Why did Pioneer chose Sony to make two premier models with their name on them? Specifically the Sony SL-HF400 is the Pioneer VX-50 and the Sony SL-HF900 is the VX-90. They are identical except for superficial cosmetics, and the addition in the back of two jacks for Pioneers exclusive SR control system. When these two models came out they had a central control system called SR that centralized control of all your Pioneer equipment from to just one source. It was similar to Sony's Control-S system, for which they also have jacks on the back. Pioneer evidently looked at and liked the Beta system enough, and more pointedly, the 400 and 900 enough to choose them as the VCRs they wanted integrated into their SR system.