According to Tony's [official site](http://www.iommi.com/equipment/) Tony writes "There were five amp heads stacked up, two [Laney GH 100 TIs](http://equipboard.com/items/laney-ti100-tony-iommi-signature-guitar-amplifier-head), one Laney TT 100, one Paul Reed Smith modified Marshall JCM 800 and one vintage [Vox AC30](http://equipboard.com/items/vox-handwired-ac30-amp-head) head."more
This amp is an amp that is used constantly in my studio. I use this head with a JCM 900 4x12 cabinet, and it gets those classic Marshall tones everyone is talking about. What people do not realize about this amp is that the clean tones are AMAZING. They sparkle, chime, just like any other amp would. But they are original to Marshall. These tones are not meant to emulate a "Fender Clean", or a "Vox Clean". These are Marshall Cleans. I find I have to set this amp a little bit brigher then my normal settings to get the clarity in the overdrive that I am looking for. When you switch to the clean channel, since there is only 1 EQ for 2 channels, the cleans are a bit bright. I woulod recommmend buying an EQ pedal for your clean tone, to bring out the bass frequencies and tone down the highs. I would recommend this amp to anyone who is looking for that classic Marshall look, and is someone who loves that british tone. Great amp overall, and have had no problems.
I have been playing through my dad's old JCM 2000 for a couple of years now, and it has to be one of my favorite sounding amps. I mainly use my PRS Custom 24 through it, and play blues rock stuff on it (a bit of clapton, stones ect.) and it just gets the perfect sound for me.