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bridged amp

predator

By predator,
in Car Audio & Electrical

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predator Grand Master

predator

Posted
Posted

I have an amp in my current car that i want to use in my next car. It's like a 75RMSx2 channel Sony job (before the x-plode range), not a bad little unit, still works pretty well.

Now a while back I remember I remember it could operate in "bridge" mode as well as the standard setting. Its been about 4 years since I bought it, and the instructions have long since been turfed...but i was just wondering what that means? From what I recall, it was something like I could wire it up so that instead of just running two speakers, I could run the one (or say a subby) at 150watt.

Is this correct? Anybody know what an amp that is "bridgeable" means???

If that is the case that is sweet, buy another new one that can do similar and either run a subby just off the one amp, or run one amp for one speaker and one for the other (me think I need powerful speakers then ~around 350Watt Peak). music power!

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SLY33 Mentor

SLY33

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Posted

hi dude, this topic took me a while to get my head around when i first started playing with amps, but now wreak my knowledge!!!

When you bridge an amp, each half of the amp sees "half" the load. So if you bridge a 4ohm sub over your 2 channels ( + terminal of one channel and the - terminal of the other channel) your amp will see a total load of 2 ohms. This is why you get doubled power output, as the resistance is less.

This is ample power to run any half decent 12inch sub.

But dude, your not going to use one amp per speaker for your front stage or rear fill! That is crazy, as you need no where near that amount of juice to get your mids and tweets cranking!! It is your sub that requires the power and is why people bridge amps to run them. -if you had a decent set of 6x9's or whateva connected to your sony amp in normal stereo mode (75w per channel is HEAPS of grunt) you would be sure to feel pain in your ears if you turned up the volume.

Consider a decent modern high-po deck, say 50 watts MAX. This deck has about only 22Watts RMS, and these will still crank hard enough for most people. So 75 per channel is loads!

Also your amp may be bridgeable, but you still need to know at what load it is STABLE at. eg it may be bridgeable but not 1ohm stable like RATTUS's amp, in which case if you load it like that you could smoke your amp.

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predator Grand Master

predator

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Thanks, I am a little more filled in now on what i need to know...

But dude, your not going to use one amp per speaker for your front stage or rear fill! That is crazy, as you need no where near that amount of juice to get your mids and tweets cranking!! It is your sub that requires the power and is why people bridge amps to run them. -if you had a decent set of 6x9's or whateva connected to your sony amp in normal stereo mode (75w per channel is HEAPS of grunt) you would be sure to feel pain in your ears if you turned up the volume.  

Consider a decent modern high-po deck, say 50 watts MAX. This deck has about only 22Watts RMS, and these will still crank hard enough for most people. So 75 per channel is loads!

hehe... not always ! I have a 5 year or so old Pioneer deck that puts out 25W RMSx2 as standard - that wasn't always enough when crusing down the freeway with the windows down and that is why I bought the amp - there was a lot of noise loss at that speed and therefore wouldn't go loud enough. When camping as well, its good to have a stereo on wheels - as long as the amp doesn't draw too much power you can get a good 5 hours cd's before the battery drains.

Yup, 75W is loud, however it did distort when you cranked it right up - but that was generally due to my supposedly 200watt (peak) speakers that weren't really able to handle up to that. Generally that was of course much much louder than you could handle just driving around in traffic all day.

Over the 4 years or so, my 16x9's put a bit of a crackling now - prolly too much volume for too long + sun damage from parcel shelf. Anyway, all of that stuff is going in my old car because its pretty outdated... I'm just keeping the amp

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riggaP Veteran

riggaP

Posted
Posted
Originally posted by predator666

Yup, 75W is loud, however it did distort when you cranked it right up - but that was generally due to my supposedly 200watt (peak) speakers that weren't really able to handle up to that. Generally that was of course much much louder than you could handle just driving around in traffic all day.

Over the 4 years or so, my 16x9's put a bit of a crackling now - prolly too much volume for too long + sun damage from parcel shelf. Anyway, all of that stuff is going in my old car because its pretty outdated... I'm just keeping the amp

When looking at stereo equipment, never, never, EVER, judge it by its music/PMPO/peak power ratings. These ratings often mean nothing, it could mean the point at which the voice coil melts! A 200W peak power rated speaker could prolly only handle about 20W RMS. Thats why when you put 75W RMS in to a 200W peak/music rated speaker they distort. 75 RMS is prolly closer to 1000W peak!!

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predator Grand Master

predator

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Yup, I'm aware of RMS and Peak figures and how you read anything that reads 400watt it ain't 400watt. I read up a bit a few years ago when i bought the stuff, but of course I forget many things!

The 16x9's were Sony you see at 200W and matched fairly well with the amp - so I trusted those figures a lot more than others at the time (going on previous Sony equipment). They were/are good speakers but any speaker over time starts to deteriorate.

Why amps are in RMS and speakers still all in peak I don't know. The foruma I believe is Peak = (RMS * root2) *2 and then some - So 75W peak can drive 220watt or so peak speaker. Correct me if I am wrong.

Of course many don't know that, or actually believe those big numbers! If they were really 200W speakers we'd all be running them in our house, not the car ;-)

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riggaP Veteran

riggaP

Posted
Posted
Originally posted by predator666

Of course many don't know that, or actually believe those big numbers! If they were really 200W speakers we'd all be running them in our house, not the car ;-)

And our ears would be bleeding! hmmm 200W RMS speakers... I spose they'd go as hard as a car with 200rwkws! NICE!:cool:

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  • 3 weeks later...
NO_RSPECT Mentor

NO_RSPECT

Posted
Posted

Hey guys, do you know anyone selling an amp rated at roughly 300rms upwards into 1 channel. secondhand, I only have like $300 - $380 bucks. yeah tough ask i know but of anyone is selling something decent let me know. I forked out too much for a Square kicker solo baric and it needs JOOCE

thanks, sorry to hijack,

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