Electrical Disto Evaluation and Upgrade Options

C

Chris Delcambre

Freshman
Mar 11, 2013
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This past weekend I had my first show with my new sound and LED lighting system. I was running off of a 56KW generator and was having what I would call some voltage drop issues (LCD's would dim on Crown XTI4000 amplifiers when low sub notes would hit) and I have NEVER had these issues with my previous, smaller setup using exact same distro.


I need a review of my current distro and what wire/distro you would recommend for future upgrades.




Main Distro
1- 125A 6 Space 12 circuit 120/240 Panel.
8- 20A 120V Circuits ran with 12/3 (Edisons)
2- 30A 240V Circuits ran with 10/4 (Twist Locks)
75ft- 6/4 Feeder


Amp Racks
2- Racks with Ampshop Rack Packs
2- Misc racks with 2 quads per rack (4 total circuits)
50ft- 10/4 Feeder from Main Distro
25ft- 10/4 Feeder from Main Distro




Overall I was running the system pretty hard but not getting the response I wanted out of the subs. For the total audio system I was running 4 of the 20A Circuits for 2 Amp Racks and the 2 30A Circuits for 2 other amp racks through the rack packs.

Here is what are in the racks.

Rack : Powered off of the 30A Circuit
Furman
Crest 5200 (Horns) Stereo at 2 ohms
Crest 9200 (Mids) Stereo at 2 ohms
Crest 9200 (Subs) Stereo at 2 ohms
Rack Pack

Rack 2: Powered off of the 30A Circuit
Furman
Crest 5200 (Horns) Stereo at 2 ohms
Crest 9200 (Mids) Stereo at 2 ohms
Crest 9200 (Subs) Stereo at 2 ohms
Rack Pack

Rack 3: Powered off of 1 20A Circuit over 12/3 Ext Cord
Furman
Crown XTI 4000 (Monitor) Stereo at 8 ohms
Crown XTI 4000 (Monitor) Stereo at 8 ohms
Crown XTI 4000 (Monitor) Stereo at 8 ohms
Crown XTI 4000 (Monitor)Stereo at 8 ohms

Rack 4: Powered off of 2 20A Circuits over 2 12/3 Ext Cords
Furman
Crown XTI 4000 (Aux fed Sub) Bridged at 4 ohms
Crown XTI 4000 (Aux fed Sub) Bridged at 4 ohms
Crown XTI 4000 (Aux fed Sub) Bridged at 4 ohms
Crown XTI 4000 (Aux fed Sub) Bridged at 4 ohms


Any suggestions you had would be appreciated.
 
Re: Electrical Disto Evaluation and Upgrade Options

Chris Delcambre said:
This past weekend I had my first show with my new sound and LED lighting system. I was running off of a 56KW generator and was having what I would call some voltage drop issues (LCD's would dim on Crown XTI4000 amplifiers when low sub notes would hit) and I have NEVER had these issues with my previous, smaller setup using exact same distro.
Click to expand...

On the same generator also? If not, it sounds like typical generator sagging.
 
Re: Electrical Disto Evaluation and Upgrade Options

What program material were you playing (DJ material, or live band)

A quick comment, your main feeder is undersized, especially if it's bundled or cabtire ... # 6 is good for what maybe 50 amps bundled, and your main is 125... tsk tsk.
Depending on your location, shortly your 10/4 will be undersized on 30 amps...it's heading to #8

Can we safely assume, backline and the lighting rig was running off the geny, or was that being pulled from something else...?

I'm not an electrician, or expert, but these are my observations on your rig. I'd try to lose the 2 ohm load across your amp racks.
 
Re: Electrical Disto Evaluation and Upgrade Options

Shane Presley said:
What program material were you playing (DJ material, or live band)

A quick comment, your main feeder is undersized, especially if it's bundled or cabtire ... # 6 is good for what maybe 50 amps bundled, and your main is 125... tsk tsk.
Depending on your location, shortly your 10/4 will be undersized on 30 amps...it's heading to #8

Can we safely assume, backline and the lighting rig was running off the geny, or was that being pulled from something else...?

I'm not an electrician, or expert, but these are my observations on your rig. I'd try to lose the 2 ohm load across your amp racks.
Click to expand...

That is kind of what I was thinking also. This is what an electrician had spec'd and built me when I told him what I was doing. However it was before I upgraded my rig to have the 2 additional racks.
The backline and LED light power was also run off this distro on the other 4 20A circuits.

