History · Fender-style

The Champ line

Fender's smallest student amplifier and its longest-lived circuit idea: a single-ended power tube, no phase inverter, no tone stack. The line begins with the late-1940s Champion student amps, passes through the tweed 5-series revisions that swapped an octal pentode preamp for a 12AX7, reaches its most copied form as the 5F1, and continues under blackface (AA764) and silverface cosmetics into the early 1980s. Throughout, the output stage stays a single cathode-biased 6V6 — the defining constant of the family.

1948–1968 7 models 2 documented 5 history-tier

Era timeline — each bar spans a model's production years; the chain from top to bottom is the line's succession.

Documented circuit — links to its page History-tier — placed & sourced, circuit not yet drawn Succession within the line

The models

Designation	Years	Watts	Output stage	Key change	Circuit
800	1948–1949	4 W	single-ended 6V6	The first entry in the line and Fender's earliest student amp: a single octal pentode preamp driving one single-ended 6V6, in a TV-front cabinet with an 8-inch speaker (the "800"). Output rating is approximate — these were never formally catalogued with a wattage figure.	history entry
5B1	1949–1953	4 W	single-ended 6V6	Same single-ended 6V6 recipe stepped down to a 6-inch speaker (hence "600") in a two-tone cabinet, carrying a 6SJ7 pentode preamp, 6V6 output and 5Y3 rectifier. Dating is soft: the Champion 600 name spans roughly 1949 into the mid-1950s and overlaps the wide-panel tweed 5C1 revision.	history entry
5C1	1953–1955	4 W	single-ended 6V6	The Champion 600 circuit carried into a wide-panel tweed cabinet as the model name shifted toward "Champ." Topology is essentially unchanged from the 5B1 — still a 6SJ7 pentode front end into a single-ended 6V6. Tweed-era dates are approximate.	history entry
5D1	1954–1955	4 W	single-ended 6V6	A short-lived component revision within the wide-panel tweed era, still built around the 6SJ7 pentode preamp and single-ended 6V6. It sits between the 5C1 and the 12AX7-based 5E1; exact start/end dates overlap its neighbours and are not firmly documented.	history entry
5E1	1955–1957	5 W	single-ended 6V6	The pivotal revision: the octal 6SJ7 pentode preamp is replaced by a 12AX7 twin triode used as two cascaded gain stages, in a narrow-panel tweed cabinet. This is the two-triode, single-ended 6V6 architecture the rest of the line keeps.	5E1 circuit ↗
5F1	1958–1964	5 W	single-ended 6V6	The definitive tweed Champ and the most reproduced circuit in the line: the 5E1's two-stage 12AX7 into a single-ended 6V6, with an 8-inch speaker and revised power-supply filtering. Topology is a light refinement of the 5E1 rather than a redesign.	5F1 circuit ↗
AA764	1964–1968	5 W	single-ended 6V6	Blackface cosmetics and a new circuit number, but the output stage stays a single-ended 6V6. The AA764 renumbering coincides with the tremolo-equipped Vibro Champ sibling, which adds a tube tremolo oscillator ahead of the same power stage; the plain Champ omits it.	history entry

A circuit ↗ badge links a fully documented circuit — redrawn schematic, verified operating point, parts list. A history entry is placed and sourced here but its circuit isn't drawn yet; contributions are welcome.

Dating & notes

Tweed-era production dates (5B1 through 5D1) are fuzzy and overlap between revisions; the ranges given are the defensible spans, not firm year-by-year boundaries. Wattage figures for the pre-5E1 Champions were never formally catalogued and are approximate. After the AA764, the Champ and Vibro Champ continued under silverface cosmetics from 1968 into the early 1980s (with a brief blackface reissue near the end) — the single-ended 6V6 output stage unchanged throughout. Marketing names are used descriptively.

Sources

Every model above carries its own citations in the corpus data file. Browse the full source list for this line: history/families/champ.yaml.

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