There was an article in EQ in June 2004. Here's a reprint:
http://www.belowempty.com/vr/articles/2004/040601_EQMagazine.php
here's the parts pertaining to Slash.
Guitars, Guitars, and More Guitars
You can't think of really rockin' guitars and not think of Slash. And you can't think of Slash without thinking of Les Paul, his guitar of choice. For Contraband Abrahams, Williams, and the rest of the guys all agree Slash did some experimenting, but he insists that he didn't stray far from the norm. On the band's debut single, "Slither" he confides that he kept it really simple using a Les Paul and a Marshall all the way through. "I did use a delay in the beginning of the song for that 'swallow' effect but that one was a pretty simple Slash set up." he says.
When pressed, he admits to changing things up a bit here and there. " I experimented with a couple of different amps for different sounds. I used a couple of different pedals for certain parts of songs, and I used more than just my one Les Paul. I used a couple different guitars. On 'Falling To Pieces' I used a Gibson 335 through an old Fender mixed with a Vox for a clean sound. I found that I was really a lot more open-minded about each song as opposed to the way I used to do it in the old days, which was just get one basic sound and use it throughout," shares Slash. "That is sort of my live approach, but these songs really demanded a little bit of a more creative approach technically. It was a lot of fun to do it. Also, at this point I would've felt really stale just sticking with the one formula" For the secrets behind Slash's set up we turned to Ryan Williams.
Set Up Secrets
Williams, a guitarist himself, says Slash's set up varied, but never strayed too far from the Les Paul/Marshall combination. For the track "Falling to Pieces" he ran two Marshall heads: one Slash's signature model and the other a JCM800. Williams continues, "We also managed to use a Vox AC30 in the chain as well, which I don't think he's really used before. It's kind of a matter of mixing all the different amps to come up with one good tone. Each of them plays their own little part in creating the tone. I think he kind of digs that. Most of the tracks we started with that and then went from there."
Williams recalls that the amps were miked with Shure SM57's because Slash likes "a nice, bright tone with a lot of presence" Williams ran the mics through Neve 1073s and mixed them together into one track. "I don't like complicated things all spread out on different tracks. Mix all those amps down to one track to create one sound that goes through a Pultec for a little more EQ and that's it," he concludes.
When miking the amps Williams positioned the mics very close to the cabinets and a little off-center, making sure all the mics were the same distance from each speaker. "I just try to eyeball it and make sure the mics are the same distance from all of the speakers, because if you mix a couple of different amps, then there's always phasing issues. So, just to keep the mics an inch off the grille cloth on all the cabinets that I'm miking helps me keep the phase in check."
Williams relies on experience and technique, but reveals the greatest tools are common sense and a great pair of ears. " Of course Slash is an amazing guitar player, and Dave as well, so I just make sure it's the right guitar, it's the right amp, and make sure it sounds good standing in the room. I always stand in the room and listen to what's coming out of the speakers first. I make sure that's right before I start reaching for a ton of knobs to try and fix things. If it is sounding good coming out of the cabinet then there is no reason you shouldn't be able to throw a mic on it and go."