms bridged. However, they were designed for low impedance loads in the first place so I would think likely candidates would be of similar capability.
dc2daylight
53 posts
 
In regards to your Classe, both my 300 and 400 sound better bridged. As far as speaker loads go, they work fine with my Thiel 7.2 and 3.5 .
You may find that your Classe runs hotter bridged, but that would be normal for Classe.
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