A short and unusual line. The tweed 5F10 Harvard is the only true member: a compact single-channel amp that, unlike its Champ and Princeton stablemates, ran a fixed-bias push-pull pair of 6V6s driven by a cathodyne phase inverter — more power stage than a student amp but with a deliberately spare front end. The later 6G10 shares the Harvard name in cosmetics only; it was a leftover-parts oddity built on single-ended tweed Princeton chassis, not a continuation of the 5F10's push-pull design.
| Designation | Years | Watts | Output stage | Key change | Circuit |
|---|---|---|---|---|---|
| 5F10 | 1955–1961 | 10 W | push-pull 2x6V6GT | The Harvard proper: a two-stage single channel with only a volume and a treble-cut control, feeding a 12AX7 cathodyne phase inverter and a fixed-bias push-pull pair of 6V6GTs (a selenium rectifier supplies the negative bias). Rated at 10 watts, it is the push-pull middle ground between the single-ended Champ/Princeton and the larger Deluxe. The preamp valve is listed as 6AV6 or 6AT6 across the run; the corpus's documented 5F10 carries the 6AT6. | 5F10 circuit ↗ |
| 6G10 | 1962–1963 | 5 W | single-ended 6V6 | Not a push-pull Harvard at all. This rare model reused leftover tweed 5F2-A Princeton chassis and cabinets after the brown Princeton launched, so it is a single-ended 6V6 circuit — essentially a rebadged tweed Princeton wearing the Harvard name (some shipped with 5F2-A tube charts, the Princeton name struck out). It breaks the 5F10's push-pull identity rather than continuing it; no derivation from the 5F10 is claimed here. | 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.
The Harvard is effectively a one-model family: the 5F10 is the only amp built as a Harvard from the ground up. The 6G10 is a name-only continuation on single-ended Princeton chassis and is included for completeness, flagged as such — the two do not share a power-stage topology. 6G10 wattage follows the single-ended 6V6 5F2-A chassis it was assembled from and is approximate. Marketing names are used descriptively.
Every model above carries its own citations in the corpus data file. Browse the full source list for this line: history/families/harvard.yaml.