C5 > How much noise?
Pro
Joined: May 2007
Posts: 744
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From: WayTooCloseToNY Northeast PA
I see only three possibilities left...
1-The amp and deck impedances don't play nice
2-The Alpine has a noise issue (try an outboard AC>DC converter to power the Alpine and test then to verify) but it's unlikely
3-You never noticed it before (for any of a few different reasons)
1-The amp and deck impedances don't play nice
2-The Alpine has a noise issue (try an outboard AC>DC converter to power the Alpine and test then to verify) but it's unlikely
3-You never noticed it before (for any of a few different reasons)
Thread Starter
Team Owner
Joined: Feb 2000
Posts: 51,504
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From: Sacramento CA
1 - Maybe, kinda strange for two piece of equipment from the same brand. I'll hook up my old ARC amp to it tonight and see if it hisses.
2 - I did try headphones on it, with no noise, but... it's not designed to drive headphones, so...
3 - 0-bit noise check used to be part of what I did in an install, in the last 2 cars this was in. It was grave silent up to about 32/35.
2 - I did try headphones on it, with no noise, but... it's not designed to drive headphones, so...
3 - 0-bit noise check used to be part of what I did in an install, in the last 2 cars this was in. It was grave silent up to about 32/35.
Pro
Joined: May 2007
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From: WayTooCloseToNY Northeast PA
Last shot... use the same 0-bits track from another HU to drive the amp.
You've been through so many other system mods in the past couple weeks, I hesitate to say that it might even be related to that crossover issue we discussed, if that's still set up that way. That's a very remote possibility, but...
You've been through so many other system mods in the past couple weeks, I hesitate to say that it might even be related to that crossover issue we discussed, if that's still set up that way. That's a very remote possibility, but...
Melting Slicks
Joined: Aug 2006
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From: Tampa Bay, Go BUCS!!!Go Rays!!!Go Lightning!!!
St. Jude Donor '12-'13-'14
Hard to follow along here but is it hissing with a commercially produced CD? Maybe the problem is with the music you are putting on the cd or ipod from your PC???? Does it hiss using the tuner?
Thread Starter
Team Owner
Joined: Feb 2000
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From: Sacramento CA
Le Mans Master
Joined: Sep 2004
Posts: 5,707
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From: Los Angeles
Are you sure you don't just have your inputs set much higher than necessary on the amp? That's why I asked what the maximum numerical setting was on the HU. The mere fact that the hiss goes away when you put it in pause clearly rules out everything but gain structure, the HU or a noisy CD itself. I haven't seen an impedance mismatch in modern day equipment since the 70's. So I'm sure that's not the problem.
Thread Starter
Team Owner
Joined: Feb 2000
Posts: 51,504
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From: Sacramento CA
Are you sure you don't just have your inputs set much higher than necessary on the amp? That's why I asked what the maximum numerical setting was on the HU. The mere fact that the hiss goes away when you put it in pause clearly rules out everything but gain structure, the HU or a noisy CD itself. I haven't seen an impedance mismatch in modern day equipment since the 70's. So I'm sure that's not the problem.
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Le Mans Master
Joined: Sep 2004
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From: Los Angeles
Pro
Joined: May 2007
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From: WayTooCloseToNY Northeast PA
My vote is for the HU. There's most definitely a mute circuit in there (and has been for a long long time), so you have to run the 0-bits track. I'd hook up a different HU and see what happens before assuming the hiss is abnormal.
Thread Starter
Team Owner
Joined: Feb 2000
Posts: 51,504
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From: Sacramento CA
The pioneer 7800, same car, samp amp, hisses too, but only slightly, and the same amount of hiss all through the volume range until the last few ticks of the dial.
It MUSt be the head unit, strange it started when I put it in this car , though.
How do I make the HU stop hissing?
Max volume on HU is 35.
It MUSt be the head unit, strange it started when I put it in this car , though.
How do I make the HU stop hissing?
Max volume on HU is 35.
Le Mans Master
Joined: Sep 2004
Posts: 5,707
Likes: 4
From: Los Angeles
I know you don't want to but just for fun, try lowering the input level on the amps just a bit. You'd be surprised how much a tiny bit of input level can reduce hiss. It sounds like you've got plenty left over on your HU to make up for it.
