Marshall VBA400 Schematics
The VBA400 is a kick ass all tube 400W bass amp and was probably introduced in 1998. It was fitted with 8 Svetlana/SED 6550C power tubes, three ECC83 tubes and an ECC82 tube. It runs off a B+ of 640V with 320V on the screen grids.
VBA400, 400W head
Schematic of the front PCB, VBA4-60-00 Issue 2, (Marshall, 1998).
Schematic of the PSU, VBA4-61-00 Issue 4, (Marshall, 1999).
Schematic of the back PCB, VBA4-62-00 Issue 2, (Marshall, 1998).
Schematic of the output section, VBA4-63-00 Issue 1, (Marshall, 1998).
Owners manual of the VBA400.
VBC412, 400W 4×12″ 4Ω cabinet
This 4×12″ cabinet is fitted with four 16Ω speakers.
VBC810, 640W 8×10″ 4Ω cabinet
This 8×10″ cabinet is fitted with eight 32Ω speakers.
See the Marshall Amps VBA400 page for more “official” information on these VBA400 amp.