a newb question about amps

[norachelhere]

hey
i'm pretty new to the whole car audio thing. I've always been too worried about going fast to be concerned with audio. But now i've got a car that i want to do up to be nice, not to fast, just nice.
Anyway. I've been told that you can "overclock" amps to put out alot more power.
Is that true? If so, how does one go about doing so?
I've got an old 2 channel 75 watt amp that I'm not too concerned about it dieing. If it lasts, great, if not, thats fine too. It would just be nice to get some power to play with.
thanks for the help

[POST]

Never heard of overclocking an amp, but what you're probably talking about is putting it to a lower impedance or bridging it.

Make sure that the amp can handle what you're doing to it or it'll send itself into protection mode if it even has that.

[the727kid]

You can modify certain amps by removing a piece of the board. Usually they are Class Ds though, never heard it with a Class A/B.

[norachelhere]

I didn't know if there was stuff you could add/take away from the broad to modify its output. I've only heard about it. I've actually had someone hold this particular amp in their hands when they told me about this whole concept.
I understand you can bridge the outputs and you actually end up with more power than the two channels seperatly. Something like 3 to 4 times. (4 times in a perfect world) But these guys are talking about a whole lot more power than that. He said that 1,500watts out of this amp wouldn't be that hard to accomplish. i don't know if I'm not searching the right words or if this is just a bunch of talk from a bunch of punks, but i can't really find any info about it. Its been refferenced in a few tech articles. things like you shouldn't operate an amp outside of the manufacturer specs because you run the risk of damaging it.

[norachelhere]

is there a way to change the ohms on an amp?
I mean other than flip the switch. I had a buddy that had a much higher end set up and he said that he would run at 4 ohms every day and drop it down to 2 ohms at competition.
This amp doesn't have that switch, is there something that can be tweaked to accomplish the same thing?

[the727kid]

If you get 1500 watts out of a 75x2 amp I will hand you over my car.

[norachelhere]

yeah, it sounded kinda funny to me too.....

i would have been happy with a few hundred, 1,500 seemed outlandish to even me.

[POST]

is there a way to change the ohms on an amp?
I mean other than flip the switch. I had a buddy that had a much higher end set up and he said that he would run at 4 ohms every day and drop it down to 2 ohms at competition.
This amp doesn't have that switch, is there something that can be tweaked to accomplish the same thing?

Most amps i've seen don't have a switch, you just have to wire it a certain way (also dependent on the number of woofers + what their connector types are)

[norachelhere]

i have to assume it is a switch because he didn't have any tools, and it took like 2 seconds. He reached in, and did something (flipped a switch) and his ohms were different. No noticable re wireing.

[norachelhere]

maybe i'm just thinking to far into this whole thing.
Maybe a more simple approach to this rather interesting idea might be needed.....

[POST]

i didn't say it probably doesn't exist, i'm just saying you won't see most amps with them

[POST]

maybe i'm just thinking to far into this whole thing.
Maybe a more simple approach to this rather interesting idea might be needed.....

yeah buy a bigger amp.

I'm selling an 800wRMS (Its actually more but i haven't re-metered it to find out exactly what) old Boss amp (yes the brand sucks but the amp is actually decent) for about 80 bucks. That should be more than enough to power your subwoofer(s). Also comes with a remote level module.

[norachelhere]

when i get 80 bucks, i'll let you know. I was just looking for a project to play with until I get my financial ducks in a row.

thanks

[POST]

uhh, what subwoofer(s) do you have/own/planning on using.

[norachelhere]

uhh, what subwoofer(s) do you have/own/planning on using.

Right now, I've got a sony 150watt and an off brand 150 watt.
I wasn't planning on keeping these. I just thought it would be fun to play with for a bit. you know the whole learning by doing/messing it up.

I'm a fan of JL audio, I really like the sound of a JL system. but again, I don't know enough to look at a spec sheet and decide whats good.
I would rather have a "perfect" sound instead of being record setting loud..... Don't get me wrong I like loud, but sound quality is more important to me than sound quanity.

[Notladstyle]

addressing the original ? - you can open the amp up and modify the hardware to produce more output at a cost of heat and shorter life.

Usually there are a set of POTs or resistors that set the nominal voltage for the switches that can be changed. If you are bold enough to open it up, post a picture(high res) and I'll point them out to you.

[POST]

Right now, I've got a sony 150watt and an off brand 150 watt.
I wasn't planning on keeping these. I just thought it would be fun to play with for a bit. you know the whole learning by doing/messing it up.

