Marshall became so busy producing their amplifiers that they appointed an outside firm, Rose Morris of London, to handle the sales and distribution of their products.
The relationship between manufacturer and distributor soon became strained. As Marshall's manufacturing capability grew, they pressed Rose Morris for more and more sales. Furthermore, Marshall was displeased with the 55% premium Rose Morris added to the price of the amps when sold internationally.
Rose Morris Purchases Vox
While the popularity of Marshall amps continued to grow, Vox was getting little traction in the marketplace. After five years of middling sales, Dallas Industries decided to put Vox on the market in 1978. Rose Morris was able to purchase Vox from Dallas for a bargain price.
Rose Morris feared that their Marshall distribution was nearing an end. Should they lose Marshall, Rose Morris would shift their efforts towards Vox.
Marshall refused to renew their distribution contract with Rose Morris when it expired in 1980.
The Concert 100
After Rose Morris and Marshall parted ways, Rose Morris was freed from the concern of building Vox amplifiers that too closely resembled a Marshall. Introduced in 1987, the Vox Concert 100 closely followed the design of the Marshall 100 stack.
The preamp section for the single channel Vox Concert 100 head featured three 12AX7 (ECC83) tubes plus Volume, Gain, Bass, Middle, Treble and Presence controls. Like a 100 watt Marshall, the power amplifier stage was powered by four EL-34 tubes.
The 4x12 enclosure was available as a slant baffle (similar to the Marshall 1960A) or as a straight baffle (similar to the Marshall 1960B) enclosure and either featured an oversized Vox logo. The cabinets were rated at 8 ohms and loaded with four Celestion G12T-75 speakers.
My thanks to Kenny Howes for the photographs of his Vox Concert 100 half stack.