I'm micing up an amp today, but also want a direct signal for the option of using and amp sim as well. I just tried one of my direct boxes by pluging my strat directly into it and connecting the the other input to the amp. I hear a slight reduction in volume and some tonal changes. 
 
Is it this direct box, or my approach?
 
Would a simply y cord be better?
 
Or something completely different?

Which DI box? ,, there can be big differences in the cheaper brands. A Radial for example would not do that. 

A Y cord will change the impedance so is a bad idea. 

Best solution is a Good quality DI box. 

Does your amp have a line out? 

Probably just the DI box. I don't think a Y chord will work the way you want. The split signal needs to be boosted or whatever a DI box does. Is there no trim or other settings on the box? I've heard good things about Sans Amp stuff. I need to figure out something similar myself.

The Di is a DIB-100    I just tried the y cord with one side going to the amp and one to the DI Box, as soon as I plug the end into the DI the signal to the amp changes...

So yes I agree neither  is ideal.

I may try the line out, I know he has one (he'll be here later today) but I was hoping to keep the dI side of the signal totally clean, I mean it couldn't possibly be good to put a distorted signal into and amp sim :)    except for the exceptions of course....

So in a moment I have a minicube active DI  soon as I go get a battery I'll try it.....

just trying to prepare.

How good is he? Can you get him to just double the tracks or is it a lot of lead work?

He's a fabulous guitar player, but it's all going to be improvised on the fly. I'm simply wanting to capture the direct signal for tonal options and all the fun toys that we have available in Guitar Rig and TH2. I have toys, I want to play with them :)

This will get your search started in the right direction.

Well maybe you could rent a good DI box for the day. Also if the first DI box you were trying uses a battery maybe it's running out of juice or if you're using a wall adapter switch to the battery. Sometimes fresh batteries work better than plugging it into the wall. It can definitely make a difference with guitar pedals which is why I always opt for batteries over an adapter. Have fun.

The first one was passive, The second one being active, and now that I have a battery works great! No perceivable change to the real amp. This will work for today.

Spacey, thanks for the link, heading there now!

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