Using XLR cables for long guitar cable runs

sile2001

sile2001

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I'm trying to find a way to relocate my amp off-stage (like in another room) for my live stuff so I can really crank the amp without interferring with the house sound. The problem is that due to my positioning on stage, these runs could be 40ft long or more. Consider a 40ft run from guitar to amp, 40ft back from effects send to my pedal board, then 40ft back to the effects return, and that's gonna be a fair bit of signal loss.

Would I be able to solve this problem by using direct boxes on both ends so I would have a balanced low-impedance signal making the long runs?
 
sile2001 said:
I'm trying to find a way to relocate my amp off-stage (like in another room) for my live stuff so I can really crank the amp without interferring with the house sound. The problem is that due to my positioning on stage, these runs could be 40ft long or more. Consider a 40ft run from guitar to amp, 40ft back from effects send to my pedal board, then 40ft back to the effects return, and that's gonna be a fair bit of signal loss.

Would I be able to solve this problem by using direct boxes on both ends so I would have a balanced low-impedance signal making the long runs?
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Probably don't need to go that far, equipment-wise. From guitar to amp, there is a thing called a line driver, which will give you a low-impedance line signal, which won't suffer from cable capacitance. Kinda spendy, though. Pete Cornish makes one. Boss used to make a pedal called the Line Driver, you may be able to find one.
Many effects pedals, including the Boss TU2 and GE7, have a low-impedance output, and might work as a front end. In any case, you will probably have to set your amp a bit differently.

If you do go the DI route, realize you will need an active DI for the guitar to amp run. A passive DI won't have enough input impedance, and your tone will probably suffer.

The FX loop will already be low-impedance, most likely, and shouldn't need DI boxes. The manual should tell you. In the FX loop, noise will probably be a bigger problem than loss if it is low-impedance, unless your FX loop is balanced. If not, some noise problems can be cured using DIs and a couple cable mods.
 
You would just be adding even more capcitence, which is the primary problem with long guitar runs. Basically, you would loose a huge amount of high end.


Light

"Cowards can never be moral."
M.K. Gandhi
 
why do you need to crank the amp? Can you just use a power attenuator like a marshall powerbrake or a THD hotplate?
 
sile2001 said:
Well crap.......not exactly sure what to do then. Is there such a thing as an isolation box for an amp?
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Yes, a bunch are out there. I don't think what you want to do is a big deal, but you might need to experiment a bit to make it work. Maybe you can borrow/ rent the cables, etc. for that?

Also, turning your amp towards a wall goes a long way, another thing to experiment with.
 
metalhead28 said:
why do you need to crank the amp? Can you just use a power attenuator like a marshall powerbrake or a THD hotplate?
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I need to crank the amp so I can drive the speaker into a very slight bit of distortion. I've got a Peavey Classic 30 (with JJ Tesla tubes) and replaced the stock 75 watt Peavey Blue Marvel speaker with a 25 watt made-in-england Celestion Greenback. With the old speaker, driving it up to slight speaker distortion was impossible, but with the lower wattage Greenback, it is within range of the amp's power, and damn does it sound good!
 
boingoman said:
That's freakin' high-class cool.
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Yeah, well, Alan Smart is, well, smart.

He makes really great stuff.


Light

"Cowards can never be moral."
M.K. Gandhi
 
A Peavey Classic 30 is too loud ?? man that must really crank, or you have a really small place to play in?

I would think the classic 30 would be perfect for any club. even at moderate cranking levels.

maybe throw a heavy moving pad or blanket over it after you mic it? or get one of those sound proof wall coverings to put over it ??
like this, maybe fold it up to fit your amp ? heck i dont know if it would work, but it is a possibility. alot cheaper than new cords and DI's

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7335222516&category=3278&rd=1
 
The FX send won't be low impedance unless you are using 3 conductor cables and your gear is built to use them, but it will be line level, so you shouldn't have too much loss in that part of the setup. I don't know what pedals you are using, but 9V stomp box units usually work better in front of the amp than in the loop.

My advice is to wire it all up in the same room with you but with the cable lengths you'll need and A/B it with short cables, and see how much of a prob it really is before you go in search of more exotic solutions. You might also try putting your pedals before the amp. I am always in favor of fully investigating whether I can do what I want to do with what I have before I go out and spend money on something that may or may not help me.
 
The FX loop out is around 1kohm, maybe not low impedance compared to a mic, but probably enough to drive 50 feet of cable no problem. 1Kohm is about the same a alot of pedals.

I think output circuitry is more important in determing output impedance than whether it is balanced or not. Many power amps have output impedance way less than one ohm, for instance. Am I wrong?

Sile- that's not a very big amp. The last time I recorded in my living room, I built a box to put over my amp with vents on the back and top. I played an Ampeg Jet at the time. That may not be the right solution for a hot club, though. Amps don't like tons of heat.

You could pull the amp, make a head box for it, and get a Demeter Silent Speaker box, $550 direct from them. Not bad, considering the cost of DIs and cables.

And like I said, it's amazing what firing it at a wall into a blanket or something and using a low-profile mic like a Sennheiser 609 or CAD E-100 will do. Lo-tech isn't always bad.

http://www.demeteramps.com/
 
boingoman said:
The FX loop out is around 1kohm, maybe not low impedance compared to a mic, but probably enough to drive 50 feet of cable no problem. 1Kohm is about the same a alot of pedals.
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Technically correct, but when most folks say low impedance, what they really mean is balanced.
 
metalj said:
A Peavey Classic 30 is too loud ?? man that must really crank, or you have a really small place to play in?

I would think the classic 30 would be perfect for any club. even at moderate cranking levels.
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Have you ever played one of these things? All I can say is DAMN! They don't have the reputation of being the loudest 30 watt amp ever made for nothing... :D . And adding that Greenback (with its higher sensitivity) sure didn't quiet it down at all!

The main problem I'm having is that reflections are causing hot spots in the room. To keep the amp+mains sound from deafening people in some locations, it has to be turned down in the mains to where it is almost inaudible in other parts of the room.

My effects are both before the preamp AND in the effects loop, and for some of the stuff I do, having the delay and secondary EQ before the preamp is not an option. Otherwise, i would be fine with putting it all before the preamp.

I guess I'll just have to play around with the positioning and see if I can get it to fire into something sound absorbent.
 
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