Ampex Grandmaster (c. 1974–1990s)

Little independent documentation exists for the Ampex Grandmaster. Almost everything that survives is Ampex's own advertising. The name belonged to the company's professional mastering tape line, most commonly associated with the 456 formulation. Ampex's ads in DB Magazine (Dec 1974, p.25) and Recording Engineer (Dec 1974, p.4) touted Grand Master as a brand-new, "super-hot" tape that worked with your same bias setup, with a claimed 74 dB S/N ratio and up to 3 dB extra sensitivity. The same advertising said every reel of 2-inch Grand Master was tested end-to-end for session-spoiling dropouts before shipping.

By 1977, Studio Sound (Aug 1977, p.65) was listing Ampex Grandmaster 456 as studio mastering tape alongside Ampex 406. The name still appeared in Audio's open-reel blank tape directory in November 1979 (p.56). The line carried on into the 1990s. Ampex was advertising 499 Grand Master Gold in Recording Engineer (Jan 1992, p.41), describing it as engineered to exceed expectations with low print-through, low noise, low distortion, and high output. Grandmaster is less a single model than a family of professional open-reel formulations that anchored Ampex's studio business for nearly two decades.

Type: professional open-reel mastering tape (formulations include 456, later 499 Grand Master Gold)
Claimed S/N ratio (1974 ad): 74 dB
Claimed sensitivity improvement: up to 3 dB extra
Reel widths mentioned in period sources: 2-inch, 1-inch