SVT-CL sending radio out through DI

[melarson]

I was running sound last night for our church worship team at the county fair and ran into a problem with the DI out on his head. I was picking up am radio through the DI out of his Ampeg SVT-CL. I also tried to use the slave out into a separate DI box but it was still the same. No radio was coming from his 8x10 so I think it is in the amp and not guitar or cables. For reference he is using a Stingray through a Boss TU-2 tuner and Monster Cable cables. He plays though a Hartke head at church and we don't have an issue. I've done sound twice when he has used the Ampeg head in 2 locations about 90 miles apart and have had the radio issue both times. Anyone else had this problem?

[coreyfyfe]

Happens fairly often if you have unshielded components/cables. Search for radio and you should come up with 4 or 5 threads with recommendations for how to solve the issue.

[joelb79]

Better cables sure, but sometimes some places just seem to bring out the worst in our gear. The next night, different place things can mysteriously disappear.

My synopsis.. if the ground lift on you DI was not doing it, and the signal was coming through the line out but not your speakers, this is most likely due to a grounding problem with the place you are playing at. I've had it happen before.

[chicago_mike]

I had taxi cabs come thru my Aguilar rig a couple times...ouch.

[melarson]

Originally Posted by coreyfyfe

Happens fairly often if you have unshielded components/cables. Search for radio and you should come up with 4 or 5 threads with recommendations for how to solve the issue.

Yeah, I had to shield my p bass and fix the wiring on a poor pre install on my KZ5 to eliminate radio. They picked up radio and sent it to both the speakers and DI on several different rigs. This only happens when this head is used. I did several searches, then and also today, but didn't find anything relevant to this situation. I don't think it's unshielded cables, he's using Monster Cables. I know there are plenty of people who believe they are over priced and not a good value, but I haven't heard of too many complaints about them being poor cables. Maybe I'm wrong. The thing that is so weird to me is that it is not heard through the cab.

[Jerrold Tiers]

If it does not come through the speaker, then it is not interfering inside the head, and it basically isn't a head problem.

Sounds like a mixer issue....... Could be the mixer has a "pin one problem" or other grounding issue that acts differently with different things out at the end of the wire... or maybe there is not so much radio signal in the "right" (wrong?) bands at the other locations.

[jelwood]

Well if he plays with the same cables through the Hartke and doesn't get it then, well...it's not the cables!

But really, stuff like that is weird. I once plugged my combo amp into an outlet at my grandmother's house and got a nice surprise. Sounded something like "Para bailar la bamba!"

[Jerrold Tiers]

Originally Posted by jelwood

Well if he plays with the same cables through the Hartke and doesn't get it then, well...it's not the cables!

It's usually the piece of equipment that the pickup occurs in.... in this case apparently the mixer, combined with the location.

If another piece doesn't cause the PA to pick up the radio, there is some difference in the two units, but that does not 'finger" one of them as a "cause"...... The actual pickup is in the PA mixer, and the different equipment simply becomes part of the "antenna".

If one has a ground lift and the other does not, that could be part of it..... lots of things affect RF interference, but the bottom line is that the piece that picks up the radio is the one with the problem.

There ARE cases where nearly anything that is not military "Tempest" compliant will pick up radio...... depends where the transmitter is.