Double Bass euphonic audio iamp picking up radio???

[Kevinlee]

I have a iamp 600 which sounds GREAT, but from time to time I pick up a radio station. It's only when a cable is pluged in to the input. And it happens even when the instrument is not pluged into the other end of the cable. So I'm guessing the cable is acting as an antenna. I use good quality cables, and it's more apperant when I have the power cranked up. I like to turn up the power section and keep the preamp section low.
It lessons if I cut the higher frequencies, and it does not do it all the time. But I'd rather it not happen at all.
Any ideas how to remedy this interferance?

Thanks
Kevinlee

 

[davegr8house]

Hey Kevin,
This was talked about some time ago. I had a Amp that would pick up a Radio Station in St. Louis once, hundreds of miles away. Come to find out it was my cable. Try a "good" cable and see if it gos away. In cables you get what you pay for.

Dave

 

[Kevinlee]

Well the cables I use are good, a.i. there not cheap generic cables. I can't remember what brand they are. However there not new, I suppose a new cable is a good place to start. Suggestions as to what brand? Monster cable? Something else?

Kevinlee

 

[mje]

Even a lot of expensive cables cables have only 80% shield, and even a 100% shield wouldn't work if you were very close to a strong transmitter. (An engineer friend told me he had calculated the shielding of a 1/4" thick brass box and was surprised that a lot of signal could still leak through)

If you regularly have to work in high-RF areas, there's a few simple mods you can do to reduce RF (radio frequency) pickup by your amp. Number one is to slip some ferrite beads over the wires connecting the input jacks to the PC board- assuming the jacks aren't mounted directly to the board. A good tech could do this quickly.

But there are other RF paths into the amp- including the speaker wires and the power cord. You might first try buying a clamp-on RF choke at Radio Shack (about $5) and running your amps's power cord through it.