Power amps and Ohms.

P

ProJect

New member
Alright,

I am working on a bass rig. I have a Henry the 8x8 Cab and I wanna get a nice poweramp to power it. Now... everything I see says minimum load is 4ohms. I'm pretty damn sure my cab is 2 ohms. Yeah... it's 2 ohms. Can I use the power amp with my cab or will something 'splode? Also... if I bridge it at 8 ohms, what will happen when I plug that into my cab? I'm in over my head, but I just want a nice setup! HELP!

Proj
 
Many stereo power amps can run a 2 ohm load in "bridged" mode which basically converts the amp to mono. Most amps do this by engaging a bridge mode switch, and wiring across the channels.

If your amp is not capable of this you have two options:

Get an amp that can do 2 ohms

Rewire your cab internally to present a higher load to the amp.

I would not run a 4 ohm amp into 2 ohms. 2 ohms is damn near a dead short, and will likely fry the amp.
 
How do you know the cab is 2 ohms when everything you see on it says it's 4?
a 2 ohm load is really hard for the amp to drive, and can cause it to heat up faster, even if it is rated for 2. also, sound quality can suffer, generally the higher the inpedance, the better it will sound. ( up to about 8 ohms)

Actually very few power amps will bridge to 2 ohms, many will only go to 8, or maybe 4.
 
Crest amps handle 2 ohms with not sweet. You will be safe with on of the Crest CPX amps. If you have to two 4ohm speaker running of off the same amp than the load on the amp is 2ohms. I'm a Crest dealer so if you want a price email prosound@bellsouth.net I can save you some money
 
You might want to rewire the cabinet so it's a 4 ohm cabinet... it sounds like you might have a bunch of like 16 ohm speakers running in parallel or series parallel... it's not too tough to rewire a cabinet to gain a different input impedance.

Best of luck.
 
The Henry the 8x8 cabinet is 4 ohms.

A lot of modern amps can easily handle a 2 ohm load in stereo with no problems. I use a QSC PLX 3402 to drive 2ohm loads on subs all night long.

The Crest CPX can indeed handle two ohm loads. 2 ohms per channel in stereo. But not in bridge. 4 ohms only. Running below recommended impedance on a bridged amp will get you an expensive doorstop.

Any good power amp that can handle 4 ohms in bridge mono and gives you enough juice will do the trick.

If you need to add cabs later some amps have a switch for parallel mono. The amp stays in stereo but the mono input is split and sent to both channels. This allows you to take full advantage of the amp's power, use multiple cabs, and run low impedance loads.
 
M.Brane said:
Many stereo power amps can run a 2 ohm load in "bridged" mode which basically converts the amp to mono. Most amps do this by engaging a bridge mode switch, and wiring across the channels.
Click to expand...
au contraire ....... when you bridge an amp the minimum impedence goes up not down. So if an amp can handle 4 ohms per channel in stereo it goes to 8 ohms in bridged mode.
Parrallel mono is a different form of bridging and in that case the impedence does go down ........ but not regular bridging. And I'm not sure how many amps have the parrallel mono feature. I have a Crown that can be set up either way ....... bridged (8 ohm minimum ) and parrallel mono 9 2 ohm minimum )

Having said that ....... there are plenty of amps nowadays that'll handle 2 ohms ( such as my Crown in parrallel mono mode )
.
 
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