Note
This is essentially a smaller version of the SB-600. It was advertised for use with the SB-300 and appears to have been sold only in Canada. Some Canadian catalog advertising copy refers to the cabinet as being made by Hammond Manufacturing (located in Ontario). Note that the cabinet is not perforated like that of the SB-600.
Variations of the fiberboard back panel have been noted. Some include the holes and terminal strip, some do not. The red and black Heathkit label is the same one found on the GR-81 receiver, and on a few of Heath’s high fidelity and stereo products of the same vintage.
Uses a 3 x 5 inch 8Ω speaker. Uncommon, but several examples have been found.
Photos, general information and specifications from "Heathkit: A Guide to the Amateur Radio Products," by Chuck Penson, WA7ZZE. Used with permission.