bridge 4 channel efficiency vs 2 channel

[Lil Poot 5,000+ posts]

ok so i'm not so satisfied running active with my 4x50 @ 4 ohm 4 channel. it sounds good, but isnt powerful enough to run my single voice coil 8 ohm sdx7's. they're wanting about 150w per side, which is hard to get a 8 ohms. i'd like to put about 100 watts on my tweets also.

so here are my options -

A. buy a big 4 channel, 150w per channel @ 4 ohms,

B. buy another 2 channel, probably a us acoustics USA2150, 2x150 @ 4 ohms to run my mids, keep the 4x50 bridged to my tweeters

C. buy a supplementary 4 channel. i have a chance to buy a nice 4x80 amp that does 240x2 @ ohms bridged.

now, when i bridge 2 of the channels to a single voice coil 8 ohm speaker, that still puts a 4 ohm load on the amp right, so i'll be seeing the 240x2 4 ohm rating from the amp?

how about efficiency? the 4 channels i've been looking at the zuki eleets, and the DD S4 use dual power supplies inside, would that make it draw as much current as 2 amps? how about 2 channel vs bridged 4 channel efficiency?

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[helotaxi 5,000+ posts]

Each channel will see a 4 ohm load so the bridged channel would be providing 2x the power of a single 4 ohm channel. In the case of the amp you're looking at it would be 2x160 @ 8 ohms bridged.

 

[thch 10+ year member]

"now, when i bridge 2 of the channels to a single voice coil 8 ohm speaker, that still puts a 4 ohm load on the amp right, so i'll be seeing the 240x2 4 ohm rating from the amp?"

nope, you're counting the effect twice. In a bridged configuration, each channel see's a load equal to half of the actual load impedance. in this case, each channel see's 4ohm. the total power output would be twice the rating of a single channel @ 4ohm, or whatever the amplifier is rated for @ 8ohm bridged. most likely, the amp won't list an 8ohm bridged rating, but will list the 4ohm per channel rating.

 

[Lil Poot 5,000+ posts]

any rough guess on what a 150x2 @ 4 ohm amp might do at 8 ohms?

 

[Horsemanwill 10+ year member]

75x2

 

[helotaxi 5,000+ posts]

any rough guess on what a 150x2 @ 4 ohm amp might do at 8 ohms?

Depends entirely on the amp.

 

[Lil Poot 5,000+ posts]

any amps that are known for good performance at 8 ohms?

 

[RAM_Designs 5,000+ posts]

Best bet for you would be to bridge the amp you already have and get 2x100 at 8ohms out of it for your mids...then just get a little 2x50 amp for your tweets.

 

[Lil Poot 5,000+ posts]

thinking of grabbing a usa2150 for the tweets, and bridging the 4050, amps would match that way and should have good power. cheap too //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[RAM_Designs 5,000+ posts]

^^^solid amps too, gotta love zed built stuff.

 

[Lil Poot 5,000+ posts]

picked up one of the skinny usa2200s, without the fan. going to run that to the mids, get roughly 100x2 @ 8 ohms and 12v, and bridge the 4050 to my tweets, about another 100x2 @ 4 ohms.