# oh my Ohms are tired

Discussion in 'Amps and Cabs [BG]' started by muddpuddle, Dec 22, 2013.

1. ### muddpuddle

Mar 5, 2012
Can anybody help me understand amps and ohms

I have an old peavy head that's rated 210 amps at 2 ohms. What would be the result of playing through a single 8 ohm speaker

2. ### B-stringSupporting Member

I'm sure you meant 210 WATTS not amps. Being a SS amp, use of an 8 ohm speaker would just mean it will produce much less wattage from the amp.

The "Stickies" are chocked full of ohms/wattage info.

3. ### beans-on-toastSupporting Member

Aug 7, 2008
Oh my is right! That would be 88,200 watts. I figure that you'd probably blow your speaker.

First step in answering your question is to know what model amp you have.

4. ### swamp_bassI love it when a groove comes togetherSupporting Member

Nov 20, 2013
North Cackalacky
The general rule is that an amp's output will be half at double the speaker impedance. Many amps aren't quite linear that way, but it's a good general way to approximate.

So 210 Watts into 2 ohms becomes:
* 105 Watts into 4 ohms,
* 60 Watts into 8 ohms.

Many amps deviate from that general rule. Often amps that are "stable to 2 ohms" use active current limiting at 2 ohms that limits power to approximately the same output as 4 ohms. If that's the case, then your output into 8 ohms would be more like 100 watts.

So somewhere between 50 and 100 is the ballpark.