I just installed my DLS A7 amp, and am experiencing hiss in the tweeters. It's not alternator whine, as it also exists when the car is off. The hiss level remains the same regardless of volume, and exists when the volume is set at 0. It's not a tremendous amount of hiss, but it exists nonetheless.

When the gains are set to minimum, the hiss (mostly) goes away, but if I adjust the gains upward even a little bit, the hiss is prevelant. I know how to properly set gains, so it's not a case of "too much" gain.

I've checked all my connections, verified good ground on the amp, have the rca/speaker wires separated from the power lines as much as possible, and have switched the channels that the tweeters are connected to and still get the same amount of hiss.

If anybody else has experienced this when installing amps in the TL, please let me know how you rectified it. Perhaps it's something inherent in the TL, and hopefully somebody(s) has found an easy fix.

Thanks in advance.

 

what else is the amp hooked up to?

 

On the input side, it's the stock HU to David Navone LOC's (from the front L&R and sub channels). The hiss is the noise floor of an active component...the LOC's are passive components and cannot cause hiss. So it would have to be coming from an active component...either the stock HU or the amp. I have all of the HU settings at "flat".

 

the noise is coming from the amp, you most likely need to put a cap on the tweeter or the noise is being caused by the crossover in your seperates

 

If you disconnect the amp from the HU do you still have hiss? If no hiss then it's coming from the HU. If you still have hiss then it's coming from the amp.

Which Navone LOCs do you have? I have the NE774 and the output voltage can be adjusted.

 

Unfortunately I can't disconnect the amp and test it without doing some major rewiring, although I may have to if I don't find a solution.

I have the NE7V for the mains, and an N85V for the sub...both adjustable and now at "max" setting per Dave's recommendation.

 

Can you disconnect the DSL amp from HU at the stock amp location? The output plug (going to the LOCs) from the stock amp will do the trick.

 

Try swapping the front/rear channels to check if there is something wrong with the LOC.

My system install is still in progress. I first just used the speaker level inputs on my amp and got terrible hiss at even the lowest gain settings. Even if I turn the head unit off, (aftermarket amp still on), there is still hiss coming from the speakers. So I decided to try a walmart LOC and got a little better results, but I have to keep the gains at minimum on the amp to keep the hiss subdued.

I haven't been able to narrow it down yet. I got a 3sixty and some new amps on order, so I hope that when rewire for them I'll be able to find the culprit.

 

I disconnected the amp from the signal, and the noise goes away. This narrows it down to a problem with the signal coming from the HU. There are obviously no gain controls on the oem HU, so I don't know what to do about that. The only other thing I can think of to try is to re-do the connections from the oem speaker levels to the new lines running to the LOC. Since the LOC is passive (thus can't create noise), it's got to be in the connections since there was no noise when stock.

 

There is noise even in the stock system and its likely coming from the stock amp or the head unit wich u wont be able to do anything against. I tryed the locs and then 3sixty same thing pretty much. The noise gets amplified with it especially if you have a strong amp. Im using a kicker sx900.4 amp wich is a high quality amp and one of the more exspensive out there and still get hiss. Its something that bothers me but u cant really hear it when the music is on so i got used to it. i just wish i could put an aftermarket head unit i would do it in a second but it would really look out of the place. and i also put a switch for my remote turn on so when i want it completly off i just switch it off since the stock amp is constantly on because of that HFL thing so u would hear the hiss even if the head unit was off. So yea i guess it must be coming from the stock amp.

there is one guy who did put an aftermarket unit but had a dash kit made for it wich came out really nice if i could find something like that i think i would do it to

 

King of Pain, do you not get any noise/hiss in your setup?

I got the 3sixty this week, but it was DOA, so I was unable to test it. However, I started wiring. I took the preamp wires that feed into the stock amp and spliced in some RCAs. Since the 3sixty was dead, I just hooked them directly into my amps (my amps claim they can handle .5V or lower). I don't hear as much noise, but it doesn't sound quite right either. It has a flat or hollow sound to it compared to the LOCs I was using post amp.

 

The only hiss or noise I get is whatever is on the source material itself.

You are getting a signal to the amps but it is very low. Not enough for the amps to use effectively. The 3sixty or the LOCs are needed to boost the signal into something the amps can handle. I think the Navone LOCs boost the signal to 9.5V.

I don't want to hijack this thread but I'm in the process of replacing my amps. My JL Audio 6 channel Amp has developed heat death in a couple of channels. As soon as the amp warms up a couple of the channels start to fade.

Oh Well,

Time to upgrade. I just picked up an Alpine PDX.4-100. I'm getting a PDX.1-600 later this week. Next will be a TC Sounds "TC-1000" (Maybe a JL Audio) 10" or 12" subwoofer.

Sometime around the middle of June I'll redo the trunk again. I have some new design ideas I want to try.

