Had trouble with D&B C4 rig hire co.

[BigYinUK]

Hi all

 

We hired some D&B C4 for a show couple of weeks ago and had some issues with it.

 

We had 4 x C4 subs and 4 x C4 tops plus amps & controllers arranged in two stacks. As always, we did some white noise tests and played some known tracks through it to have a listen pre soundcheck.

 

Our engineer immediately noticed a random crackling (very strange noise) noise coming from one of the tops on the left hand stack. We rang the hire co and they suggested swapping leads and re-seating stuff etc, which we'd already done. Anyway we swapped everything around again and the crackling noise stayed with the same top.

 

Pretty certain that it was the one top that had a fault, our engineer disconnected it and everything seemed fine until later on in the soundcheck when he noticed another noise, more like a very harsh mid, coming from one of the tops on the other stack this time. So, we disconnected that one as well. Now down to 2 subs and 1 top per side. That was no real problem as we're not loud and there was plenty of volume for the show.

 

The rest of the soundcheck and the show ran with no problems.

 

We rang the hire co the next morning and they said they'd check the system over and give us a partial refund as we weren't able to use all the kit we'd hired.

 

This of course is where the trouble started as they are now saying they can't find anything wrong with any of the kit and it "must have been our leads or our desk" so won't issue any refund.

 

I can't see how if it was our kit the trouble would have disappeared when we removed the top(s) from the system, plus we swapped all the cables about so the fault would have moved if it was a duff cable. The desk (and cables) we've used several times since without issue.

 

Any comments advice (other than don't use XXYYZZ again!).

 

Regards

 

Jon

[TonyMitchell]

how many D12s or P1200s were you using to power the C4 stacks?

 

were both of the C4-TOPs with faults common to one channel of amplification?

 

if "yes" to above, did you swap out "bad" for "good" C4-TOPs on same channel?

 

 

 

[BigYinUK]

how many D12s or P1200s were you using to power the C4 stacks?

 

were both of the C4-TOPs with faults common to one channel of amplification?

 

if "yes" to above, did you swap out "bad" for "good" C4-TOPs on same channel?

 

I can part answer that.

 

Don't (myself) fully understand the in's and out's of D&B's amp/controller topology. BUT, I can tell you that there was one daisy chained cable per side (per stack).

 

AFAIA the two "faulty" tops were on separate channels of amplification. We swapped the amps v. stacks over to confirm that it wasn't the amps/controllers that were faulty.

 

We also swapped out cabling each side in case we had a faulty speaker cable (weird D&B multi pin things).

 

Regards