One of these recently sold on eBay. Two 12AX7s (according to the Schematic, one of which has only one side wired), one 7247, 7591s out, and a solid state rectifier. Vol/bass/treble, bright switch, and master volume controls. 15" speaker. The 7247, a tube that is 1/2 of a 12AX7 and 1/2 of a 12AU7, made its first Guild appearance in the first Thunderbird. The 12AX7 1/2 used as a final gain stage and the 12AU7 1/2, with its higher voltage handling characteristics, as the driver/phase inverter. The 7247, a/k/a 12DW7, was used as the P/I in all Guild heads and combos until the early '70s.