loud hum from my rack when using di boxes??

PLAYSTEEL9 · Post by **PLAYSTEEL9** » 12 Mar 2001 5:53 pm

i am getting a loud hum from one side only of my profex11 when i put a di between the amp and the profex11, it's louder the closer the box gets to the power supply, with just stright patch cords, no di, i don't have the hum???
i just play em, don't understand em.
any help for a fellow picker/
wayne
maybe if it knew the words it wouldn't hum!!!

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Those that make music, pray twice.

Matt Farrow · Post by **Matt Farrow** » 13 Mar 2001 5:33 am

Wayne, a DI box is usually nothing more than a transformer that your guitar is connected to, to change the impedance of your signal to make it more suitable for use with studio electronics. A transformer is a coil of wire wrapped around a core of some magnetic material, which is a lot like a guitar pickup. So the transformer in your DI box is picking up the stray electromagnetic fields from your Profex. Put the DI on the floor or away from your Profex, or use the line out of your amp or Profex instead.

Matt Farrow
Pharaoh Amplifiers

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Matt Farrow
Marlen 9-string 6+2
Kustom K150

http://surf.to/pharaohamps

Jack Stoner · Post by **Jack Stoner** » 13 Mar 2001 5:38 am

There is no need for a DI box between the Profex II and a power amp. It is made to drive a power amp. What/Why are you using the DI box??

Craig A Davidson · Post by **Craig A Davidson** » 13 Mar 2001 7:02 am

Jack, I would bet that Wayne is running a line to the board. Therefore he would have a DI between the guitar and amp. They do that in these modern times in place of miking it. It will hum if it is near a power source. Placing it on top of an amp will do the same thing.Try to put it on the floor away from your pro-fex as suggested. That will probably cure it. Something I was taught long ago was to get in the habit of running all audio cables away from power source cables. If you run an audio cable by an extension cord it can pick up the current going thru and create noise in your audio. Didn't believe it till it happened to me once. If you are used to running a DI that's ok but miking your amp will give you a truer image of what your guitar actually sounds like,because you are getting the sound of your speaker also.

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Olli Haavisto · Post by **Olli Haavisto** » 13 Mar 2001 12:14 pm

Try a DI box with a ground lift function;sounds like groundloop problem to me

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Olli Haavisto
Polar steeler
Finland