60W 1x15 JBL bass/guitar head with 2 x 6550 — the Tualatin-era foundation of the Sunn line.
Marks that can be entered for this maker: Transformer code.
Nothing predates 1960; 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: Blue Book of Guitar Values — sunn