"Early photos of King show him playing a mid-Fifties Gibson gold-top Les Paul with P-90 pickups, which he used along with a Gibson GA-40 amplifier. Shortly thereafter, he switched to his trademark Gibson ES-345 guitars, cranked to massive volume through Fender Quad Reverbs." - excerpt from Guitar World's Freddie King lesson article.more
The quad reverb is essentially a silver face twin with four 12's. It pushes a TON of air which is great for a rhythm player like me. I had mine "blackfaced" to bring it down from 135 watts to 85 or whatever the blackface specs are. This allows you to get more tone before achieving painful volume. It's still plenty loud.
I got my '72 quad reverb with the incorrect assumption that I would gig with it. It's too much of a hassle to move and most clubs that i play are just way to small to warrant an amp this big so it rests in my band's studio getting use on recordings and in my daydreams of when I have roadies.