Re: [LAU] Awful noise out of FA-66 -- SOLVED

From: Ken Restivo <ken@email-addr-hidden>
Date: Fri May 25 2007 - 02:35:11 EEST

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On Sat, May 19, 2007 at 11:40:16AM +0200, Pieter Palmers wrote:
> Pieter Palmers wrote:
> >Ken Restivo wrote:
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> >>
> >>I plugged my spiffy new linux laptop into an amp tonight and used it
> >>as an instrument with a band, using an M-Audio Axiom49 as a MIDI
> >>controller.
> >>
> >>Not everything works yet on this new machine, but what I needed most
> >>for tomorrow night's show (specimen, with a couple specialized
> >>samples), worked fine.
> >>
> >>Except for the noise. The FA-66 was producing the most awful, buzzy,
> >>glitchy digital background noise.
> >>
> >>I ran the following chain, and got horrible aliasing noise: Laptop ->
> >> ExpressCard Firewire -> FA-66 -> SWR bass/keyboard amp
> >>
> >>The FA-66 is powered by its wall-wart, since the ExpressCard doesn't
> >>power it (even though it is a 6-pin connector).
> >>
> >>My question is this. What's up with that awful noise?
> >
> >When googling around I found at least one other person having the same
> >issue with the FA-66.
> >
> >I've noticed similar noise at some places with my QuataFire line out's.
> >
> >Some things to try:
> >- unplug the power supply of the laptop (for test)
> >- put a DI box inbetween the amp and the edirol (enable ground lift)
> >- use another power supply for the edirol (preferably a transformer
> >based one).
> >
> http://docs.info.apple.com/article.html?artnum=86655
>

Thanks for your help! The USB M-Audio Audiophile exhibited the same noise problem. Then I unplugged the laptop's power supply and ran off of batteries, as you suggested, and there was blissful silence!

The problem was the power supply.

Any advice on brands/distributors of good *quiet* laptop power supplies? The cheap-ass "Delta Electronics" supply (19v, 3.6A) that came with the laptop obviously sucks, and the only other 19v laptop power supplies I have around here are only 1.8A.

- -ken
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Received on Fri May 25 04:15:10 2007

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