how to connect guitar amp to PA/soundboard?

[Jason1234]

I have a Fishman Loudbox Performer. On the back of it, for both channels, are XLR ports defined as "D.I. Out (Pre)". Is that what I use to go to the sound board for live music? The manual states "Use this output when you want a flat D.I. signal (whatever that is) to go to the board". It also mentions that you leave it to the soundperson to dial up your tone and effects from the console. That confuses me. I want to use my own effects since I have an effects processor.

There are also effects return and send ports, but I have my effects between my guitar and the port on the front.

Can someone clear this up for me or send me a link to a good site that explains how all this works?

[lschwart]

To answer your first set of questions: you can decide with this amp just what signal you send to the mixing board. If you want to send the final, mixed signal from both channels, including the EQ settings on the amp, whatever internal effects you use, and whatever effects you put into the channel effects loops, you use the XLR out marked "Mix D.I. (post)." If you want to send just the signal from one channel without the EQ, onboard effects, or the stuff in the effects loop, you use the "D.I. Out (pre)" for that channel.

Of course, if you use an effects processor before the amp, those effects will be sent through both the post and pre D.I. outs. If you were to put your effects processor in one of the channel effects loops, the effects would be sent only out through the "Mix D.I. (post)" output (and of course through the amp's own speaker).

The purpose of a D.I. out is to allow you to send a version of your amp's signal--before it gets to the amp's own internal power amp and speaker--to the PA over a balanced, low impedance, XLR cord. This allows the signal to travel relatively long distances without interference or degradation to the XLR input on a channel of a PA mixer. And it allows you to adjust the volume of the amp in a way that's appropriate to your stage situation without changing the level of the signal going to the PA.

After your D.I. out signal gets to the mixer it goes through a preamp on the mixer, to an EQ section and perhaps also through a set of effects used by the house system. It's then sent to a power amp (or more than one) and out through the main and monitor speakers (often the monitor system has its own separate processing and amp or amps).

Which of the various choices you go for with your amp's D.I. outs will depend on what you're trying to accomplish and what your sound man needs from you. Sometimes they're OK with a signal that has already been EQ'd and to which effects have been added. Sometimes they want nothing but a direct signal from your pickup or the preamp you're using, whether it's in the guitar's pickup system, external to it (like in a little box on the floor or on your belt), or in your stage amp, and they prefer to apply EQ and effects at the board.

Hope that helps.

Louis

[sonicland]

Louis provides an excellent answer to your question. It's great to see the first response be explained so well. Nicely done.

[Jason1234]

Louis, I can't thank you enough for spending your time sharing your knowledge. That certainly answers all my questions..and then some!

[lschwart]

You're welcome!

Louis