8x10 Questions

[LarkinLondon]

I have an amp head that can either do 400 watts into 4 ohms [stereo] or 800 Watts into 8 Ohms [bridged].

My cab is an 8x10 4 ohm cabinet. I generally play at lower volumes and I wondered which was the best way to run my amp into my cab?

I lug my 8x10 around to a lot of venues of all sizes and wondered if there was any merit to getting a 4x10 cab for the smaller venues? If so, what ohm cab should I be looking for?

 

[LiquidMidnight]

Don't bridge the amp into a 4-ohm load if it can only handle an 8-ohm load.

 

[LarkinLondon]

Don't bridge the amp into a 4-ohm load if it can only handle an 8-ohm load.

The cab is 4 ohm, so shouldn't it be able to handle 4ohm and 8ohm?

 

[Downunderwonder]

You can't bridge it. So you have to run with one channel. If 400w into 4ohm 8x10 isn't loud enough you're very loud.

But since you think a down sizing is in order, you should get a pair of 2x10 to stack vertically. All the monitoring you get now instead of having it blasting below with 4x10.

 

[LiquidMidnight]

The cab is 4 ohm, so shouldn't it be able to handle 4ohm and 8ohm?

No, the cab's impedance is fixed (though it probably isn't 4-ohms flat throughout the entire spectrum, but for practical purposes, it's always 4-ohms). Modern Ampeg 810e cabs have stereo capability, and I believe each 4x10 can be run as an 8-ohm cabinet; however, when all speakers are operated in mono, it's a 4-ohm cabinet.

The cabinet's impedance rating cannot be lower than the head's minimum load rating. In this case, if the amp's minimum load is 8-ohms, it would most likely damage it to be played into a 4-ohm load for any significant amount of time. While you should always consult a manual, as a general rule of thumb, if each power section in a stereo amp cannot handle a 2-ohm load, it is probably not able to handle an 4-ohm load in bridge mode.

 

[LarkinLondon]

No, the cab's impedance is fixed (though it probably isn't 4-ohms flat throughout the entire spectrum, but for practical purposes, it's always 4-ohms). Modern Ampeg 810e cabs have stereo capability, and I believe each 4x10 can be run as an 8-ohm cabinet; however, when all speakers are operated in mono, it's a 4-ohm cabinet.

The cabinet's impedance rating cannot be lower than the head's minimum load rating. In this case, if the amp's minimum load is 8-ohms, it would most likely damage it to be played into a 4-ohm load for any significant amount of time. While you should always consult a manual, as a general rule of thumb, if each power section in a stereo amp cannot handle a 2-ohm load, it is probably not able to handle an 4-ohm load in bridge mode.

Okay, so I should only bridge my amp head if I have an 8ohm cab.
So the best set up right now is to just have one 4 ohm channel running into my 8x10?
And if I decided to get 2 2x10s I would run a left channel into one and a right into the other.

 

[LiquidMidnight]

Okay, so I should only bridge my amp head if I have an 8ohm cab.
So the best set up right now is to just have one 4 ohm channel running into my 8x10?
And if I decided to get 2 2x10s I would run a left channel into one and a right into the other.

Yep, you got it.

There are amps out there that are bridgeable into 4-ohm loads, but it sounds like yours isn't designed for it.