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My receiver says on the back that I should have 12-16 ohms impedence per speaker, if using both sets of speakers are turned on. Connected, I have one 4 ohm speaker [center, A] and a pair of 8 ohm rear [mono surroud, B]. It seems to work fine, none the less. Is there any 'danger' in doing this ? I am not even sure where I could find 16 ohm speakers.
 

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What make and model amp is this?


Does it have an output transformer?


16 ohm speakers were used many years ago. They were very useful when using long cable runs as you need much smaller cable to carry same amount of power as 8 ohm speakers.


All this became moot when the switch to transformer-less solid state amps occurred, because as a constant voltage source, solid state amps produce more power as the impedance goes lower (within limits). It was then that 16 ohms became impractical and most speaker manufacturers standardized on 8 ohms. Now-a-days you see a trend toward 4 ohms.
 

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I read that FAQ and I have a question. If a 4 Ohm speaker is harder to drive than an 8 Ohm speaker why do most amps say they are ... say... 125 watts per channel into 8 Ohms and 250 into 4?
 

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Quote:
Originally posted by FYTON2V
I read that FAQ and I have a question. If a 4 Ohm speaker is harder to drive than an 8 Ohm speaker why do most amps say they are ... say... 125 watts per channel into 8 Ohms and 250 into 4?
With the impedence halved, the speaker draws (or tries to..) twice the power from the amplifier. Some amplifiers are not capable of doubling their power output or increasing it much at all therefore only having 8/16 ohm ratings....Most amps do not "double" power into 4 ohms either. Some do 1.5 X the 8 ohm rating, others may only do 1.2 X, etc, etc...For example, my Bryston 4B does 250 watts into 8 and 400 watts into 4 ohms, a factor of 1.6....anyone else want to add?
 

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Also, some sneaky manufactures rate show there 4ohm rating, even though the don;t suggest you run the amp at 4ohms. It loks like the ampputs out allot of power, but what they don't tell you is that it will put out that power for only 4 seconds before the amp goes into protection.


What your amp is stating is, if you are going to use both A+B speaker outputs at the same time use speakers rated a 12-16ohms.
 
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