This S.B.S. has some of the niciest guitar tone ever!
its not quite the same, but very close anyway. my favourite sabbath tone is the first album, which of course was P90s into a Rangemaster boosted Laney Supergroup... you can hear the difference with the next album where the Rangemaster was modded. Anyway, I think he kept using the P90s for some time and switched to a John Birch from Technical Ecstacy onwards.. Nevertheless I also understand his earlier Gibsons were heavily modded by John Birch, and theres a pictures of his 'monkey' Gibson SG retrofitted with John Birch pickups. No idea when this would have been done.
Whatever he used in the early period, theres no doubt these Hyperflux pickups get that tone instantly, you can get within spitting distance of anything from Master Of Reality tone onwards with it. I'm not even using a Laney amp, but a Marshall. A treble booster does help get closer, but even plugged straight in its practically there.
On the Never Say Die tour, which you can get many clips of on you tube, you can clearly see his playing a John Birch for the whole gig.
Sabbath had an amazing run of albums - six utter classics in a row!! (even if I don't so much like Volume 4) Few bands, if any, can boast that (maybe Kraftwerk is the only other)! When I started playing I was a massive Iommi fan, and picked up the guitar because of him. In the last couple of years I forgot my Iommi and Black Sabbath love, listening more to Judas Priest and The Scorpions. Let me tell you I'm straight back there now with this axe!!