bridging question

[bdavies11 10+ year member]

Im going to get this 4 ch amp... http://www.millionbuy.com/prfap1040.html

It does 75w x4 @4ohm but it says the rms is 225w x2 @ 4ohms bridged. I thought bridging would double the power. I figured it might be a misprint since the power trippled, so i checked Profiles website and it is not a misprint. In this case, how/why does the power tripple when bridging?

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[squeak9798 5,000+ posts]

When you bridge two amplifier channels, each channel will effectively "see" half of the load. Thus, a 4ohm load bridged to a pair of channels will result in each channel effectively "seeing" a 2ohm load.

So, bridging a 4ohm load across 2 channels should result in a power output of approximately the total of two channel's power output into a 2ohm load (since each channel will effectively "see" a 2ohm load, and hence output it's 2ohm rated power).

Or, approximately 4 times that of an individual channel into a 4ohm load.

 

[bdavies11 10+ year member]

thx