After reading Slash's autobiography a few weeks ago I became consumed with figuring out how to best capture Slash's guitar sound. Most people, myself included, have fallen in love with the rich, fat, warm, and full of sustain tone that is instantly recognizable as Slash.
Keep in mind-Slash himself in his book believes that the sound he achieved on the Appetite For Destruction album was a fluke. He was using a handmade amp based off of a Marshall head that was modified with a unique combination off tubes and circuits. At this point, Slash was still using his first electric guitar, a B.C.Rich. After the band finished recording their parts, Slash went back with a Les Paul and that same magical handmade amp and started messing around with different settings. After a few hours, he reports, he told the sound engineer to halt everything and hit the record button. For the next three weeks Slash re-recorded every single guitar part on that album using this setting. Slash himself admits that even he is unable to reproduce that exact tone found on the first Gun's N Roses record.
Slash ended up buying that amp, which was later stolen. He was able to find the same person who crafted the first amp and bought one with similar specs but even that tone was not the same. Listen for yourself to the first Guns record and compare if sonically to the others. The guitar sounds incredible on Appetite.
Now that I've given you a pretty depressing history lesson, you are probably wondering if you will even yourself capture Slash's guitar tone. First step, buy yourself a Gibson guitar fitted with Seymore Duncan brand pickups. While Slash loves Les Pauls, they come fitted
with traditional Humbucker pickups. Slash feels that these produce too jazzy of a tone and opts instead for a warmer rock tone.
Secondly, run your amp through any number of preamps offered by Marshall. This will give you much more control over the sound of the tone. The amp of choice itself should be a JCM 2000. Slash sets his amp to gain of about 75% full. This prevents his sound from becoming too distorted. Again, you are going for a more bluesy tone than anything heavy. Next, just set you tone to a very middle of the road sonically. Less treble and more mid range will help emulate his warm sound. Let the guitar do the rest.
What I love about Slash's playing is that he opts for less notes, more tone, and super melodic bends which defy genres at times blurring rock, blues, and even jazz so perfectly.
With these basic tools you should be on your way to capturing some of Slash's guitar sound. He'll, you could save yourself a lot of time and just buy yourself Guitar Hero III though.