Best way to split a guitar signal?

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?

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.

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

This will get your search started in the right direction.

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!

A nice DI box will typically have a thru output.
Route the DI's XLR for direct recording... and route the DI's 1/4" thru output to the Amp.

"Passive DI's will load your guitars PU down so they suck away a bit of juice/ tone."

Hmmmm. I wonder if this applies to bass guitar as well. I've always used passive DI boxes for live and studio work for passive basses.(until I got an interface with Hi-z input.) I'm getting ready to record 6 string leads in exactly the same way as the OP so this post is good food for thought.

There is a very simple approach. 

Use a good quailty DI and active at that. Make sure the output that feeds the amp is in direct parallel to the input signal and there won't be any degradation. The high input impedance of the DI box will have no effect on the guitar sound back to the amp.

Use phantom power as well where ever you can with a DI. It is worth it.

Mikes approach while good is a bit over complicated. (It also implies you want the sound of a preamp in line to the guitar amp and in many cases it is not required or preferred. Sometimes with guitar the shortest most direct route is the best option. But Mikes approach also shows a bass guitar not a guitar and for bass I could imagine that would be a nice setup)

In most situations you only need a DI and the mic signal in front of the amp.

If a guitarist has got an array of effects pedals before the amp, a good approach is to record three tracks. One straight out of the guitar as mentioned. (First DI) A second track straight out of the effects units but before the amp (using a second DI) and the third the miced amp sound. Sometimes the effects straight out will sound better than the amped sound with the effects.

I have just done a bunch of guitar tracks and I have found if the guitar is plugged direct to the amp and the amp is very clean sounding you don't even need the DI signal from the guitar either. The clean recorded amp sound also works fine with VST's and things.

But the moment the amp sound is distorted (or effected) in any way then the DI signal becomes rather important and useful.

Spend the time getting the amp settings correct and you will be much happier. Check the guitarist is using the best pickup and settings for any given sound. (and part) Often I find they don't always extract the best possible sound and you might have to do it for them. A professional guitarist will let you fiddle the sound if you are not happy. 

Keep the amount of reverb in the amp way down. Guitarists often try to wind up the reverb. It is horrible usually and you are stuck with it forever. You can add in any spring reverb later but also much nicer reverbs too.

If you are doing multiple parts and only have one amp, having several guitars is a fantastic option. Get them to switch guitars. Even better is if they have several amps and several guitars. The approach of changing guitars and amps will have a far greater impact later on in mixing where you might want to separate things a little.

Be wary of using the effects send of any guitar amp. Not good advice. Some amps that have a distortion channels like Marshalls might be sending the distorted signal from there.

The ultimate place to get a total clean sound is direct out of the guitar into a DI. Then you know you have a perfect clean and unaltered sound.

Thanks, lot's of good info in here! My mini cube worked fine.

One important discovery was as opposed to using a line out or fx loop, is that with the DI, or split being placed right after the guitar, I didn't have to work about the pedal that were placed in use.

I never thought about using phantom power on a DI, it really works? I assumed since it takes a 9 volt battery that the 48 volts would not be healthy...   Any input on that, how or why it would work from a theoretical view?  

One can easily get too carried away with all the technicalities of how things work. I say rather than spend your time reading up about power supplies (you need to be acquainted with electronics to fully get the most out of that sort of info and if you are not the you wont really benefit so much) spend your time making recordings instead with DI's and learn how to get the best out of them in terms of where they are used in the signal chain. Much more important. Yes there are some issues for sure with DI's but they are not major in the end. I have used them live and in recording situations for years without any issue and always been happy with the signal that has arrived through a DI box. 

The advantages of an active DI are firstly they are quick and easy to setup. Mostly they are pretty transparent in terms of what they do and because they don't have any controls and level settings and things on them it makes them easier and less prone to mis adjust. A preamp set wrongly is going to be a much worse scenario.

Also remember too (and I don't think Mike is factoring this in so much) is that the clean DI signal that comes directly out of a guitar will most likely be processed pretty hard later on with an array of virtual amp and cabinet simulators so the sound of the original DI signal is going to be well and truly lost by the time it finds its way into your final stereo mix buss.

Is the listener going to say Oooh I don't like that guitar sound because it was recorded through a DI with an inferior power supply? If the guitar part is killer then the listener is going to really enjoy it don't you think. That is where it's at. (Frank Gambale still sounds good through a DI. ANY DI!)

I have got a box too that generates 48V DC from a 12V DC input (1 amp) so there are circuits that can step DC voltages up too. But I agree with Mike in that I am not sure they are doing that inside many DI's though. It is quite a large and heavy unit and is designed for phantom powered devices that are connected to mixers that do not offer phantom power. Use phantom power where ever you can with any DI. It will perform better for sure and also it will never go flat either!

Like I said , most DI boxes will automatically use Phantom power if supplied,,, but make sure the one you are using say's this is OK somewhere first. I think that's a piece of vintage gear right? I mean the company doesn't have a web site. You may not be able to find a user manual. Mine say's it right on the box below the XLR output jack. This would be standard. 

I don't really know the history of the Minicube, A friend gave it to back in the days when we were touring with DAC, early 90's, and it sure does show signs of wear.

MINICUBE

audio envelope systems, Inc.

MC-220 D.I. Box

it has a Norm Input   Amp in  Lo Imp out   all 1/4 inch

and XLR Balanced out    a ground lift push button switch  and push button filter switch  _____
                                                                                                                                                    \

It worked perfectly for me with a new fresh battery, I'll see if I can find out more before I try the phantom

I use several of these both in the studio and live.

Both work well for me......

Behringer DI 100
 
Samson Stereo DI

Also, I will say when I'm having a lot of fun, I run my guitar into my interface, then back out to my FX, then back in - through an amp sim -- and out to my looper, and my roland GR-20 in direct, then out to my looper, then the looper back in... I tend to record the midi for the guitar part to a silent track just to save it. It's raucous fun and I can run the guitar through Amp Sims before sending it to the looper. Look! I'm using all of my inputs for me and my guitar! Aren't I special!!