replaced audio.. Now amp goes into safety mode

[-T8-]

Stripped my old galant of all the audio equipment and put it in my new car.
It worked fine in the galant but in the wrx if i turn the volume past a certain point or the song gets "bassy" then the amp shuts down.
If i turn the car off and then on again then the amp works, until the volume is turned up.

The amp has an LED light which when opperating is green but goes red when it shuts down.. Some sort of safety feature... But i cant figure it out.

I dont have the instruction manual as its burrowed from a friend.
The amp is a 1400w boss 5 channel.

Could it be the car battery? Thats my only thoughts, it looks like a standard battery where as the galant had a good replacement one, but its over 3 years old anyway.
OH and in the galant the head unit only needed to be turned up to say 30 before it was loud.. the wrx has to be turned up to 50 to get to the same volume level and it shuts down then anyway

Any thoughts or help would be greatly appreciated

 

[cyber_scriber]

I don't think it has anything to do with the battery.

It sounds like the amp's protection is triggering, probably due to clipping.

Are your amp gains set appropriately? Remember, the gain knob is not a volume knob!

 

[Scubasteve]

Typically that would be caused by a poor earth, make sure the earth wire is the same guage as the power and that it is attached to the chassis even go to the trouble of removing the paint work for a good connection. As for the loudness that can be the difference in the quality of the head units or the dials may have been bumped on the amp.

 

[-T8-]

I havn't checked the any of the dials because they are all behind a compartment on the amp that needs a special key to open it (which i dont have )

So the gain, volume and anything else thats under that little compartment has not been changed. Might try source out a key and have a look though.
thanks Bruce

 

[-T8-]

Same head unit is being used.. Iv changed the earth to different locations around the car and no difference, but havnt removed any paint, makes me cringe thinking about that.. But ill try it.

 

[cyber_scriber]

If you're using the same head unit and amp as before (and assuming the gains are the same), then you shouldn't need to turn the head unit volume to 50 to get similar volume to what you were previously getting at 30, even factoring in different car internal acoustic properties.

The idea of the gain switch is to simply match the head unit's output voltage. It is not designed to be turned up to give high volume with not much turning of the head unit's volume knob.

As James has suggested, make sure you improve your earthing. Then re-adjust your amp's gain settings.

Also, Boss 1,400 watt big bang amps aren't well known for the quality of the internal circuits, so it could also be an internal fault.

 

[steveP]

wont be the battery.

as stated, if the gains and HU are the same, then there is defiantly something wrong.
i would bet either the amp has been damaged in transit (being of Boss quality lol), or somewhere in the car theres a dodgy wire restricting current. (unlikely however). like u said, redo the earthing.. sand the paint off. and go over all wires and connections. theres something defiantly wrong.

and the gain knob is a VOLUME knob. it does exactly that, adjusts the volume. u just need to match it up with ur head unit so u have full range of the volume knob on the HU.

 

[cyber_scriber]

the gain knob is a VOLUME knob.

I don't think that's right.

Read more here:

http://www.mobileelectronics.com.au/forums/index.php?showtopic=35875

The relevant text:

"The gain control is NOT a volume control. Turning the gain up higher and higher does not produce higher ‘full-power’ output. If an amp produces a maximum of 100WRMS per channel, increasing the gain will not yield more than this.

Better to think of the gain as a ‘sensitivity’ setting: the higher the gain, the more sensitive the amp is to the signal fed into it."

Tate, read the above link as it is instructive on how to set your gains.

 

[steveP]

sensitivity setting.. lol thats EXACTLY what volume is. changing the volume doesnt adjust the power output. thats just silly.

somewhere along the lines people stopped refering to gains are volume.. and now they are trying to justify it. btw its not me saying this, its the broader audio community. ill see if i can dig some stuff up..