Former Vendor
Joined: Nov 2005
Posts: 8,995
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From: Spring Texas
St. Jude Donor '08
If you have an Ipod or other MP3 player, get a 1/8"audio/RCA connector from radioshack. Plug your MP3 player into the amps RCA jack. If the noise remains, It's your amp, if it goes away it's either your headunit or a poor connection with the RCA cables.
Btw, what RCA cables are you using?
Btw, what RCA cables are you using?
Le Mans Master
Joined: Sep 2004
Posts: 5,707
Likes: 4
From: Los Angeles
Are you talking about the gains on the amps or the HU? If you turned the input levels on the amps all the way down and it still hisses then you've changed your story and therefore the problem lies in the power amps.
Pro
Joined: May 2007
Posts: 744
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From: WayTooCloseToNY Northeast PA
If you have an Ipod or other MP3 player, get a 1/8"audio/RCA connector from radioshack. Plug your MP3 player into the amps RCA jack. If the noise remains, It's your amp, if it goes away it's either your headunit or a poor connection with the RCA cables.
Btw, what RCA cables are you using?
Btw, what RCA cables are you using?
If you really want to dig into this, then swap the amp, then try powering the HU from an outboard source, then try a different HU altogether (which it sounds like you did with the Pioneer, but to be meaningful, everything else had to remain the same).
Thread Starter
Team Owner
Joined: Feb 2000
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From: Sacramento CA
When I say "gains" I'm talking about the gains on the amplifier.
When I say "volume" I refer to the volume setting of the head unit. I'm not using them interchangibly.
when I get home, I'm going to unplug everything bit by bit too. Ipod adapter, antenna, then if it still exists, I'll run rcas to an amp in another car that's already set up for this head unit.
I seem to remember reading somewhere, maybe some years ago, about someone getting hiss from his antenna.
Last edited by Kale; Aug 22, 2007 at 05:35 PM.
Le Mans Master
Joined: Sep 2004
Posts: 5,707
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From: Los Angeles
#6, #11, #20, #28, I mentioned that I tried it with the gains all the way down.
When I say "gains" I'm talking about the gains on the amplifier.
When I say "volume" I refer to the volume setting of the head unit. I'm not using them interchangibly.
when I get home, I'm going to unplug everything bit by bit too. Ipod adapter, antenna, then if it still exists, I'll run rcas to an amp in another car that's already set up for this head unit.
I seem to remember reading somewhere, maybe some years ago, about someone getting hiss from his antenna.
When I say "gains" I'm talking about the gains on the amplifier.
When I say "volume" I refer to the volume setting of the head unit. I'm not using them interchangibly.
when I get home, I'm going to unplug everything bit by bit too. Ipod adapter, antenna, then if it still exists, I'll run rcas to an amp in another car that's already set up for this head unit.
I seem to remember reading somewhere, maybe some years ago, about someone getting hiss from his antenna.
I assume then that you are still able to play music with your "gains" turned all the way down but the noise is still unacceptable? If that's the case, your HU is definitely abnormally noisy.
Pro
Joined: May 2007
Posts: 744
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From: WayTooCloseToNY Northeast PA
OK, gents, the frustration level is creeping up, so let's breathe.
That's radiated noise, and usually from an old antenna FM booster module. Nasty things those were. No way that's the problem here.
I gotta agree whole-heartedly there.
If you're running lines between vehicles, try the reverse while you're at it just to see what happens.
I assume then that you are still able to play music with your "gains" turned all the way down but the noise is still unacceptable? If that's the case, your HU is definitely abnormally noisy.
If you're running lines between vehicles, try the reverse while you're at it just to see what happens.
Thread Starter
Team Owner
Joined: Feb 2000
Posts: 51,504
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From: Sacramento CA
sorry, they are PDX amps. Never had an amp with a gain switch, thought that was just marine stuff.
Anyway,
Removed ipod connector, unplugged fm antenna, still get static. OK.
Connected RCAs to the amp in my other car - I still get the hiss.
the HU came from this car, so that amp is only there because I'm too lazy to pull it.
So, 100% for sure its the head unit, in this car. Strange, that it started so suddenly. I wonder if I did something to it when I put it in the car.
Anyway,
Removed ipod connector, unplugged fm antenna, still get static. OK.
Connected RCAs to the amp in my other car - I still get the hiss.
the HU came from this car, so that amp is only there because I'm too lazy to pull it.
So, 100% for sure its the head unit, in this car. Strange, that it started so suddenly. I wonder if I did something to it when I put it in the car.