What will happen to my AV amp...

[Music4Life]

..it is setup to drive 8 ohms speakers, but my Centre speaker is only 4 ohms? Will it hurt my amp? The centre speaker? I don't want to change the setting on my AV to 4 ohms because my Front and Surrounds are 8 ohms. Any comment?

[mike c]

whats your av amp? for yamaha receivers, it was recommended by many that even when using 4 ohm speakers is to set to 8ohms

[Arneson]

You may want some extra cooling.
Heat is the enemy when your volume goes up.

[Ovation]

If you set your receiver to drive 4 ohms, it should still have no issues with your 8 ohm speakers, unless I'm much mistaken. The reverse, however, could lead to heating issues (or worse, if there are many 4 ohm and few 8 ohm speakers connected to the receiver).

[PewterTA]

I was always told to set it to the lowest ohm of your speakers... The amp will compensate for the difference in the 8-ohm vs 4-ohm.

[bleeding ears]

Setting the receiver to 4 ohm mode may be the safest way to do it, however from what i have been told the 4 ohm mode merely regulates the output of the receiver to make sure the amps inside dont self destruct. (due to high current and heat)

The downside is, because the receiver is being regulated it doesnt produce power in the same way and the sound suffers, and this is what I found with my setup using 4 ohm mode.

It may still sound alright in 4 Ohm mode, but it will probably sound better in 8 ohm mode.

If you play things at moderate volume levels you should be able to get away with 8 ohm mode, if you play stuff loud you are taking a risk with your receiver.

As was said above, it is all about heat. Stop it from getting too hot and it should survive the 8 ohm mode.

Warranty may not cover it if you fry it !

[Ovation]

Some 4 ohm settings do affect power as you describe on receivers, but not always (Arcam, for example, have such a switch but it does not have a deleterious effect on the power output). It would help to know the brand/model of the OP's receiver.

[mike c]

yamaha however cuts power by 50% (IIRC) in the 4 ohm mode.

put PC fans on top of your receiver and you'd be fine. you'd be surprised how much heat a single PC fan can save your receiver (I have two over the length of the heatsink). I would splice a 12v adapter plug to the PC fan, plug it into the receiver's switched outlet, and voila, a 12v triggered fan. make sure to pull out heat, not blow air in.

[Music4Life]

My AV is yamaha 659. My amp runs hot. I think I need to put some fan on it.

[gimpy]

I have the Yamaha 630. It is 4 or 5 yrs old and has been driving two 4 ohm main speakers now for a couple of yrs. Also, the center channel (Triune) is rated at 4 (maybe 6) ohms. I have had no problem with it (that I am aware of). I have the switch on the back set to "4" ohms. Watching dvd movies, I consistently run the power at the mid to high 30's which, I think, would put the volume power just a little over half way (zero being the most power and, again, I think, about 80 being mute).

Just recently (3-4 months ago), I bought a "pro amp" (Behringer A500) and use it to power the mains, connected to the avr's preouts. Something like this might be an option to power your center channel? My amp (Yamaha avr) runs "sort of" hot, I guess, but not so hot that it hurt/burns my hand. It is pretty well ventilated. Well, I just checked (wife is watching a tv movie, pretty low volume) and the avr is barely warm.

Frank