On 5/25/07, Ken Restivo <ken@xxxxxxxxxxx> wrote:
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Sat, May 19, 2007 at 11:40:16AM +0200, Pieter Palmers wrote: > Pieter Palmers wrote: > >Ken Restivo wrote: > >>-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 > >> > >>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
Have you tried groundlifting the power supply? Worked for me... until i found a better solution, throwing out the laptop and getting a desktop. ;) Loki _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-user
