5 Channel Amps and Ohm Ratings?

[MPDano 10+ year member]

I am new to the 5 Channel Amps and was wondering if you could change the Ohm rating on the Front/Rear and Sub? Example: Front/Rear run at 4 Ohms and the Subwoofer runs at 2 Ohms.

Is this what 5 Channel Amps can do?

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[gunz4me2 10+ year member]

As long as the 5 channel amplifier is stable to all the impedances you are looking to run each individual channel at, it doesn't matter. For example, I am running my current four channel amplifier at 6 ohms on the front 2 channels and 4 ohms on the rear 2 channels.

I also ran a 25 to Life Power 1000 at 2 ohms on the front/rear channels and 1 ohm on the sub channel.

 

[MPDano 10+ year member]

Great info. Does the Amp adjust on it's own or is there usually a switch of sorts on the amp itself?

 

[gunz4me2 10+ year member]

Unless it is an ancient amp, it should handle the impedance differences on its own. The only multi-channel amp that I can think of that may have had switches to adjust the power supply for low impedance would have been the old Soundstream amplifiers made in the 90s.

 

[MPDano 10+ year member]

Excellent. I'll post up what I have in mind and see if you can tell me if it's ok. Much appreciate your info.

 

[MPDano 10+ year member]

How about this one? Current enough? I got my eye on a Memphis Belle too

Precision-Power DCX-800.5 PPI 800 Watt 5 Channel DCX Series Amplifier (PPI DCX800.5)

 

[smgreen20 10+ year member]

Both of those amps should be fine. To elaborate: if an amp is stable to 2 ohms on chs 1-4 and 1 ohms on ch 5, as long as you don't go below those rating (per ch) you'll be fine.

I run an Audison LRx5.1K, rated at 4 ohms chs A/B (chs 1and 2), 2 ohms chs C/D (chs 3 and 4) and 2 ohms on the sub ch (ch 5). I run mine at chs A-D at 4 ohms and ch 5 at 2 ohms.

 

[smgreen20 10+ year member]

??? triple post

 

[smgreen20 10+ year member]

??? triple post

 

[jeffsanders 10+ year member]

all amps are different, but in most, the front / rear are rated at 4 ohms, usually if they are stable at 2 ohms, the watts listed at 4 ohms generally doubles, so if you have 4 x 100 at 4 ohms, and you hook up a 2 ohm speaker to each, it will be 4 x 200 at 2 ohms, if you hooked up a 8 ohm speaker, it will generally reduce the watts by half (4 x 50 at 8 ohms) basically the same with the sub channel but some are stable at 1 ohm so if your sub channel is 1 X 200 at 4 ohms (1 x 400 at 2 ohms or 1 x 800 at 1 ohms or even 1 x 100 at 8 ohms.

 

[smgreen20 10+ year member]

By ohms law/in theory it should be as jeffsanders stated, but except for a few select amps, that is rarely true even if the company states those numbers.