Can a Sunn be dated by serial number?

No. Sunn numbered non-chronologically, published no ranges and took its own documentation offline when the brand was retired in 2002.

How do I date a Sunn Model T?

By the model era and the build details: the original ran from 1968 to 1975 and a numerically unrelated reissue followed in 1998–2001 with almost no technical similarity.

It began as a family business in Oregon, passed to Hartzell and a Kentucky factory, returned to Oregon, and was bought by Fender; the sources give 1985 and 1987 for that sale and the conflict is left open.

What should I look at first?

The model and its power rating, then the component codes on the transformer and the pots.

The maker's archive

Sunn amps.

Sunn applied serial numbers non-chronologically and never published a range table, and the site that documented the amps went offline when the brand was retired. Dating runs on the model and its era, on the build history of a company that moved between owners, and on EIA component codes.

Country: USA
Active since: 1965
Coverage: 1963–2002 · 3 code systems
Dating tier: Codes only
In the archive: 0 series · 3 code systems · 14 models
Years documented: 1963–2002

Eras

1963–1965

Garage builds

The Sundholm brothers built amplifiers before the company was officially formed, working from David Hafler designs and Dynaco preamps, with some units using modified Dynaco parts.

1965–1972

Tualatin years

Sunn Musical Equipment Company opened its Tualatin, Oregon factory when garage capacity ran out. The tube catalogue of this era includes the 100S, 200S, 1000S, 1200S and 2000S, the Model T, and the Sonic, Spectrum, Solaris and Sonaro combos.

1969–1980s

Ownership changes

In 1969 the brothers disagreed and Con bought Norm's share; three years later Con sold Sunn to Hartzell, which moved the factory to Williamstown, Kentucky before a return to Oregon in the late 1970s. The 1980s solid-state models come from the later years.

1985–2002

Fender and retirement

Fender bought Sunn — the sources give 1985 and 1987 and the conflict is left open — and a short revival produced reissues in 1998–2001 before the brand was retired in 2002.

What dates this maker

The model era table: the tube lines of the late 1960s to mid-1970s, the solid-state family of the 1980s and the 1998–2001 revival each carry production windows.
Build history milestones, which are needed to interpret reused model names such as the Model T.
EIA component codes on transformers and pots — the community's recommended substitute for the useless serial numbers.
Ownership and factory location as a bracket: Oregon, Kentucky, back to Oregon, then Fender.

Watch out

Sunn serial numbers do not date an amp, and no range table was ever published.
The Model T name was reused for a reissue that shares almost no technical similarity with the original.
The year Fender bought Sunn is disputed between two secondary sources and is left unresolved here.

Honest no_data: Sunn serial numbers are not a usable date series. Sunn applied its numbers non-chronologically, no range table was ever published, and the official site that documented the amps was removed when Fender retired the brand in 2002 (sunnamps.com today is an unrelated revival company). Dating a vintage Sunn means: (1) the model and its era — 100S/200S/1000S/2000S, Solaris, Sonaro, Sonic I/II, Spectrum I/II, Model T, and the solid-state Beta Lead family are all catalogued with production windows in the Blue Book listing (see code-tables.json 'model-era'); (2) EIA component codes on transformers (Sunn's founders built from Dynaco-derived parts) and pots; (3) build history — garage-built from 1963-64, Tualatin, Oregon factory from 1965, sold to Hartzell and moved to Williamstown, Kentucky, back to Oregon in the late 1970s, sold to Fender in the mid-1980s, brand revived 1998-2001 and retired in 2002.See the component codes →

14 Sunn models are catalogued with their production years, specs and safety notes.