Year of Manufacture

Estimated Year: 1973 – 1974

How to verify: Sunn serial numbers from this era (yours is clearly stamped A 02028 these are notoriously difficult to link to an exact day because factory logs were lost or inconsistent. However, the 1st Generation "Red Knob" Model T was only produced between late 1973 and 1975. Given the early four-digit sequence following the "A" prefix, yours is firmly an early-production unit from the first year or two of the model's run. 

3. Country and City of Manufacture

Country: United States (Stamped "made in u.s.a. by sunn musical equipment company" on the chassis backplate.

City: Tualatin, Oregon 

The History: While the Sundholm brothers originally started building early Sunn amps out of a garage in nearby Portland, by the time the Model T was engineered and produced in the 1970s, operations had fully moved to their famous factory setup (a converted defunct public swimming pool) in Tualatin, just outside Portland.

4. Production Numbers (How many were made?)

There is no surviving official factory documentation stating the exact production numbers for the 1st Generation Model T.

However, historical consensus among vintage gear archivists estimates that fewer than 1,000 to 1,500 total units of the original 1st Gen style were ever manufactured before Sunn updated the design to the 2nd Generation (which introduced a generalized mid-range shift switch and altered the front graphic layout) in 1976. They are remarkably rare pieces of music history.