I'm a fan of JL audio, I really like the sound of a JL system. but again, I don't know enough to look at a spec sheet and decide whats good.
I would rather have a "perfect" sound instead of being record setting loud..... Don't get me wrong I like loud, but sound quality is more important to me than sound quanity.

As karts will probably come in here in like 2 minutes and yell at you for saying the JL name... JL isnt the only thing that sounds "good"... It mainly depends on how you set it up. I have ALL different brands of audio, and me and a few folks will tell you, it sounds clean as hell compared to a lot of systems.

I at least applaud you for not wanting just loud crap.... but i am kind of disappointed.... ewww sony gear :P

[norachelhere]

none of this stuff i actually went out of my way to get.
The sony sub and the old amp was in my coupe when I got it.... I'm not sure where the kenwood sub came from, it just showed up....
I understand that you can piece together a much better set up. I just use JL as the example because most people get the point.

[norachelhere]

addressing the original ? - you can open the amp up and modify the hardware to produce more output at a cost of heat and shorter life.

Usually there are a set of POTs or resistors that set the nominal voltage for the switches that can be changed. If you are bold enough to open it up, post a picture(high res) and I'll point them out to you.

Will do. Is it actually that "scary?"

I'll get those pics up as soon as I have a moment to take it apart.
thanks this is exactly what I was looking for.

[Notladstyle]

Will do. Is it actually that "scary?"

I'll get those pics up as soon as I have a moment to take it apart.
thanks this is exactly what I was looking for.

scary? no.

Will it catch on fire? maybe.

it depends on the build quality of the amp and the components used. You could make a 100 watt amp throw out 400 watts, but if the fets aren't designed to channel the current and dissipate the heat they will simply melt the pcb board or catch on fire(or both).

[TBSpyder]

Don't open you amp. Don't try to "tweak" it. Trust me. It's retarded to even consider it unless you hold an electrical engineering degree and have atleast a few years of car audio experience under your belt. Be happy with what your amp does for now until you can save up for a better one.

[the727kid]

Right now, I've got a sony 150watt and an off brand 150 watt.
I wasn't planning on keeping these. I just thought it would be fun to play with for a bit. you know the whole learning by doing/messing it up.

I'm a fan of JL audio, I really like the sound of a JL system. but again, I don't know enough to look at a spec sheet and decide whats good.
I would rather have a "perfect" sound instead of being record setting loud..... Don't get me wrong I like loud, but sound quality is more important to me than sound quanity.


How much you looking to spend?

I think your first step achieving SQ is go buy a roll or two of deadner (I prefer RammMat).

[Notladstyle]

Don't open you amp. Don't try to "tweak" it. Trust me. It's retarded to even consider it unless you hold an electrical engineering degree and have atleast a few years of car audio experience under your belt. Be happy with what your amp does for now until you can save up for a better one.

if its a garbage amp and hes electrically inclined it would be a fun project. like a welcome to car audio bonfire.

[POST]

if its a garbage amp and hes electrically inclined it would be a fun project. like a welcome to car audio bonfire.

its a she, and i don't think it'd be a very fun project to her since she'd go from having at least a poopy little system to nothing. maybe if she got a replacement amp, it'd be much better because then she wouldn't have to worry about it at all? I'd do the same but i can definitely resell these amps.

[Notladstyle]

O shit its a she?! switching to leghump mode bzzzzzzzz

[norachelhere]

sorry guys, its not a she
she made the screenname forever ago and never really used it. So I started using it and it has no become my screenname. She uses it every now and again....

[norachelhere]

if its a garbage amp and hes electrically inclined it would be a fun project. like a welcome to car audio bonfire.

yeah basically.

I'm trying to make some time tonight to take this thing apart.
Are there connections that I can make better or anything like for this little guy to handle what I'm going to make it do. I don't know everything there is to know about electrical stuff.... nor the terminoligy.... but I've got the basic understanding, and the know how to solder properly and all that jazz.
You said something about fets....what?

I figure if I'm gonna do this, I might as well learn as much as possible about it.

thanks for the help guys

[Notladstyle]

http://tinypic.com/view.php?pic=4cwsai0

the chips under the metal bars are FET switches that actually channel the high current signal to the speakers they drive. They create a lot of heat which is usually the cause of their death.

As you can see from hte pic they are bound on both sides by metal heatsinks which channel hte heat away from the chips to hopefully be absorbed by outside air. if you boost the AC voltage they are channeling they will of course put out more wattage but most amps are manufactured at their thermal limit already so the life of a modified amp is very short.


