[LAU] Noise update, still the case with the other interface

[Pieter Palmers]

Ken Restivo wrote:
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> On Mon, May 21, 2007 at 07:45:29PM +0100, Folderol wrote:
>> On Mon, 21 May 2007 11:10:46 -0700 Ken Restivo <ken at restivo.org>
>> wrote:
>> 
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>>> The M-Audio Audiophile interface produced just as much noise as
>>> the Edirol FA-66 did. However, the amp I borrowed was buzzing
>>> even with only a regular (Korg) keyboard plugged in, so the
>>> problem may have to do with the amp.
>>> 
>>> I also noticed that this laptop's analog video output produces
>>> some nasty warbling/ghosting on my external monitor. Looks like
>>> rain falling or fog travelling rapidly, especially with dark
>>> screen backgrounds. Dunno if that's an improper X setting, a
>>> problem with the monitor, or or maybe this laptop is just
>>> generating way too much EMI with the Core 2 Duo's 2.33Ghz clock?
>>> I hope that's not the problem-- that is one of the few things I
>>> cannot change.
>>> 
>>> I've going to buy a keyboard amp, to isolate that variable at
>>> least. Off-topic, perhaps, but any recommendations? Most keyboard
>>> players I've seen recently seem to have Roland wedge-style
>>> keyboard amps. My local store carries the Peavey's (KB4, etc).
>>> 
>>> Thanks Pieter and others for links about noise mitigation. I'll
>>> try those suggestions too once I get the amp situation squared
>>> away.
>>> 
>>> - -ken
>> Have you thought of plugging in nothing except a battery operated 
>> headphone amplifier? With no external earth loops and a high
>> immunity to EMI pickup this could prove very revealing.
>> 
> 
> It sounds fine with headphones, and also sounds fine going into my at
> home stereo: quiet and lovely.
> 
> However, my stereo is *not* grounded: it has only a 2-prong plug.
> 
> Likewise, the wall-warts for both the FA-66 and the Audiophile are
> not grounded. Maybe I should try to find a grounded wall-wart?
> 
> How I wish these things were powered by their USB/Firewire cables!
> 
That wouldn't help (since they are all 2-prong). It's most likely the 
laptop PSU that causes the problem.


Pieter