I am eventually upgrading to 4 ITech 8000 to get rid of the Bridged 4 ohm amplifiers and the 2 Crest 9200s on subs. My subs are JBL SRX728 so I could use the additional power anyways.

What size wire would you recommend for distro feeder???
 
Re: Electrical Disto Evaluation and Upgrade Options

Chris Delcambre said:
This is what an electrician had spec'd and built me when I told him what I was doing.
The backline and LED light power was also run off this distro on the other 4 20A circuits.
What size wire would you recommend for distro feeder???
Click to expand...

Your electrician was incorrect to quote you #6 on a 125 amp breaker...
To be safe , go with a #2 PPC (portable power cable) entertainment lighting grade feeder cable, that will get you to up to 180 amps
You can go with 2 hot runs (black and red), and a neutral at #2 gauge and drop down to as small as #4 for your ground if you want to save some coin...
it's pretty much standard in the entertainment realm (around here), get 1, or 2 ott if you want to cover 225 amps.
 
Re: Electrical Disto Evaluation and Upgrade Options

Shane Presley said:
What program material were you playing (DJ material, or live band)

A quick comment, your main feeder is undersized, especially if it's bundled or cabtire ... # 6 is good for what maybe 50 amps bundled, and your main is 125... tsk tsk.
Depending on your location, shortly your 10/4 will be undersized on 30 amps...it's heading to #8

Can we safely assume, backline and the lighting rig was running off the geny, or was that being pulled from something else...?

I'm not an electrician, or expert, but these are my observations on your rig. I'd try to lose the 2 ohm load across your amp racks.
Click to expand...

I'm with Presley, your feeder is undersized. You should be using #2AWG type SC or equal.

And I'm with Hamilton, I think the genset is sagging. When you can tell us more about the program material we can speculate some more. ;)

Final comment: The XTi4000 didn't get much love from forum participants when used on subs and they don't like low voltage. If the displays were dimming I'd say you were a couple of volts from shutdown. This is a genset issue.

So, band or DJ/EDM?
 
Re: Electrical Disto Evaluation and Upgrade Options

Tim McCulloch said:
I'm with Presley, your feeder is undersized. You should be using #2AWG type SC or equal.

And I'm with Hamilton, I think the genset is sagging. When you can tell us more about the program material we can speculate some more. ;)

Final comment: The XTi4000 didn't get much love from forum participants when used on subs and they don't like low voltage. If the displays were dimming I'd say you were a couple of volts from shutdown. This is a genset issue.

So, band or DJ/EDM?
Click to expand...

it was both... dj music was countrymusic though and was rolled off on console at 30hz... no dub step or edm...
 
Re: Electrical Disto Evaluation and Upgrade Options

Tim McCulloch said:
I'm with Presley, your feeder is undersized. You should be using #2AWG type SC or equal.

And I'm with Hamilton, I think the genset is sagging. When you can tell us more about the program material we can speculate some more. ;)

Final comment: The XTi4000 didn't get much love from forum participants when used on subs and they don't like low voltage. If the displays were dimming I'd say you were a couple of volts from shutdown. This is a genset issue.

So, band or DJ/EDM?
Click to expand...
The OP said he used Crest 9200 on subs driven Stereo at 2 ohms.

A single Crest 9200 loaded at 2 ohm stereo draws well over 60 amps peak.

Ignoring all the other 2 ohm load PA amps and 8) XTi4000 on monitors and LED lights, the 75 feet of 6/4 would drop 7.2 volts (at only 60 amps) and the 50 feet of 10/4 another 4.3 volts, leaving only 108.5 volts even if the generator held a stiff 120 volts.

Considering all the other loads, it is likely that voltage at the amp racks would have dropped below 105 on peaks, and the amp's output would be some 6 dB (or worse) less than if big cable was used.

Chris could have determined voltage drop by measuring at the genset and at the amp rack, but to me it looks like the undersized (for voltage drop) cable is the culprit.
 
Re: Electrical Disto Evaluation and Upgrade Options

Art Welter said:
The OP said he used Crest 9200 on subs driven Stereo at 2 ohms.

A single Crest 9200 loaded at 2 ohm stereo draws well over 60 amps peak.

