kaufhaus Posted October 17, 2005 Report Share Posted October 17, 2005 hi to all! this is my first post in this forum, hope that someone will be able to help me. we use the frog in our little cellar theater. it's a great desk and so far everything is great. we have two md players connected to a mixer which we use for all the music/sound effects. no hum with this setup. no i wanted to use the pc which is standing around in the corner for short sound samples because these md players are so damm slow. but as soon as the pc comes into play, we got this huge amount of hum when the frog fires up. i really tried everything i know. first of course i thought of an earth loop. the frog was connected to an tft monitor and the pc keyboard via a monitor switch (the other side of the switch was connected to the pc). as soon as i removed the video connection, the hum got a lot better. but it's still there and not at an acceptable level (the current play is very quiet at times and the hum very irritating). i've even put in a 47 ohm resistance to break a ground loop in the audio connection of the pc. what else can i do? are the special mains filters to connect the frog to? is this a common problem? please help! max Quote Link to comment Share on other sites More sharing options...
Brian Posted October 17, 2005 Report Share Posted October 17, 2005 You've got an earth loop (which I think you knew). You are on the right track with the 47 Ohm resisotr but I think you need to go further. You must break the earth between the PC and the audio system. I'm guessing the outputs from the PC are unbalanced; I'd take them into a balanced input on the mixer, the signal line from the PC into the 'hot, the 'earth' from the PC into the cold, leave the ground of the audio input disconnected. Or, use a DI box to feed the PC into the mixer. Quote ex-Leap Frog Owner, ex-Mambo Frog Owner, ex-XLS Owner, ex-Alcora Owner, ex-Elara Owner Owner of a big pile of Betapack 2s Bozone (n): The substance surrounding stupid people that stops bright ideas from penetrating. "Am I dreaming this?" "No, and you ain't in Kansas neither." "Longbottom's been neglecting his ear muffs." Link to comment Share on other sites More sharing options...
kaufhaus Posted October 17, 2005 Author Report Share Posted October 17, 2005 thanks a lot brian!!!! yes, the outputs are unabalanced. just a cheap card with 3,5mm stereo jack connectors. i gonna try what you suggested asap. Quote Link to comment Share on other sites More sharing options...
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