I'm comparing the 8 ohm and 16 ohm versions of the most classic Blackback, i.e. the G12M25 75Hz that AC/DC, Van Halen and Kiss used. The 16 ohm version was denoted T1221 and the 8 ohm version T1220. I'm comparing a quad of 1977 T1220 8 ohm Blackbacks to two quads of 1975 and 1976 T1221 16 ohm Blackbacks. I'm using a 1973 Marshall JMP 50W Lead model no 1987 and 2008 Gibson Les Paul R9 with a Seymour Duncan Alnico 2 Pro in the bridge. I'm only using close mics here: Sennhesier MD421U5 and a Unidynr IV 548.
