Help on a Behringer Bass V-amp

[DanLights]

I know many people hate Behringer, but I'm not going to discuss that here, I know this thing is nowhere near a real thing or a Pod for that matter, but it's what I got. so...

I tried to use it in a show with my band last month, the bass rig was a SWR head connected to a crown Power amp (sound guy told me the swr's power amp wasn't working or something like that, don't remember) and through a 4x10 cab for monitoring, so I talked to the sound guy about connecting my V-amp and he helped me set it up bypassing the head. Simply bass > bass v-amp > power amp > rest of the show's rig. The problem is it was making noise ("tierra" in spanish, ground noise if translated? not sure) so in the end I didn't use it and ended up using just the house rig. The sound guy said that it doesn't mean the v-amp is damaged or anything (it's friggin brand new), he said it must be a polarity problem, some polarity inverted in relation to the rest of the rig, that I should check that out. I have used it in rehearsals on 2 behringer bass amps and works perfectly.

So the thing is... how on earth do i check/fix that? I understood all the sound guy said, but actually have no idea how to check that, was kinda embarrassed to ask that in middle of sound check. Any ideas? please?

 

[AudioGeekZine]

Were the two devices (V-Amp and Power amp) on different circuits or different outlets?

Were you using a balanced cable between the V-Amp and Power amp?

 

[DanLights]

Were the two devices (V-Amp and Power amp) on different circuits or different outlets?

Yeah, different outlets I´m almost sure

Were you using a balanced cable between the V-Amp and Power amp?

Can´t be sure, the sound guy did that, but I´m almost certain it was not a balanced cable but a normal mono "instrument" cable. It was not XLR that´s for sure, V-amp does not have an XLR output, only the pro version does (which I sadly could not find in my country anywhere)

Please explain how this affects ground noise, appreciated

 

[Jarkko Mattheiszen]

So, the sound guy hooked them up to different outlets and the first thing he suspected was a polarity problem. Yeeeeeah.

If two interconnected pieces of audio equipment are hooked up to two different outlets, it's possible that their ground potentials aren't equal. That results in equalizing current between the two devices, and that equals hum. I'm pretty sure I'm not using the correct words here since I don't know their English counterwords and I'm about to fall asleep on my chair

 

[John_C]

So, the sound guy hooked them up to different outlets and the first thing he suspected was a polarity problem. Yeeeeeah.

If two interconnected pieces of audio equipment are hooked up to two different outlets, it's possible that their ground potentials aren't equal. That results in equalizing current between the two devices, and that equals hum. I'm pretty sure I'm not using the correct words here since I don't know their English counterwords and I'm about to fall asleep on my chair

nope, you got it right

 

[DanLights]

thanks jhakwe, I didn't know that, my knowledge in the whole voltage, impedance thing is somewhere near zero. Any other reasons? I will email behringer's support cause I read in some reviews some people were having noise issues and they responded back with some solutions that proved useful.