Standel beat Fender to market with a solid-state amp by 1964, after Crooks began experimenting with semi-conductors in 1961 and produced a hybrid tube/solid-state design.
Marks that can be entered for this maker: Transformer code.
Nothing predates 1964; components only push the date later.
Sold-price aggregates are not collected yet, so the archive gives no figure — condition, originality of the transformers and a documented recap move this model more than any list price.
Evidence: Vintage Guitar magazine · Standel — maker history