Jump to content
SAU Community

Recommended Posts

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!

Link to comment
https://www.sau.com.au/forums/topic/6215-bridged-amp/
Share on other sites

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.

Link to comment
https://www.sau.com.au/forums/topic/6215-bridged-amp/#findComment-93274
Share on other sites

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

Link to comment
https://www.sau.com.au/forums/topic/6215-bridged-amp/#findComment-93791
Share on other sites

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!!

Link to comment
https://www.sau.com.au/forums/topic/6215-bridged-amp/#findComment-94657
Share on other sites

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 ;-)

Link to comment
https://www.sau.com.au/forums/topic/6215-bridged-amp/#findComment-94715
Share on other sites

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:

Link to comment
https://www.sau.com.au/forums/topic/6215-bridged-amp/#findComment-94817
Share on other sites

  • 3 weeks later...

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,

Link to comment
https://www.sau.com.au/forums/topic/6215-bridged-amp/#findComment-103637
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • It is a kunfine Android screen . Does anyone know the wirering diagram of the fuga ??
    • just an update to this, poor man pays twice  Tried sanding down the pulleys but it didnt do the trick. Chucked another second hand alternator in the na car which I got for free off my mate and its fixed the squelling. Must have been unlucky with the bearings.    As for my turbo car, I managed to pick up a cwc rb alternator conversion bracket + LS alternator for 250 off marketplace, looked to be in really good nick. Installed it , started the car and its not charging the battery.... ( Im not good with auto elec stuff so im not sure if this was all I needed to do but I verified such by using a multimeter on the battery when the engine was running and I was only getting 12.2v )   I had to modify the earth strap for the new LS alternator , factory earth strap was a 10mm bolt which did not fit the bolt on the LS alternator which was double the size so I cut it off , went to repco bought some ring terminals that fit, crimped it onto the old earth strap and bolted it up to the alternator , started the car and same issue. Ran like shit and was reading 12.2 at the battery.  For a "plug and play" advertised kit thats not very plug and play but alas.  My question is , am I missing something ? Ive been reading that some people recommend upgrading the stock 80 amp alternator fuse to a 140 amp but I dont see how that would stop the alternator charging especially at idle not under load.  Regardless ive pulled it out and am going to get it bench tested by an auto elec tomorrow but it would be handy to know if ive missed something silly or have done something wrong.   
    • My wild guess is that you have popped off an intake pipe....check all of the hoses between the turbo and the throttle for splits or loose clamps.
    • Awesome, thanks for sharing!
    • To provide more specific help, more information is needed. What Android screen? What is its wiring diagram? Does the car's wiring have power at any required BAT and ACC wires, and is the loom's earth good?
×
×
  • Create New...