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Discussion Starter #1
Hope you guys can help me.

I have a 9887 in my system and I recently had a judge comment that there is hiss on the system.

We tested with the IASCA zero-bit track and the hiss was completely gone.

So we left it there.

So over the weekend I started testing this again and there is definitely hiss on the system.

Now I can rule out the following.

- Its not my DLS RA50 amp. Previous HU was dead quiet and when I pause the Alpine its also dead quiet.

- Gains are set correctly. Nothing funny there. I lowered the gains and the noise is still there.

- Not imprint noise. Im not using it.

- Defeat is enabled.



Somehow I think its the HU.

Anything specific I should check?

Will a complete reset of the unit help at all?

Thanks
 

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*doh* I see it.

dumb question was: was Imprint activated with hiss on, de-activated with hiss off?


I've heard that the op amps in these have been riddled with the occasional noise to incluse those of the same series that was put in the H701. I'm also regurgitating in an effort to fix the *doh*.

I have it in mine too but only with Imprint.
 

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i only get hiss if i activate the EQ - with the defeat enabled i get no hiss - but i definitely do get some when the EQ gets used
 

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Discussion Starter #7
Its quite odd. Ill check with EQ on and off etc etc etc.

First thing is to reset the unit and try again.

See what happens.

Also need to check what happens when I switch the internal amp on again.
 

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internal amps are off on mine, still has the hiss. I'm thinking of running my speaker output to the amps and bypassing the RCA's. The actual amps may be better than the preamps:)
 

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Discussion Starter #9
Seems like its a faulty unit. Using a silent recording (Not zero bit) it hisses quite a bit. Nothing makes it go away. Once I enable blackout the hiss changes. The high pitch gets a little better.

Ai ai ai. Such is life.
 

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Just a blind stab in the dark... Have you tried a different/better ground to the headunit?
 

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Discussion Starter #11
Haha. Was about to post about that.

Just ran a new ground from the amp's grounding point to the HU. The power to the HU is directly from the battery with a second in-line fuse.

No difference.

Also did a reset on the HU with no success.

I will install an older 9835 on Wednesday to see if its something else in my system maybe.

Somehow I doubt it since when I pause the track playing the noise stops.
 

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Discussion Starter #12
Seems like the noise is related to the CD pickup on the deck

When I run digital aux in its dead quiet. Can't do the same with tuner obviously :D

Will test with iPod tomorrow but I suspect Ill get the exact same result.
 
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