29424Re: V9 output to audio card?
- Jan 2, 2009--- In firstname.lastname@example.org, "Alan" <g4zfq@...> wrote:
> ----- Original Message -----
> From: "Ken" >
> > By "mains frequecy" you mean the 60 (or 50) cycles of the power line?
> Yes, I thought I was talking the wrong language! Over here we often
> 50Hz main power supply line "the mains"small value
> > A "lowish" value (such as in the pF range?)
> That depends on the frequency and the line impedance. 10nF is a
> at 50/60Hz so offers a considerably higher impedance than the directthrough
> connection via the audio cable. Therefore little LF current flows
> the capacitor.there. If it
> > while allowing the "spiky" USB signal to pass....
> > Is there any signals as such on the ground wire of the USB connection?
> The spiky USB signal has to return to ground, so yes, they are
> is a good low-resistance ground connection they will not be noticed.cable then
> > AND does the ground wire not need to be a DC ground that would be
> > blocked by a capacitor?
> The DC ground is connected via the audio ground.
> > are you suggesting putting this "lowish" value capacitor on all the
> > USB wires to isolate them to prevent any ground loops?
> If there is a good ground return to the USB by way of the audio
> this capacitor may not be needed. I leave the USB grounddisconnected to
> avoid a ground loop at low frequencies. The 10nF capacitor justgives the
> spiky signal an alternative route.that to
> Again I stress that this is just the way I have done it. It seems
> get the best results it may be necessary for people to experimentuntil they
> are satisfied, their conclusions may differ from mine .Ah, the brits and the americans - two peoples separated by a common
> 73 Alan G4ZFQ
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