Any thoughts on what I can do to fix noise in my signal chain?

TheBigDipper

I did a gig last night and had a technical issue in the soundcheck. Looking for a strategy for next time. 

I often go direct, and that's what we did last night. Signal chain is guitar --> pedals in loops on a Boss ES-5 --> OE RevivalDrive Compact (my "amp") --> Eventide H90 --> Neunaber Iconoclast (my "cab"). It's all mono. The output from the Iconoclast is a balanced TRS socket and I have a balanced TRS-to-XLR cable. 

Totally noiseless at home into a Laney FRFR speaker or a mixer. Totally noiseless at our practice space into a Behringer XR18. 

At the gig, I plugged into a female XLR cable connected to the venues stage box. When the engineer brought me up into the mix, I had noise on my signal. Very similar to a dirty pot being rotated back and forth quite slowly, a hissy sort of whooshing/crackling  noise. We tried a different cable from my board to their female XLR. We tried a different female XLR cable. We tried a different connection in the stage box and a different channel strip on the mixer. Then we bypassed the Iconoclast and went straight from the H90 using my balanced cable into their female XLR. No noise. So that's what we went with - the engineer worked some EQ magic on my channel strip and my sound was fine for the gig. 

So, just now, I've unpacked, reconnected the Iconoclast and retested everything. No noise. 

Help! I don't want the stress of getting this next time and we'll certainly be back at the same venue in a few months. 

What can I do to test that my end is working properly - for instance, that the balanced outputs from the iconoclast really are balanced? What can I do to overcome any problems or incompatibilities with the house PA. Would a DI box help? Our bass player connected into the stage box in the same way, using an Origin Effects BassRig Super Vintage (which has an embedded XLR output) and the drummer gave the engineer 8 balanced outputs from his controller. They were both quiet as mice.... :-( 

Danny1969

That sounds like power supply noise.  My advice get a passive DI box. This just contains a simple transformer and in a lot of cases this will solve a lot of problems. A DI transformer produces a differential output across pins 2 and 3 with no reference to earth. 

I'm not familiar with the Iconoclast but it sound like power supply bourne noise to me rather than noise picked up onroute to the desk. These days with digital stage boxes on stage, and relatively short journeys for unbalanced signals (compared to the 30 metres or so they used to be ) it's  less of an issue but still a good idea to be properly differential balanced. 

The Radial boxes are great for stereo but even Behringer can't fck up a passive DI as it's just a transformer in a box

fretmeister

Did the board have phantom power activated?

TheBigDipper

@Danny1969 Good advice that I'm going to take on board. The venue had several DI boxes nearby but didn't suggest using one. I was more in "pre-gig got a problem" panic mode, so didn't think. 

 @fretmeister You win the prize! Good shout. I just tried connecting the pedalboard with my mixer sending phantom power down the cable and it recreated the problem perfectly. I assume the H90 has some protection against being given phantom power that the Iconoclast does not. 

Thanks, gents! :-) 

fretmeister

A lot of people using modellers or other non-amp rigs fall foul of the phantom power issue.

While it won't hurt many modern modelling units it will make a horrible noise. Doesn't help that some desks either have it on or off for the entire board, or in multiple channels.

Sticking a passive DI box in the way will solve the problem even if the phantom power is on, and will also protect the gear on the off chance it is one that will be harmed by it.

Glad you got it figured out!

ICBM

It's absolutely unbelievable in this day and age that anyone makes anything with an XLR output which won't accept phantom power on the line without causing trouble (or worse, being damaged).

As Danny1969 and fretmeister said, a passive DI will fix it - in my opinion, they also sound better for electric guitar and bass as well, they seem to handle overdriven sounds more 'naturally'.

Cranky

These work great for me.

TheBigDipper

I've ordered a Behringer DI100. I run in mono with the band, and this is only for use if I'm going direct. It has the extra feature of allowing me to use the XLR output for FOH sound but also feed an amp onstage if I need to. The next time someone feeds me unwanted phantom power the DI100 will cut out the battery and use it to power itself ;-)

digitalkettle

TheBigDipper said:

I've ordered a Behringer DI100. I run in mono with the band, and this is only for use if I'm going direct. It has the extra feature of allowing me to use the XLR output for FOH sound but also feed an amp onstage if I need to. The next time someone feeds me unwanted phantom power the DI100 will cut out the battery and use it to power itself ;-)

So you didn’t buy a passive DI? I like not worrying about battery powered devices

TheBigDipper

digitalkettle said:

TheBigDipper said:

I've ordered a Behringer DI100. I run in mono with the band, and this is only for use if I'm going direct. It has the extra feature of allowing me to use the XLR output for FOH sound but also feed an amp onstage if I need to. The next time someone feeds me unwanted phantom power the DI100 will cut out the battery and use it to power itself ;-)

So you didn’t buy a passive DI? I like not worrying about battery powered devices

Well....  I wasn't going to agonise about my choice too much, just make a decision and move on. It's only going to get used when I plug in at unfamiliar places (venues) and our originals band is unlikely to do more than 10-12 gigs a year. I already have a battery-charging routine in place, so an extra one isn't too much of a worry. :-)

shufflebeat

My suggestion would be to buy a passive DI anyway, ART and Orchid would be my go-to with DOD and Whirlwind showing up from time to time on eBay.

There’s not much to go wrong with them and they’ll all sound better than the DT100, which I predict is a thought coming your way before long.