Electrical cabling question for stage setup

[TomB]

I always try for lights on one circuit and audio on another. With modern LED though, probably it's just my habit from the old days... One thing I do in my lighting rig. No signal cable on the floor. Wireless dmx to the tree with all the tree's fixtures locally hard wired. That may help,with noise. It sure makes the setup and tear down faster.

It’s true. Back in the days of PAR lighting, the load was clean but it could draw tons of juice. A separate circuit was advisable to avoid overload. LED has changed that to a relatively small load. Still, control systems can introduce artifacts, both then and now.

 

[Mojo34]

Thank you all for you insights and experience! I'm in charge of laying cables, so I'll watch out for parallels, crossings, isolation (of LED from audio circuits). I may even try a battery powered Preamp/DI.
I have been wondering why people in these forums are running pedals like the Anagram on a battery source... is this why? To isolate from unresolvable electrical problems?
In any case, our big gig is tonight and we do have a sound guy to help with troubleshooting.

 

[TomB]

Thank you all for you insights and experience! I'm in charge of laying cables, so I'll watch out for parallels, crossings, isolation (of LED from audio circuits). I may even try a battery powered Preamp/DI.
I have been wondering why people in these forums are running pedals like the Anagram on a battery source... is this why? To isolate from unresolvable electrical problems?
In any case, our big gig is tonight and we do have a sound guy to help with troubleshooting.

Lately I’ve seen some FB ads for whole-gig batteries - small stages, of course. Portable power packs are growing in popularity. I wonder how they work for a 3-hour gig? That’s another thread, I guess. Good luck with your noise!

 

[Bob_Ross]

So my question is this: IS IT COMMON KNOWLEDGE THAT YOU HAVE TO RUN LIGHTS ON A DIFFERENT CIRCUIT FROM INSTRUMENTS?

Oh hellz yeah.

 

[klyph]

Thank you all for you insights and experience! I'm in charge of laying cables, so I'll watch out for parallels, crossings, isolation (of LED from audio circuits). I may even try a battery powered Preamp/DI.
I have been wondering why people in these forums are running pedals like the Anagram on a battery source... is this why? To isolate from unresolvable electrical problems?
In any case, our big gig is tonight and we do have a sound guy to help with troubleshooting.

Nice. I think batteries probably are the way to go, but in cramped quarters, especially with single coil pickups, you can literally pick up noise from proximity to any sort of power supply/control. I had to play a theatrical show for three months standing next to a light tree with a single coil equipped bass and the only thing that allowed me to do it was a EHX HumDebugger, which is both very effective AND a really terrible pedal. I was using an active DI plugged into house power and I might have had a better time running off a battery. The one rehearsal I did with an active, humbucker equipped bass, there was no noise (but the light tree was off, I think). When the director saw my old beat up bass, he insisted that I use it- that meant using the HDB, and giving up on my Bb.

 

[TomB]

Nice. I think batteries probably are the way to go, but in cramped quarters, especially with single coil pickups, you can literally pick up noise from proximity to any sort of power supply/control. I had to play a theatrical show for three months standing next to a light tree with a single coil equipped bass and the only thing that allowed me to do it was a EHX HumDebugger, which is both very effective AND a really terrible pedal. I was using an active DI plugged into house power and I might have had a better time running off a battery. The one rehearsal I did with an active, humbucker equipped bass, there was no noise (but the light tree was off, I think). When the director saw my old beat up bass, he insisted that I use it- that meant using the HDB, and giving up on my Bb.

What’s an HDB and a Bb? Give up B flat?

 

[klyph]

What’s an HDB and a Bb? Give up B flat?

There was (in addition to other noise) some 60 cycle hum in my signal. The HumDeBugger is a digital automatic noise canceling device, “sensing” unwanted noise and generating an out of phase signal to “cancel” it.

Guess which note is closest to 60 Hz, and suffers “collateral damage” when the HDB cancels 60 cycle hum? Bb. I was able to achieve dead silence when not playing, which was great, but for the two songs in Bb in the show, the root came mostly from the piano. You could hear the attack of the bass, but the fundamental was digitally canceled, which was really weird. Nobody else noticed, so I didn’t care, but I would try many other things to alleviate noise before using that device on bass again.

 

[TomB]

There was (in addition to other noise) some 60 cycle hum in my signal. The HumDeBugger is a digital automatic noise canceling device, “sensing” unwanted noise and generating an out of phase signal to “cancel” it.

Guess which note is closest to 60 Hz, and suffers “collateral damage” when the HDB cancels 60 cycle hum? Bb. I was able to achieve dead silence when not playing, which was great, but for the two songs in Bb in the show, the root came mostly from the piano. You could hear the attack of the bass, but the fundamental was digitally canceled, which was really weird. Nobody else noticed, so I didn’t care, but I would try many other things to alleviate noise before using that device on bass again.

Wow, pick your poison, eh? Thanks for the explanation.

 

[Tommy Sparks]

Most US panels are split phase (different than 2 phase, which doesn’t exist), though many many years ago, there were 2 phase motors running on 3 phase systems.

Two phase is still in use in Philadelphia and still supplied by the utility.
It’s a two phase 5 wire system.
I recently installed a two phase to three phase converter for much easier available three phase motors.

 

[Slevage]

Two phase is still in use in Philadelphia and still supplied by the utility.
It’s a two phase 5 wire system.
I recently installed a two phase to three phase converter for much easier available three phase motors.

Sound like the 2 phase stuff that was used in elevators in Connecticut cities many moons ago. Our instructors who worked on them would be over 100 years old if they were still alive.
Local utility no longer offers 2 phase service and the major drive/servo packages are easily configurable for any common building service.

 

[Mojo34]

Just to add a post-gig comment :

1. I set up lights on a different extension cable from the amps and PA, and didn't have any problem. The cables were plugged into a sort of industrial terminal, so perhaps they were truly separate, I have no way to know. I had no noise.
2. The guitarist's noise was unbearable! But he's got a recurring "unresolvable" pedalboard issue. It was really annoying in my in-ears.
3. My beautiful pedal board (with Genzler Magellan and Two Notes Cab M+) sounded like crap with my wireless in-ears. I told that to the sound engineer (who was awesome) and he fired back at me "you are hearing what you are sending, and it sounds like crap!" I swapped the board for my trusty Acoustic FlyRig and had instantly perfect sound. I can get all the sounds I need for an evening of cover tunes with that pedal. I must be doing something wrong on the big board, but that's a discussion for another day!
4. We had 50-100 people dancing during the entire show, people walking by giving us a thumbs-up, which means we played decently and had an acceptable song list!

Thanks for all your comments.

 

[Wood and Wire]

Hi -

I ran into a problem a stage setup problem the other day with my band: I had electrical hum that I couldn't get rid of!

My usual pedalboard does not make noise, at least none that I hear at home or in practice. The usual "ground-lift" button tricks were not working at all, cables all plugged in, and no loose ends. The last pedal in the chain is a Two Notes Cab M+. I didn't have a ton of time to troubleshoot, so I tried XLS from the Genzler Maggelan preamp and I didn't have the buzz. But the sound without the Cab simulation was not what I wanted, so I plugged in my trusty Tech 21 Acoustic FlyRig and played my heart out with no buzz.

Oh, didn't you know?

All of the cool kids are using Impulse Responses taken from the best speakers, mic'd in rooms with the worst mains hum, to make their cab sims sound like the authentically live experience.