8080 Valvestate V80, 80W 1×12″ combo. This amp was fitted with a 12″ Celestion G12T T4354 8Ω speaker. Schematic of the pre amp. 1991). Schematic of the power amp, Issue 9 (Marshall, 1994). Valvestate owners manual. Photograph of an 8080 combo. 8100 Valvestate, 100W head. The 8412 cabinet was meant to be used with this head. Schematic.. To achieve the full dynamic potential of Valvestate power, we designed pre-amp sections of incredible versatility, with masses of gain and the widest tone control possibilities. Models 8040, 8080, 8100, 8240, 8280 and 8200 feature a Marshall ECC 83/12 AX7 valve in the pre-amp to give even greater dynamics by providing real valve overdrive.