 

[ed84]

You swapped the speakers over also i take it?
I kno ive had similiar troubles before when i had a tiny strand of copper on the front left door speaker shorting out... Maybe worth checking amp terminals & speaker terminals - Just a thought! Also once i tapped into the factory speaker loom and forgot to cut the wires to the HU's amp so it didnt like that much - produced a similiar result, would work fine, then bad static, then nothing! luckily nothing was fried
And yeh gain does make it louder - but it is not volume.

 

[steveP]

"The gain control is NOT a volume control. Turning the gain up higher and higher does not produce higher ‘full-power’ output. If an amp produces a maximum of 100WRMS per channel, increasing the gain will not yield more than this.

sorry not to pick on u, but after re-reading that. it contradicts itself. adjusting the gain obviously does not increase or decrease the power output. so what what is it doing.. adjusting the volume.. duh!

 

[steveP]

http://www.teamrocs.com/technical/pages/gains.htm


ever since high school people were telling me gains are not volumes but they are something else which cant exactly be defined. i could never get my head around this until it was obvious they are volume knobs. anyone who knows how to adjust/tune amps will see the simplicity.

 

[cyber_scriber]

I disagree with you Steve and I think it's misleading to suggest that sensitivity and volume are the same thing.

Even the link you posted states that gains are to:

"adjust the incoming signal to the amplifier so the amplifier works well with your headunit of choice or to match the level of other amplifiers in your system"

Although his use of terminology refers to volume, the way he actually describes how gain works is not actually to do with volume but to do with sensitivity and signal matching.

However, we digress. Perhaps if you wanted to continue a "gain vs volume" debate, you could start a new thread in the car audio section. Better still, I would be very interested to see your theory being debated on Mobile Electronics Australia, which has thousands of car audio nuts!

 

[ed84]

ummm i forget ALL my amp theory so wont argue, but i think it is semantics.
You wont be cranking the gain every time a good song comes on so its not a volume control :-P.

And maybe you should invest in an Oscilliscope! haha

 

[steveP]

thing is people are very narrow minded and will only see it their way. they can call it a sensitivity setting or whatever, but what exactly does that mean.. that it adjusts the volume.

if u read the link about the volume control swing. thats the key. u want the amp volume set so that u have full use of the HU volume. thats all it does. especially when u have multiple amps. no amps are going to be outputting the exact same volume. and the gains fine tune this.

on paper and in theory u can debate it forever. but to actually get ur hands dirty and spend hours configuring amps (like i have), it will become so clear and obvious whats going on.

 

[steveP]

You wont be cranking the gain every time a good song comes on so its not a volume control :-P.

obviously not, as its in the boot.. however if u did, it would do the exact same thing as if u turned the HU volume knob up.. correct?

 

[cyber_scriber]

You wont be cranking the gain every time a good song comes on so its not a volume control :-P.

Agreed Eddie and a very good and simple way to explain it.

 

[ed84]

thing is people are very narrow minded and will only see it their way. they can call it a sensitivity setting or whatever, but what exactly does that mean.. that it adjusts the volume.

if u read the link about the volume control swing. thats the key. u want the amp volume set so that u have full use of the HU volume. thats all it does. especially when u have multiple amps. no amps are going to be outputting the exact same volume. and the gains fine tune this.

on paper and in theory u can debate it forever. but to actually get ur hands dirty and spend hours configuring amps (like i have), it will become so clear and obvious whats going on.

Just read it, i dont agree with his whole point of view.
Gain IS exactly that, to avoid clipping and hence protecting the amplifier, the speakers & your ears. But yeh, semantics.

SO, you see the only way the gains can be used to eliminate clipping or distortion will also limit your top end volume! And for most of us it is NOT DESIRABLE to do so.



Plus he is talking about tape decks LOL

 

[steveP]

u guys are so sure that gains are not volume controls, even tho admitting they make the volume go up. so what exactly are they.. sensitivty settings? thats another term for volume.. please elaborate..

 

[ed84]

to avoid clipping and hence protecting the amplifier, the speakers & your ears.