BC780XLT audio hum

[musicman]

When I tried to use the 780 as a wireless microphone receiver, I could not get rid of the hum when I patched it into a portable p.a. system. The hum persisted even through a high-Z to low-Z transformer and a direct box, and it did not matter whether I used the tape jack or the speaker jack. The sound from the 780 speaker was clear and hum-free. Any ideas?

 

[WileECoyote]

What type of portable PA are you using.

 

[mciupa]

Any ideas?

AC hum will mean faulty grounding.

 

[musicman]

780 Hum

2 separate portable PA mixer amps, a Carvin and another brand. Hum pick up on both of them.

 

[n4yek]

Could try grounding the chassis of the 780 to the Mixer. There might
be a differance in ground potential there.

Also you might have a 'ground loop' which can be a bit hard to
find. If this is the case you could try to remove the ground from
the patch cord between the 780 and the mixer.

Just some thoughts to try.

Danny
N4YEK

 

[LordJ]

Might try this..

http://www.radioshack.com/product.asp?catalog_name=CTLG&product_id=270-054

This is what I use to get rid of the Hum when the 780 is connected to my computer. Works great.

 

[musicman]

Thanks!

Since my 780-to-P.A. troubles, I have run into a separate ground loop hum problem at home. This Radio Shack adapter looks like just what I need. Thanks for the tip!