Hello guys, i have a question:
I own a Behringer DI100 DI-Box and my idea was to connect the output of my guitar head (Marshall MA50H 50W) into the DI-Box so that i could get the tone of my amp into a passive mixer. This because I actually can't mic the speaker... Is it possible to be done without causing damages to the amp or the other gear?

So the connections would be:
Guitar->Amplifier->DI-Box->Mixer->Speakers

Thanks to everybody who will help me!

Hi Simone, before someone else with more experience with this type of task chimes in I'd like to ask you to wait with this.
I'm not sure, but I don't think this connection can be done this way and you could damage your gear. Only if your amp head has a DI out on it, then you can connect it to your DI100 or mixer unit. Speaker out output on the amp head requires you to have a "speaker load" and you need to use specially designed DI units for this kind of connection you are looking for.

The safer option might be to take the signal from the effects loop output on the amp.

Hi Bogdan, thanks for the fast reply
I found the manual of the unit there http://www.behringer.com/assets/DI100_P0062_M_en.pdf and at point 2.4 it seems to say something related to that connection I want to do, but I can't honestly understand it totally as it says it can hold 3000 watt power (wow).
On the other hand, with the connection you suggested by taking the signal from the effects loop output i still would have to connect an impedance to the speaker output in order to not damage the amplifier, right?

If you would take the signal from the effects loop, you would also have to connect the guitar cabinet (speaker) to the head the usual way just like if you would be playing regularly. We have some guys in the forum which know these connections inside out, let's wait and see what they say.

I would personally approach the whole thing a bit different though and do it like this :

Guitar>DI>Mixer>Computer Amp/speaker modeling Plug Ins>Computer Speakers

This way you get a dry guitar signal into your computer and shape it using plugins. When using the real amp, the only right way is to mic the cabinet. Otherwise using it just to get slightly colored DI signal often can sound worse then going straight to the computer via guitar>di box. This is of course only my opinion

There are some cool free guitar amp/cab modeling plugins, let me know if you'd like me to send you some links.

There are other brands but these are pretty much the industry standard for what you want.
Do not cheap out on this stuff. You'll burn up your amplifier.

If you can or want to still 'hear' your amp through the speaker you can use one of these ...
http://www.radialeng.com/jdx.php
http://www.zzounds.com/item--HUGREDBOX5?si...aFjZBoCWjfw_wcB
http://www.sweetwater.com/store/detail/Cab...1UjYRoChdrw_wcB

If you want the speaker silent ... http://www.palmer-germany.com/mi/en/PDI-03...-ohms-PDI03.htm
Or, ... http://www.koch-amps.com/lb120-loadbox.html

*The Boogie and the Koch can accomplish both options.

It doesn't look like your unit has any SPEAKER EMULATION which means that even if you route it like your thinking about, it will probably sound a bit awful. Part of your tone comes from your speaker. if your head has an emulated speaker output then you could route that to your DI box then to the mixer. But if you are just trying to run a line out to your mixer the tone will be pretty bad.

As KlASAINE mentioned, there are devices that are built for this type of thing and that have speaker emulation built in so that what goes to your mixer sounds like your amp/cab not like a gritty mess

By using the fx loop, you're missing almost half the character of the amp as the power section is also important for tone. I tried this with my combo amp, its ok but not really good either actually thinking about buying a pedal type amp for recording stuff...

But my amp isn't tube, I've been in an unsettled argument where is tube amps might be damaged cause of using fx loop (the power section of the amp still works and not using it to power the speaker might cause overheat and damage it...or not) so I also can't advise this till I confirm from someone I can fully trust.

But as others said, its really worth investing on a tool to convert the speaker out to line level. I know someone whose really happy with this approach, he opens a cab. sim. on computer and shares a blues jam sometimes 3 times a week if you're thinking live then yeah get one with a speaker emulator.

Your amp seems pretty cool so by investing on the better stuff I'm sure you'll enjoy more .