At least on that MTX amp, by replacing the large blue resistors with lower value resistors I was able to take the 470 it metered originally to somewhere around 900w on a 100hz sine wave. It only lasted a day or two before the pcb board melted

[norachelhere]

i see. So is this an internal kind of heat that you can't really do anything about, or can you so something like rig a fan up to it to make them last a little longer?
I don't know that I would do it, but we had an overclocked pc that we rigged up a water cooling system. think that would be of any benefit in this case?

[POST]

i see. So is this an internal kind of heat that you can't really do anything about, or can you so something like rig a fan up to it to make them last a little longer?
I don't know that I would do it, but we had an overclocked pc that we rigged up a water cooling system. think that would be of any benefit in this case?
you're looking at spending a lot of time, effort, and money on a piece of shit sony amp that you could easily replace for the same money you'd spend "overclocking" it.

[norachelhere]

time and effort i don't mind.
But if I have to buy anything then i'm just gonna walk away. I'm just trying to learn the possibilities. better to have a working understanding instead of a bunch of knowledge. ya know

[POST]

time and effort i don't mind.
But if I have to buy anything then i'm just gonna walk away. I'm just trying to learn the possibilities. better to have a working understanding instead of a bunch of knowledge. ya know

you're going to have to buy something to help cool the parts and keep them from overheating

[TBSpyder]

If only it were that easy. I've worked in car audio for several years, and the majority of the well experienced installers I know wouldn't even attempt this. I can pretty much tell you now, it's not going to be successful.

[Notladstyle]

Fans woundt help - you could bore 3mm holes through the heatsink and pipe cool water through similar to an engine block but that would be insane work since the cores of the chips would still be above their electrical design and would die eventually anyways.

[norachelhere]

well it seems like this whole idea has come to a screeching hault. The amp that I was gonna use isn't working...or i think its the amp. we set everything back up just for shits and giggles. It works...kinda at a very low volume level. Once you start to turn it up any, it starts to tweak. The sub makes a strange "pulsing" noise, and the amp does its self protection thing, the little red light turns on. A moment later, it trys to go back to normal, tweaks again. Its a horrible cycle. The amp gets really hot really fast. This whole process took 20 to 30 minutes and the amp felt like it was running all out all day.
did I forget something on the install?
or is something just busted?
thanks for the help

[norachelhere]

oh and one more question, what is "REM?"
from what I can tell its just a ground, but the amp already has a ground....

thanks again

[POST]

oh and one more question, what is "REM?"
from what I can tell its just a ground, but the amp already has a ground....

thanks again

REM is the remote lead. Not a ground.



For the other question, did you set the subwoofers to a lower resistance?
Put them back :P

[norachelhere]

REM is the remote lead. Not a ground.



For the other question, did you set the subwoofers to a lower resistance?
Put them back :P


remote lead, what do you mean?

I followed the wire all the way back to the front of the car. I thought it was gonna go into the head unit, but i was surprised to find that it was grounded out on the shifter. The amp has to have it to turn on, but i don't quite understand why.

I also figured out what was causing the weird tweaking issue.
For some reason, the amp won't bridge like it used to. It was designed for it. It is working off of the left channel. When you try to add the right channel, it just tweaks out. I'm thinking that it just got old and the right channel got worn out.... but what do i know.

and just to affirm the fact that I'm probably one of the newbiest newbs, I didn't know you could change the resistance of the subs. How does one go about doing that? and why would you want to?

[POST]

ok... wow this is scary. I might've said something that confused you... but lets try this:


The remote lead: It sends a 12v signal from your headunit usually to turn the amp on

Reason for having it? so the amp isn't always on and draining on your battery.

How it works? You tap it to the headunit's 12v power lead and what it does is it sends a "hey i'm turned on" signal and it switches the amp on to process the inputs and send out the boosted signals..

As for why it was grounded out on the shifter.... wtf????


Check your wires over again, something really sounds screwy.

You can't really change the resistance of the subs.... not the way you're talking about anyways. What i meant was you present a different load to the amp. Whatever way you wire up the subs is the way you present a load to an amplifier, whatever you have it set to right now is too low for the amp, and is throwing it into protect mode so it doesn't melt and cause a fire in your trunk ;)


Now you'll get a few guys right after me going into way more detail than necessary to refine my rather rough answer(s).

[norachelhere]

ok... wow this is scary. I might've said something that confused you... but lets try this:


The remote lead: It sends a 12v signal from your headunit usually to turn the amp on

Reason for having it? so the amp isn't always on and draining on your battery.

How it works? You tap it to the headunit's 12v power lead and what it does is it sends a "hey i'm turned on" signal and it switches the amp on to process the inputs and send out the boosted signals..

