AMP issues.....

[songforwhoever]

Hey Guys,

Have a 2 channel 100watt amp in the boot....my head unit is a Sony CDX-GT424U. I have tested the power lead at the amp end and there is a voltage of 11. (Seems fine to me???) I have a pair of JBL GTO-937 6x9's....

Now the problem....
I get power to the amp no problem....the speakers are wired up....the phono leads run from the head unit to the amp BUT no sound??

Any ideas guys!? Sorry to sound such a N00B!

)oe

 

[MT AUDIO]

remote and earth connected as you havent mentioned them

 

[wallop]

Voltage at the amp terminals should be within 0.5v of the voltage at the battery, a voltage reading of 11v is very poor.....esp poor if the engine was running during the test....

A battery displaying 11v is essentially flat and requires charging....

 

[songforwhoever]

Remote switch is connected and the earth is secured to the chasis of the car. Do you think that battery needs charging or the battery isnt capable of the load thats on it?

Thanks Guys

 

[wallop]

Remote switch is connected and the earth is secured to the chasis of the car. Do you think that battery needs charging or the battery isnt capable of the load thats on it?

Thanks Guys

Was the 11v reading achieved with the engine running or without it running???

If it's without the engine running then I would check all connections in the power supply circuit are good and tight....Esp at main fuse near the battery....

If reading was achieved whilst engine running then I would suspect a faulty fuse, (esp if AGU type used), a naff connection or very poor earth site....

I assume your using at least 8awg wiring for the power circuit & you've ADDED a new battery to chassis earth to match your new power cable....

Voltage at the battery with engine off should be around 12.8v, with engine running it should be around 14.4v, (although anywhere between 13.5v to 14.4v is considered acceptable)....

Voltage at amp terminals should be within 0.5v, if its more than this then you have a supply issue, (look at cable size, fuse holder connections, fuse itself, crimped connections & earth site/condition).....

 

[songforwhoever]

Remote switch is connected and the earth is secured to the chasis of the car. Do you think that battery needs charging or the battery isnt capable of the load thats on it?

Thanks Guys

Was the 11v reading achieved with the engine running or without it running???
***At this point the Engine was running, a reading of 11.59v was picked up from the amp end.***

If it's without the engine running then I would check all connections in the power supply circuit are good and tight....Esp at main fuse near the battery....

If reading was achieved whilst engine running then I would suspect a faulty fuse, (esp if AGU type used), a naff connection or very poor earth site....***Would it be worth changing the power cable running from the battery to the amp as this is the only thing I havent done?***

I assume your using at least 8awg wiring for the power circuit & you've ADDED a new battery to chassis earth to match your new power cable....***Can you go into a little more detail, would you suggest a higher performance battery?***

Voltage at the battery with engine off should be around 12.8v, with engine running it should be around 14.4v, (although anywhere between 13.5v to 14.4v is considered acceptable)....***Battery Voltage is excellent, checked out fine***

[QUOTE/]Voltage at amp terminals should be within 0.5v, if its more than this then you have a supply issue, (look at cable size, fuse holder connections, fuse itself, crimped connections & earth site/condition).....

 

[wallop]

***At this point the Engine was running, a reading of 11.59v was picked up from the amp end.***

^^^Way too low^^^

***Would it be worth changing the power cable running from the battery to the amp as this is the only thing I havent done?***

^^^Without knowing what size cable your using, or the type/size of in-line fusing, I couldn't say....Exactly where is your current amplifier earth site??? This is more than likely the culprit^^^

***Can you go into a little more detail, would you suggest a higher performance battery?***

^^^No point upgrading the battery until the boot voltage is sorted....With regards ADDING extra battery earth, the return path back into the battery is just as important as a correctly sized power feed cable, if you fail to ADD the extra earth a bottleneck will occur at the battery earth location, (usually called a 'point of high resistance').....

***Battery Voltage is excellent, checked out fine***

^^^That's good news, I assume it checked out OK with engine off & on, indicating a good charge circuit^^^

I would be inclined to suspect;

1, Amplifier earth site....
2, Power cable, (faulty fuse, loose connection, or simply too small)....