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#195150 - 28/12/2003 14:35 Karma docking base RCA out sound quality.
MiloDC
journeyman

Registered: 19/09/2000
Posts: 57
Sorry if this has been discused before, or if it's in a FAQ somewhere.

Anyone else getting extraordinarily crap sound using the RCA outs on the docking base?

I am hearing noise big time. (Interference from the Ethernet and/or USB hardware, perhaps?) It is unusable.

Just strange, given the great sound quality coming out of the stereo mini jack on the Karma itself.
_________________________
-- Milo D. Cooper http://www.miloonline.net/

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#195151 - 28/12/2003 14:38 Re: Karma docking base RCA out sound quality. [Re: MiloDC]
CrackersMcCheese
pooh-bah

Registered: 14/01/2002
Posts: 2489
Are you running the RCA's through an amp or just through earphones?

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#195152 - 28/12/2003 14:46 Re: Karma docking base RCA out sound quality. [Re: CrackersMcCheese]
MiloDC
journeyman

Registered: 19/09/2000
Posts: 57
PhilipOHare: Are you running the RCA's through an amp or just through earphones?

An amp. They're plugged into my Yamaha mini system.

These are the same cables I use to plug my Empeg into the mini system. I hear no defects when my Empeg is plugged into my Yamaha via the RCA cables.
_________________________
-- Milo D. Cooper http://www.miloonline.net/

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#195153 - 28/12/2003 15:00 Re: Karma docking base RCA out sound quality. [Re: MiloDC]
CrackersMcCheese
pooh-bah

Registered: 14/01/2002
Posts: 2489
Do you have a phono adapter to check if the noise is there with just earphones from the RCAs? That could rule out the docking station.

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#195154 - 28/12/2003 15:05 Re: Karma docking base RCA out sound quality. [Re: MiloDC]
MiloDC
journeyman

Registered: 19/09/2000
Posts: 57
It is definitely the USB.

Playing classical MP3's that I ripped at 320Kbps, I get noise the instant I plug the USB cable into the docking station. I don't even have to plug it all the way in.

When I remove the cable, the noise stops immediately.

The Ethernet cable produces no noise.

Now I *really* want to ditch the USB cable. Let's get that Ethernet performace up to snuff, Rio.

Incidentally, though not surprisingly, the sound quality coming out of the RCA jacks is still inferior to the stereo mini sound, to my ears. Anyone concur?
_________________________
-- Milo D. Cooper http://www.miloonline.net/

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#195155 - 28/12/2003 22:51 Re: Karma docking base RCA out sound quality. [Re: MiloDC]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31600
Loc: Seattle, WA
When I remove the cable, the noise stops immediately.
The Ethernet cable produces no noise.
You've probably got a good old fashioned ground loop, then. I'll bet that the problem goes away when you unplug the AC adapter as well. There's also a chance the noise would go away if you routed the RCA's into the line-input of your computer's sound card instead of sending them straight to your amp.
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Tony Fabris

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#195156 - 29/12/2003 04:13 Re: Karma docking base RCA out sound quality. [Re: MiloDC]
rob
carpal tunnel

Registered: 21/05/1999
Posts: 5335
Loc: Cambridge UK
Incidentally, though not surprisingly, the sound quality coming out of the RCA jacks is still inferior to the stereo mini sound

According to the signal analyser the RCA outputs have slightly better audio quality than the jack output (at least in terms of SNR).

Rob

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#195157 - 31/12/2003 05:11 Re: Karma docking base RCA out sound quality. [Re: MiloDC]
altman
carpal tunnel

Registered: 19/05/1999
Posts: 3457
Loc: Palo Alto, CA
Yep, as Tony says - that's a ground loop. Not having to plug USB in all the way is a tell-tale sign - the shield touching is enough to hook the earth of the player into the PC's earth.

Ethernet is isolated (all ethernet devices are) hence doesn't suffer from this way.

The RCA out audio numbers are better than the ones via the headphone out (no distortion from the headphone amp) - maybe it's just a listening preference?

Hugo

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