The 'Amp' that John Deacon built was for Brian May and wasn't part of John's own bass gear. Recently Vox made a little white combo that apparently sounds like this famous little radio box that Brian may used on early Queen recordings. I know that among others, John Deacon mainly used Sunn 4x12 cabs. Can't comment on his amps tho. try these resources http://www.deaky.com http://en.wikipedia.org/wiki/John_Deacon