‘Park’ was a brand that was launched by Marshall during the mid-1960s, and along with a range of amplifiers, Park also sold its own fuzz box. In the same way that Marshall was initially supplied with fuzz boxes by Sola Sound, the Park Fuzz Sound was also a rebranded Sola Sound product.
Production of the Fuzz Sound was ramped up approximately in 1969, when the Fuzz Sound was developed in the same type of enclosure as Sola Sound were already using for the Vox Tone Bender MKIII. This version of the Park Fuzz Sound also featured identical electronics to the MKIII, with a circuit topology that was originally used in the Baldwin-Burns Buzzaround.
The period in which the known surviving Park Fuzz Sounds were built spans from approximately 1969 to the mid-1970s, but the exact year that the Park Fuzz Sound was first released is currently unknown, as there may still be earlier versions that have yet to resurface.
I saw a photo of the two-knob Park on Effects Database and wondered what circuit was inside. It bothered me for a few days then I remembered this site! Thanks for sharing all your fuzz knowledge.