Yeah, that title is clickbait, but hear me out. There is a seller called terrysvintage who has tons of pro audio brochures from the '50s through the '70s. Some amazing stuff - Pultec, Fairchild, Langevin, EMT, Telefunken, and on and on. The "free" part is that they post photos of the docs that are good enough to download and enjoy if you don't want to pay $9.99+ for the paper version. Sample attached.
Standard disclaimers apply: Not my auctions, don't know the seller, no such thing as a free lunch.
Standard disclaimers apply: Not my auctions, don't know the seller, no such thing as a free lunch.