I noticed when I change tracks on a cd or switch from cd to cd changer there seems to be a background noise or hiss. both units were professionaly installed but this head unit is a pre-amp head unit only--my other stereos I haven't noticed or maybe I'm being to thourough in sound. any comments or suggestions would be helpful. ( the amp is also Alpine and was professionally installed)


Thank you

Randy

 

and there is no ground loop either--that much I know!

 

I'm thinking there might be a ground loop - seriously, unless your amplifier and head unit share a common ground, the possibility exists. Also possible is that power was run alongside the signal wire. And while I've never used my S2000's accessory outlet, in other cars I've seen things like cell phone chargers add noise to a system.

If the stereo was indeed professionally installed, it shouldn't make noise, so take it back to whoever installed it and have them fix it.

Good luck!

 

At what volume level are you hearing the hiss? If it is at high volume levels it most likely will be the noise floor of the amp or head unit...you won't be able to do anything about it, except upgrade.

 

It is usually at high volume---I have the top of the line head unit from Alpine--7969 and the Alpine MRVT-407 V-12 amp.

 

I thought the top of the line Alpine was the 7990, which, like my Sony CDX-C90, has a copper chassis and fiber optic outputs for minimal noise. If that's what you were using you'd need something between the head unit and amp that takes optical input, which you don't list. So my guess is you're using RCA cables to run the signal to the amplifier, which is probably somewhere other than under the dash, and thus probably does not share a common grounding point with your head unit, which is why a ground loop issue is possible. And like I mentioned earlier, it's possible the power wires were run alongside the signal wires, which can introduce noise. Even the best-matched, highest-end components can sound poor if the install is done incorrectly.

If the noise is only at high volume and isn't that bad, I wouldn't worry about it. When I was amping the stock head unit my system would do that, and in a way, it's a nice warning that things are about to get loud when the song starts. These days I get no warning as things are starting up, and it can be painful when I forget how loud it was when I parked!

 

Make sure you have good connections between your head unit and your amp. If you are using RCAs, make sure that the outer edges are making good contact with the connectors on the amp and the h/u as these are grounded in the chassis' of the amp and h/u.

Make sure you have good grounds at both your h/u and amp. It does not need to be at the same point, but a good, clean connection to the chassis. The cars chassis then acts like a single ground point. As JZR says try to stay away from any wires that carry dc...this could even be wires to your rear signal lights. Fibre is alway good because electromagnetic noise cannot be introduced into an optical signal.

If it is still there, what you are mostly likely hearing is the noise floor of the head unit being amplified or the noise floor of the amp. In that case you are out of luck or need to spend more $$$ on more expensive equipment . However, the volume has to be very high in this case so it should not bother you too much, especially with the top down!!!

Hope this helps.

 

My H/U has copper sheilding and has the optical out put. I don't really notice it when I'm in the car driving---just when I am playing w/ the stereo w/ the car off. I did notice the remote lead was taped to the ground or power wire to the amp--do you think this might be it?

 

Okay, with the car off you are most likely hearing the noise floor of the amp or h/u. There is not too much you can do about this. I cannot say this is for certain because I need to hear it. To be on the safe side, either use the fibre output if you can, if you cannot, make sure you have good RCAs, if you want to make some yourself, use coax cable (the stuff for cable tv) as this will have good shielding. Finally make sure that everything is well connected, escpecially the outer parts of the RCA connector.

As far as the remote lead being taped to the ground or power lead, I am assuming you mean taped to it but not connected to it. This should be okay. The remote will carry +12 V when the head unit is on, this will trigger the amp to turn on...so it does not drain your battery.

Hope this helps....