Vox Transistor Brochures - Thomas Organ (1966) and Jennings (1967)
Below, the Thomas Organ brochure from 1966 setting out the rationale for transistors. This was taken up in 1967 by Jennings and issued with a slightly different cover and other modifications.
The four pictures above, the Thomas Organ brochure
The cover of the Jennings brochure. Notice that the amplifier sections do not have the sloping sides depicted in the Thomas version.
Below, pages from the JMI solid state brochure, printed in black and white in the "Vox Story", ed. Denney and Petersen. The text provided in the American version has been enlarged upon considerably.