I'll post some pics when I'm done

 

KoP,

What LOC's are you using? Also, did you catch the stock speaker outputs at the oem amp and run lines to the trunk where they're connected to the LOC's?

Did you do any additional grounding of the stock HU?

Thanks.

 

The LOCs are Navone;

The NE774V for the 4 corners
The NE7V for the center and the sub

The wires run from the OEM amp to the trunk where the LOCs located. Short stringer RCAs (1 meter) go from the LOCs to the amps. I soldered and shrink tubed every single speaker and LOC wire connection. The stock amp and HU are left alone. I used the same gounding point in the trunk. All wires have been double check to insure there are no kinks or hard bends as they travel to and from the trunk.

 

That's the same basic setup as I have, but I've yet to solder and heat shrink all of the connections...which was going to be my next step.

Are you connecting the ground wire on the NE7V?

Thanks for the help.

 

King of Pain,

Also, how do you have the gains configured on the LOC vs the amp? Is it maxed on the LOCs?

 

I ran some new wires today. I just used some 16 guage speaker cable I had from walmart. I chopped off the gray connector at the stock amp, which has the speaker outputs. I then hooked up the speaker cable, and ran it along the passenger side of the car, under and behind the back seat, and into the trunk. Here it feeds into a cheap LOC (also from walmart), then RCAs that go into the AMP.

I was able to finish one channel before I ran out of daylight, but it sounds great! With my previous setup (using stock harness and wiring), with only the rear right channel active, you could clearly hear the hiss when seated in the drivers seat even at volume 0. With the new wiring, you can't hear any hiss. Even if you put your ear right onto the speaker, it sounds fine. Note, I used a digital multimeter with both setups to tune the gains properly, so I know that was not the culprit. I believe the new wiring with nice thick gauge did the trick.

I'll try to wrap up tomorrow after work and post feedback. Right now, its just patch work with some shoddy electrical taping holding it together, but it sounds really good! I'll do it for real tomorrow with some solder and heat shrink. I need to fix the preamp (black) connector as well, from my previous attempt.

Depending on how good it sounds, I might be able to avoid the 3sixty altogether.

 

The gains on the LOCs are at max. The amps at their minimum. The smaller LOC is grounded.

I installed the Alpine amp a couple of days ago and it sounds crazy awesome. Not sure what I'll do with the center channel yet.

 

I don't know what to try next. I re-did all of my grounds, and rewired every connection from the oe speaker outputs to the LOC, and I still get a bit of hiss.

 

What happens when you disconnect the wire at the stock amp location? Leave the LOC connected on the other end.

What kind of wire did you run?

 

When I disconnect the signal, the hiss goes away...which tells me that the noise is not in the DLS amp...it's coming from the stock signal.

I'm using Knukonceptz speaker wire and RCA's.

 

I finished hooking up the rest of the channels, and the hiss is now back on all channels (including the one that was fine before). I think this means the interference is being self induced. By this I mean, the wires are causing interference amongst each other. Since the wires are carrying high power, they have enough ampages/voltage to interfere with the signal on wires laid close to it. And since the wires are carrying pretty much the same sound signal, this amplifies the problem and is causing the noticable hiss.

To test this out on your setup, cut all the channels except one that has the hiss problem at the stock AMP. Is the hiss gone now or subdued?

 

You guys are scaring me with this noise/hiss issue.

I'm going to be doing the same install in the near future. One thing that will be different in my setup is that the LOCs will be in the front. When I ordered my Elemental Designs gear the guys there suggested I put the LOCs in front and run RCAs to the rear, the reason being that RCA cables are better shielded than speaker wire. I hope this prevents hiss in my system.

Greengecko ran his system with LOCs at one point. I wonder if he had hiss? Hopefully he'll chime in.

I'm sure there are alot of others here with similar LOC setups. What have you guys done to prevent hiss, or what did you do to get rid of it if you had it in the first place?

 

I have a hiss in with the stock HU and amp. I do have infinity speakers and tweeters... I dont remember it being there before...

I dont know if I want to amplify that... I think that hissing could be be as bad as humming, and that pisses me off.

 

I tried moving the LOC upto the stock amp area to keep the speaker wire run shorter, but the hiss is still there. There goes my theory on the self induced noise.

Maybe the folks without hiss just have their gains on the amps turned way down. This will get rid of most of the hiss, but in my case, it also meant sacrificing a lot of power. The amp is putting out no where near its average RMS specs according to my digital multimeter.

I think I'm giving up on the LOC route. I'd still like to try a line driver on the preamp inputs. I think the 3sixty could be used as a line driver. Anyone try this yet on the HU preamps, how does its sound?

 

im using the 3sixty and still have the same problem. as u said people that dont have the hiss i dont think they are using the full potential of their amp. And of course if you have a high powerd one then it gets worse. I think there is no way around it there is hiss in the stock system. Just hook the speakers directly to the stock amp and you.ll see. If someone made a dashkit for our car i would go with an aftermarket headunit in a second.