Ignoring all the other 2 ohm load PA amps and 8) XTi4000 on monitors and LED lights, the 75 feet of 6/4 would drop 7.2 volts (at only 60 amps) and the 50 feet of 10/4 another 4.3 volts, leaving only 108.5 volts even if the generator held a stiff 120 volts.

Considering all the other loads, it is likely that voltage at the amp racks would have dropped below 105 on peaks, and the amp's output would be some 6 dB (or worse) less than if big cable was used.

Chris could have determined voltage drop by measuring at the genset and at the amp rack, but to me it looks like the undersized (for voltage drop) cable is the culprit.
Click to expand...

Thank You Art. I just spoke with a local electrician and he told me the same thing. The wire was too long to be that small and pulling that size of a load. Fixing to look into upgrading the wiring to 2/4 to resolve this problem. I appreciate everyone elses input also.

Chris
 
Re: Electrical Disto Evaluation and Upgrade Options

Chris Delcambre said:
Thank You Art. I just spoke with a local electrician and he told me the same thing. The wire was too long to be that small and pulling that size of a load. Fixing to look into upgrading the wiring to 2/4 to resolve this problem. I appreciate everyone elses input also.

Chris
Click to expand...

Why 2/4 instead of single conductor SC? 2/4 is only good to 80 amps. Assuming you're using cams or lugs, single conductor SC is the way to go.
 
Re: Electrical Disto Evaluation and Upgrade Options

I PM'd chris... This is what you should be looking for - if you want the rating to be "accurate" for the gauge of cable, you can't electrical tape them together ( like the photo). Thats what they (inspectors) called bundled, and you lose some rating on the cable.

But if you were using #2, your rating is about 180 amps, so bundling on a 125 amp breaker, you'd be ok.
 

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Re: Electrical Disto Evaluation and Upgrade Options

Chris Delcambre said:
This past weekend I had my first show with my new sound and LED lighting system. I was running off of a 56KW generator and was having what I would call some voltage drop issues (LCD's would dim on Crown XTI4000 amplifiers when low sub notes would hit) and I have NEVER had these issues with my previous, smaller setup using exact same distro.


I need a review of my current distro and what wire/distro you would recommend for future upgrades.




Main Distro
1- 125A 6 Space 12 circuit 120/240 Panel.
8- 20A 120V Circuits ran with 12/3 (Edisons)
2- 30A 240V Circuits ran with 10/4 (Twist Locks)
75ft- 6/4 Feeder


Amp Racks
2- Racks with Ampshop Rack Packs
2- Misc racks with 2 quads per rack (4 total circuits)
50ft- 10/4 Feeder from Main Distro
25ft- 10/4 Feeder from Main Distro




Overall I was running the system pretty hard but not getting the response I wanted out of the subs. For the total audio system I was running 4 of the 20A Circuits for 2 Amp Racks and the 2 30A Circuits for 2 other amp racks through the rack packs.

Here is what are in the racks.

Rack : Powered off of the 30A Circuit
Furman
Crest 5200 (Horns) Stereo at 2 ohms
Crest 9200 (Mids) Stereo at 2 ohms
Crest 9200 (Subs) Stereo at 2 ohms
Rack Pack

Rack 2: Powered off of the 30A Circuit
Furman
Crest 5200 (Horns) Stereo at 2 ohms
Crest 9200 (Mids) Stereo at 2 ohms
Crest 9200 (Subs) Stereo at 2 ohms
Rack Pack

Rack 3: Powered off of 1 20A Circuit over 12/3 Ext Cord
Furman
Crown XTI 4000 (Monitor) Stereo at 8 ohms
Crown XTI 4000 (Monitor) Stereo at 8 ohms
Crown XTI 4000 (Monitor) Stereo at 8 ohms
Crown XTI 4000 (Monitor)Stereo at 8 ohms

Rack 4: Powered off of 2 20A Circuits over 2 12/3 Ext Cords
Furman
Crown XTI 4000 (Aux fed Sub) Bridged at 4 ohms
Crown XTI 4000 (Aux fed Sub) Bridged at 4 ohms
Crown XTI 4000 (Aux fed Sub) Bridged at 4 ohms
Crown XTI 4000 (Aux fed Sub) Bridged at 4 ohms


Any suggestions you had would be appreciated.
Click to expand...

Are your "subs" and "aux fed subs" the same? Or operating in a different bandpass? Regardless, that's a lot of PA to run on #6 wire.
 
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