John Evans was a pseudonym for Belgian bandleader Francis Bay (1914-2005). You can read more about Bay at Space Age Pop Music.
Bay used the Evans name on several albums in the early 1960s for Directional Records, an imprint of Premier Albums, a company that was notorious for its poor quality budget label pressings. Although the LPs on Directional were a step above the usual quality of Premier product, they still fell far short of those being issued by such labels as London Phase4 and Command Records.
Premier aimed its Directional product at the same market as Phase4 and Command -- stereophiles looking for albums to show off their stereo systems. Premier even copied Command's style of art work and gatefold covers for the Directional albums.
The Directional label had a very short life span, even though Premier ran a full page ad in the Nov. 6, 1961 issue of Billboard espousing the imprint's supposed technical superiority.
Latin Brass was the first release on Directional Records. A sample track can be had below.
April in Portugal
To make matters worse, all of the tracks on Latin Brass had been released on earlier albums under the Francis Bay name on such labels as Omega and Phillips. Some reverb was apparently added for the Latin Brass release in a weak attempt to live up to the "Directional" sound claim.
Here's a further sampling of Bay's Latin sound, this time under his own name on the Phillips label.