It was a 300B kit Tim De Paravicini designed for Hi-Fi World of U.K near the end 80's or early 90's, which was later revised by Andy Grove.
Excellent transformers as per Tims usual, but he never was really nuts about the 300B and thus did not pursue using this tube in future designs.
(wonderco_buy79) has one for sale on the bay at the moment which is what I imagine sparked your interest ?
