Matching amp head and cabinet wattage...how close is close enough?

Bassguy1 · #1 10-15-2010, 06:57 AM

With all of the more powerful amp heads available now I imagine some damage would result to a cab if the amp head is running more watts then the cab is rated...but how much more? For example if a single 4ohm cabinet is rated 500 watts and the head is rated 500 watts at 4 ohms then I guess I'll be ok. But I'm considering the new GB 9.0 at 900 watts with a single 4 ohm cabinet rated at only 500 watts. Am I looking for trouble or is it time to get a new cab also rated closer in wattage to the head? I only want to lug around a single 4ohm cab.

dmusic148 · #2 10-15-2010, 07:02 AM

The 500 watt rating for the cab is, unfortunately, not very useful. It's the thermal rating, which doesn't help much in the real world of musical signals. You really just have to use your ears to know if the cab is getting into trouble. It will let you know.

philtoler · #3 10-15-2010, 01:22 PM

If it's a 100% solid state amp you should be fine so long as you avoid "clipping" - when the little pre amp light (if you have one) blinks a lot and you are pumping high main volume output, you are in dangerous territory. In fact a 100W solid state amp clipping heavily could damage a much higher rated cab because of the badly distorted wave forms. Not so much of an issue for a valve amp because the wave forms are less "nasty" to a speaker.

Munjibunga · #4 10-15-2010, 01:27 PM

I run 750- to 1,100-watt heads into 500-watt cabinets all the time. You have to be judicious in your application of the power available. At sound of first fart, turn it down.

billfitzmaurice · #5 10-15-2010, 01:38 PM

Quote:

Originally Posted by philtoler

In fact a 100W solid state amp clipping heavily could damage a much higher rated cab because of the badly distorted wave forms. Not so much of an issue for a valve amp because the wave forms are less "nasty" to a speaker.

Alert the mods, another myth of under-powering thread to be shut down.