Newsgroups: rec.arts.theatre.stagecraft
Subject: Re: humm
References: <[email protected]> 
"David Lee"  writes:

> [email protected] wrote...
> > Connected the lap top into a Soundcraft E8 mixer then to the power amp
> > and the sound was, well, fine. Decided that Lap Tops being Lap Tops, I
> > had best keep the charger plugged in and then Humm. Turned off the
> > stage lighting circuits - in the same control cabin as the sound, still
> > had Humm. Waved the charger around to move it away from mains cables -
> > Humm.
> > Switched OFF the charger though still plugged in the wall - silence.
> 
> Could be worth trying an external USB sound card - particularly if you can 
> borrow one.  

In many cases when you use analogue interconnections or digital coaxial 
connection using internal or external USB soudn card does not matter. 
If the noise is related to groundign issues, there is generally not 
considerable difference if the sound card is sinde computer or outside. 
Typically on both of them the audio gorund is in contact with PC 
ground. 

There are only very foew external soudn cards that have inputs/outputs
that are isolated from PC ground. 

> I use a Soundblaster MP3 for anything critical since the sound 
> from the built-in card in my laptop isn't brilliant and, as usual, it 
> doesn't have a line-in.  Soundblaster also has an optical out so uploading 
> audio directly from my sound editing program to minidisc is dead easy.
> 
> I don't think that the MP3 is available anymore but I believe that there is 
> an improved version available for the same price or cheaper.
> 
> David 
> 
> 

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/