Newsgroups: rec.audio.tech
Subject: Re: Hum from mac C26 pre-amp
References: <[email protected]>
[email protected] writes:

> I would appreciate any ideas to help me track
> down a hum noise coming from my speakers when
> driven by a mac C26 preamp. The noise is in both
> channels the level does not change when the
> volume is turned up or down also it does not
> matter what input is selected.

The most common reason for humming in audio equipments:

1. Ground loops related humming
   - for information how to solve those take a look at
     http://www.hut.fi/Misc/Electronics/docs/groundloop/
2. Magentic or capacitive pickup on equipments or cable
   - move noise sources away
   - use well shielded cables and keep them away from noise sources
   - use good quality equipment
3. Broken equipment
   - get it fixed or buy new one

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