[gkinberg]

I intend to use the same amp for my front three channels in my eventual home theater set up. There seems to be a greater selection of five channel amps than three channel amps. So how does one determine if amp channels can be bridged and then, what is the process of bridging these channels? Obviously, I’m somewhat new to this stuff; maybe all multi-channel amps are bridgeable. Thanks for any helpful comments.

Garth

[FullRangeMan]

Hi,
Not all amps are bridgeable. Some can be bridgeable at output post terminals, others amps are not designed to be bridgeable.
I can asure you the Musical Fidelity Electra3 integrated from 90years is not bridgeable, as I well remember I hear a PUTZ noise on the speakers and lost a IRF output device.
The Owner Manual of the amp must inform you if the amp is bridgeable or you can ask by email this info to the manufacturer(this is a plain, basic info, not secret).
Good Luck, Gustavo

[FullRangeMan]

what is the process of bridging these channels? Obviously,

You can bridge a Stereo amp in series or parallel for one channel performance, but before better read the Owner Manual looking for what type of bridge the maker recommend.
Top pro-audio Stereo amps as Bryston can be bridgeable easily to mono use.
Gustavo

[FullRangeMan]

Another tip:   Some amps have a diagram near the output posts showing you how to connect it.

[gkinberg]

Fullrangeman,

Thanks a lot for your input. I guess I have more research to do on my short list of amps.

Garth

[srb]

When you bridge a stereo amp to mono, the ouputs see half the load impedance.  So an 8 ohm speaker will look like a 4 ohm load, and a 4 ohm speaker will look like a 2 ohm load.
 
Therefore bridging an amp for a 4 ohm speaker load is not generally recommended.
 
Steve

[Elizabeth]

Bridging is a stopgap idea. If all you have is the amp in  front of you, and you want one BIG channel instead of two small,and the impedance is OK, and the amo can be bridged. Then bridge.
I would never PLAN on buying amps to bridge them. Buy the ones that work straight up.
bridging really does create greater strain on the amp. And more can go wrong, as it is stressed more.
Inexperienced folks want to "DO" special things (for cool factor, or just to be bigger, more,?) and do not realize it is harder to do them. Forget bridging, forget biamping. you will all be happier, and your stuff will be LESS likely to blow up.. (i am writing for all folks wanting to buy and bridge, not just the person who started this thread)
Since you do not currently own the amps.. I suggest you avoid doing bridging.

[gkinberg]

Thanks all, didn't know about the increased impedance issue of bridging. As mentioned above, want to amp my front 3 channels (LCR). Would like 200-250 wats/channel. My budget is $1000 max. I am considering buying used rather than new to increase value/cost ratio. There are fewer good used 3 channel amps than 5 channel amps that meet my criteria. Hence my bridging question, certainly not to be cool or have the biggest monoblock on the block 

garth

[Elizabeth]

You can just buy a five channel amp and leave two connected to some real small junk speakers with NO input. They would put a load on the amp. but use very little power, and make no noise. Then the amp would have more power anyway for the three used channels, AND your amp would have five channels when you want them.
The one small downside is it will use a little more power with two idle channels over a three channel amp.

[srb]

Although some amplifiers may require a load on their outputs, the solid state multi-channel amps I have owned did not. 
 
Another possibility is to passively bi-amp if your speakers have two pairs of bi-wire posts.  Passive bi-amping is not something I usually recommend, particularly if one is purchasing extra amplification to do so, as the results can often be marginal.
 
But if extra amplifier channels are sitting unused anyway, it would be something I would try (again, if the speakers permit it).
 
Steve