Building 1x12 Marshall box type 1931B

[guitarman555]

I wanna build my copy of 1x12 Marshall box 1931 B for my greenback (G12H -T 1217 from 1972) i. I have my first greenback (also G12H -T 1217 from 1972) installed into 1x12 1931 A box and sounds great. I wanna have two 1x12 boxes. It is great for versatility (small gigs only one box, bigger gix both boxes). Do you have any typs, about measurment, material, thickness of walls? I have 8 mm plywood (to front I would buy 15 mm plywood)? Do you think it could be enough thick? I measured on my original 1931A box thickness 13 mm everywhere + cca 2 mm tolex. And how about grill? Also, 1931 box has a plank across the speaker in front (it serves for holding Marshall logo - I am thinking if to copy even this or if it will perhaps sound better without this). I am not sure what is the material in front, it is taugher material than on fender amps. Amp that I use is Marshall PA20 from 1972. Thanks for any advices.

 

[fitz]

I wanna build my copy of 1x12 Marshall box 1931 B for my greenback (G12H -T 1217 from 1972) i. I have my first greenback (also G12H -T 1217 from 1972) installed into 1x12 1931 A box and sounds great. I wanna have two 1x12 boxes. It is great for versatility (small gigs only one box, bigger gix both boxes). Do you have any typs, about measurment, material, thickness of walls? I have 8 mm plywood (to front I would buy 15 mm plywood)? Do you think it could be enough thick? I measured on my original 1931A box thickness 13 mm everywhere + cca 2 mm tolex. And how about grill? I am not sure what is the material in front, it is taugher material than on fender amps. Amp that I use is Marshall PA20 from 1972. Thanks for any advices.

1 - Materials / measurements:
Use wood of choice as close to the thickness as original as possible.
Nothing should be as thin as 8mm - 15mm would be better for the sides, 12mm ok for baffle & back panels.
Outside dimensions of the cab build are more important than exact material thickness to match your A Cab
Use the same overall dimensions as your A, except make the top the same depth as the bottom.
There may be a slight angle on the B cab baffle - hard to tell from pics I see online.

2. Grill / tolex.
Matching the existing may be next to impossible.
To get the length of tolex for a one seam wrap, the width would be enough to redo both cabs.
Same goes for the grill cloth, a match may be impossible, but to get enough for one cab, you'll have enough for both.
Lots of different web sites to get tolex, grill cloth, piping, corners, feet, handles, etc...

Logos available at Tubes & More (Antique Electronic Supply), a.k.a. Amplified Parts.