Alexi's sound doesnt come from any cheap distortion pedal.
His old (better) setup:
He uses 2 custom jacksons (a white pinstriped and with the famous yellow bevels). These guitars are equipped with a single J50BC passive humbucker in the bridge. It sort of is a ceramic PAF humbucker with a lower ouput: 8,4 kOhm. J50 B = Bridge and C = Ceramic.
Another thing is the JE1000 gainbooster. The J50BC and the JE1000 are designed to go along with each other.
The JE1000 is a gainbooster with added tone control options (low,mids,high). The ammount of added boost is unknown for me.
Then you have his rack with basicly is:
Lee jackson perfect connectoin GP1000
Rocktron Intellifex
A poweramp ( E640 poweramp, Peavey 50/50).
The pre-amp is very importament for his sound. It is not a high-gain amplifier like all ENGL's/Mesa boogies are today but a true 80's heavy metal amplifier.
Alexi drives his tube amplifier with his J50BC + JE1000 setup and that makes his sound.
He used many poweramps, but any (tube) poweramp will do fine. He used (for example): E840 or E850 poweramp (during sinergy), Peavey 50/50 (old days), Lee jackson SP1000 and many more.
If you dont know what a pre/power amp or a pickup/gainbooster is: google it.
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His modern setup is different.
When his custom ESP's came out in 2003, he uses a passive EMG HZ4 together with a MM04 or JE1000 gainboost. The MM04 is a straight rip off of the JE1000 and is sold in some stores for way to much money. His rack is almost the same as in the old days but he added a TECH21 Sansamp PSA1.1 pre amp. And he uses a VHT 2/90/2 poweramp.
During the summer of 2007 he changed pickup's. He ditched the HZ4 + Mm04 setup and returned to Seymour duncan pickups.
He know uses a active seymour duncan Blackout AHB1 in the bridge.
This is a pickup similair to a EMG81 but with much better tone and less noise.