Hiss from Amp w/ RCA disconnected?

[joshpoints 10+ year member]

So I installed a new system and am running into a problem I've never had. I get a hiss at zero volume on the head unit coming from the speakers hooked up to the amp. I then disconnected the rca's to that amp and the speakers are still making a hiss with the engine off. Am I correct in presuming the amp is defective? The hiss is extremely loud. I previously pumped the speakers through the head unit amp with no hiss problems at all. Thanks.

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[Canaan 10+ year member]

Sounds like a bad ground.

Check the HU and amps grounds.

 

[joshpoints 10+ year member]

Sounds like a bad ground.
Check the HU and amps grounds.

It can't be the HU correct, because the hiss happens even when the amp has the rca's disconnected from it.

 

[pawn man 10+ year member]

sounds like you have the gains too high.

 

[joshpoints 10+ year member]

sounds like you have the gains too high.

I'll check that today, only thing is I can max out the volume on the deck with the current gain settings and the speakers don't distort at all. If I still hear the hiss with the gain turned all the way down would you agree it is the amp?

I have had alternator whine and things on previous installs that I had to troubleshoot but this hiss is happening with engine off and the engine on doesn't make it any worse. And unlike my previous issues this is a hiss rather than a whine.

 

[WKD TC]

what kind of amp is it

 

[joshpoints 10+ year member]

what kind of amp is it

It's a Lanzar Opti Mini Digital Amp.

As suggested in the thread, I turned the gain to its min setting and the hiss was still there.

 

[pawn man 10+ year member]

might be a problem with the amp.

 

[vario 10+ year member]

Definitely try regrounding the amplifier. The rca's on the amp probably are grounded poorly internally and having the amp not ground properly in itself compounds it.

 

[joshpoints 10+ year member]

Definitely try regrounding the amplifier. The rca's on the amp probably are grounded poorly internally and having the amp not ground properly in itself compounds it.

I was talking to someone and they said it could be a bad ground. They said a great way to test this was by running a wire directly to the negative battery terminal from the amp. Any comments regarding this?

I actually grinded the paint off the grounding point with a dremel tool before bolting down the ground for the amp.

 

[Cpyder 10+ year member]

I have a Lanzar amp and I get a hiss only when the RCAs are disconnected. Really weird. I actually had a lot of problem with my electrical system blowing fuses with my Lanzar amp. I even had a professional look at it and he was stumped as well. Funny thing is: it fixed itself after about two weeks. Give it some time. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[joshpoints 10+ year member]

now here is something strange! So I'm sure some of you are familiar with the loud kinda screeching sound that you here when you are trying to play a scratched disc and the cd doesn't skip but you can hear the laser struggling to with the cd. Well the amp reproduces this sound when through the speakers even when the rca's are disconnected. I'm thinking maybe somehow the ground is picking up this noise and sending it to the speakers? In other words a bad ground. I'll try playing with the ground this weekend.

 

[joshpoints 10+ year member]

So I hooked up an ED nine.2x in place of the lanzar amp and the hiss was all but gone to the point where it wasn't noticed.

I also noticed that if I use the low pass filter the hiss all but dissappears; only problem is I'm using the amp to power my components.

Do you think the Lanzar mini amp Opti2x300D is just a loud amp or do you think it is defective?