Amps, Speakers and Ohms....ZZZZZ

[Disco_Dave]

I'm looking at an amp to power monitor speakers. It says it produces 130 watts per channel into 4 ohms. I have some HiFi speakers as well and was wondering if I could also use it top power those, except on the box it says they are 8 ohms...can I still use these together? Will it blow up my flat? Will the world stop spinning?

All this technical talk is over my head...i'm a musician not an electrician! It's gotta be done though.

[Richard Monroe]

No, the world won't end, it'll just underpower the speakers, so your output will be limited, and you'll develop noise floor issues when the amp is cranked. I used to drive a 16 ohm Celestion GT30 with a 4 ohm Samson Servo 150, and it worked OK, up to about 12 watts of death defying power. I switched to an 8 ohm vintage 30, and got a power amp that's "bridgeable" so it can be 4 ohms 2 channel or 8 ohms mono, so it can drive either arrangement with a little re-patching. I don't use it to drive monitors, though, mine are powered. It does, however, work very well with a POD Pro guitar amp modeler. The nice clean amp doesn't mess too much with the amp models and distortions of the POD.-Richie

[Lt. Bob]

Yes it will work just fine.
I disagree with the comment that it will "underpower the speakers". There's not enough info to be able to say that. Because of the lack of information I'm gonna be speaking very generally here but if an amp puts out 130 watts into 4 ohms; it probably puts out somewhere in the range of 70 or 80 watts into 8 ohms. That's certainly enough to power any halfway efficient speaker. And depending on the listening purposes, you might not use that much. In near-field situations, and at reasonable volumes you commonly only use maybe 20-25 watts if that. The excess power is need for headroom on transient peaks.
Now if you want to listen at head-banger levels.....70 watts into 8 ohms might not be enough but otherwise I bet it'll do fine.
This is all based on the idea that it's a decent quality amp. What kind is it?

[Richard Monroe]

I stand corrected, Bob. I should have said that the speakers will deliver less than the amp's rated output. Depending on the capacity of the speakers, it might actually overdrive them.-Richie

[Disco_Dave]

thanks for explaining, a friend of mine told me the same thing but he is known for just bullshitting when he doesn't know the answer to a question so I thought i'd seek help from the experts!

The amp i'm looking at is a Samson Servo 170 or 260. I've heard that they are decent quality for the price. They are primarily being bought to power monitors but I was just wondering whether I could use them to power speakers as well...although it's very much a secondary concern...just being a cheapskate really i suppose!

[dragonworks]

Theres plenty of cheap power amps out there, check out Carvin.
50 cents a watt. You should be able to pick up something for about 25 cents a watt used.