As for why it was grounded out on the shifter.... wtf????


Check your wires over again, something really sounds screwy.

You can't really change the resistance of the subs.... not the way you're talking about anyways. What i meant was you present a different load to the amp. Whatever way you wire up the subs is the way you present a load to an amplifier, whatever you have it set to right now is too low for the amp, and is throwing it into protect mode so it doesn't melt and cause a fire in your trunk ;)


Now you'll get a few guys right after me going into way more detail than necessary to refine my rather rough answer(s).

thats what I thought/was able to find out about the REM. But it is definatly grounded. The only wires that start at the head unit and go to the amp are the input wires. the ground goes from the amp to the chassis (under the back seat) then there is the power that goes from the battery to the fuse, to the amp. then the "REM" which starts at the amp, follows along side the power, and eventually ends up under a bolt on the shifter. It doesn't make any since to me at all. If they were just gonna ground it off, why not put it closer to the amp? Its like they thought it was gonna go to the head unit, and when they got there, they found out otherwise and just put it under the closest bolt. The amp won't turn on with out the REM wire, but it doesn't make since to me as to why..... just one of those things i guess we'll never know....

here's a question as to sub/amp set-up.
we start at the amp. we then go to subA. from there we go to subB.
First, would that work? Second, would subB get the left over power that subA didn't use? or do I not quite understand yet?
How about this one: Start at the amp. go to subA. Start at the amp, go to subB. What would happen if subA and subB where then connected? would that be the same as bridging, or again, do I not quite understand yet?


I really appreciate the help guys. I apologize for the newbness. I'll get it sooner or later.

[TBSpyder]

It all depends on how many voice coils your subs are, how many ohms each voice coil is, how many channels your amp has, and what the amp is stable to.

[norachelhere]

The subs are single voice coils, i don't know the ohms.... it has two channels, (75x2). The amp is supposed to be bridgeable,
The idea was to bridge the two channels and do one of those set ups. One sub is a 150watt (max) sony xplode, and the other is 150watt (max) Kenwood. The sony was in my coupe when I got it, and I found the Kenwood. So I don't really know alot about them other than the obvious.
The amp is older, but its a trooper. We've put it through all kinds of hell and it just keeps on keepin on. I don't think the company is even around any more. Fultron competition 75wattx2 bridgeable.

[TBSpyder]

Assuming the amp is a POS, your safest (and easiest) bet is to wire each sub to a single channel the amp.


General rule of thumb is to not run two different subs in the same setup. Usually sounds like shit. Another tid bit of info..."max" power is useless. Look at the "RMS" power rating...this is the recommended "continuous" power rating. Same goes for amps.

[TBSpyder]

Otherwise, you could wire your amp to 2 ohms...which is what this diagram shows. You use the positive of one channel on the amp and the negative of the 2nd channel on the amp. The amp may be marked showing exactly what terminals are used for bridging, check it.

[POST]

It doesn't make any since to me at all. If they were just gonna ground it off, why not put it closer to the amp? Its like they thought it was gonna go to the head unit, and when they got there, they found out otherwise and just put it under the closest bolt. The amp won't turn on with out the REM wire, but it doesn't make since to me as to why.....

Do you actually talk like how you're spelling that word?

You know its spelled "sense". And pronounced with a soft e.

The subs are single voice coils, i don't know the ohms.... it has two channels, (75x2). The amp is supposed to be bridgeable,
Since when do subwoofers have two channels?

[Notladstyle]

it sounds like you are using a speaker level output into the amp. I bet you just have some bad wiring in there that could be fixed easily.

Ill be around palm harbor tomorrow with my tools so if you want me to take a quick look at it maybe we can pinpoint the problem.

[norachelhere]

Do you actually talk like how you're spelling that word?

You know its spelled "sense". And pronounced with a soft e.


Since when do subwoofers have two channels?

i don't know why, but when i type, words just come out a bit wrong, its like my brain thinks faster than my fingers or something retarded like that. I know the word I want to type is sense, but my fingers end up typing since. I just need to make it a habit to re-read what I've typed and correct it.
as for the answers, I was just answering each question in order. i probably should have pointed that out better. thats what I get for rushing through.

[norachelhere]

it sounds like you are using a speaker level output into the amp. I bet you just have some bad wiring in there that could be fixed easily.

Ill be around palm harbor tomorrow with my tools so if you want me to take a quick look at it maybe we can pinpoint the problem.

I have no doubt that there is a wiring issue somewhere. I didn't set any of it up. The car just had it when we got it.

some help would be great.
hit me up with a pm and we'll come up with a plan.
thanks