How to date a vintage organ.
Three routes, in order of precision. Every claim below cites its source on the brand pages.
1 · Serial number tables (where they exist)
Hammond is the deep end: 160 published production blocks across 42 model series, built from owner registrations in the community Age Determination List. The catch: numbers are per model group, not one global sequence — the model on the plate decides the rows. Leslie sits in between: community tables exist but the list itself warns of ±1–2 years imprecision.
2 · Technology eras (when tables do not exist)
Most church and home brands never published charts. Their organs still betray their decade: tube circuits read 1950s–60s, discrete transistors late 1960s–70s, microchips and digital labelling from 1971 (Allen, the world’s first digital organ) and ~1980 (Yamaha Electone). Anchor events: Gulbransen’s first transistor organ 1957, Rodgers from 1958, Electone debut 1959.
3 · Component date codes (the exact-year route)
Transformers, pots and speakers carry EIA date codes — maker code plus year and week (926 = Todd Electric in many Fishers, 137 = CTS). Leslie motors are stamped week-year (7245 = week 45 of 1972). Hammond’s AO-28 transformer is silver before 1963 and black from 1963, with a 4-digit date on the bell. These codes survive when serial knowledge does not.
Where the plate lives, by maker
| Maker | Serial location |
|---|---|
| Hammond | Under the lower keyboard, left or right side — typical on 1970s models and later. |
| Leslie | Serial number on the amplifier chassis inside the cabinet. |
| Allen | Model/serial plate screwed to the inner side of the top rail that runs across the back of the organ — lift the top (screws underneath, at the sides). |
| Rodgers | Model/serial plate under the keydesk — literally: lie on the floor and look up at the underside of the keyboard assembly. |
| Yamaha Electone | Name plate with model, serial and power data — underside or back of the instrument (see the diagram in your model’s owner’s manual, section "NAME PLATE LOCATION"). |
| Lowrey | Plate right under the keyboard — often on the underside of the manuals, not the back panel. Bring a flashlight. |
| Baldwin | Plate location for Baldwin organs is not documented in public sources we could verify — check the usual spots: underside of the keydesk and the rear rail. |
| Wurlitzer | Plate location is not documented in public sources we could verify — check the keydesk underside and rear rail. |
| Conn Organ | Tag on the underside of the keyshelf, at the treble (right-hand) end. |
| Thomas | Plate location is not documented in public sources we could verify — check the keydesk underside. |
| Gulbransen | Plate location is not documented in public sources we could verify — check the keydesk underside and rear rail. |
| Kimball | Plate location is not documented in public sources we could verify — check the keydesk underside. |
| Estey | Branded label on the top surface of the sound board — remove the rear panel (and possibly a layer of dust). |
| Mason & Hamlin | Same route as other reed organs: maker labels on the sound board or rear frame; numbers stamped or stencilled. |
Frequently asked
Can every organ be dated exactly?
No. Hammond tonewheel organs can be dated to a production block (often to the year), Leslie cabinets to roughly ±1–2 years. For most other makers the honest answer is an era window derived from model, technology and component date codes.
What are component date codes?
Electronic components were date-stamped. Transformers, potentiometers and speakers carry EIA codes (three-digit maker code + year + week), Leslie motors carry week-year stamps (7245 = week 45 of 1972), and Hammond preamp transformers changed colour in 1963. These give exact years even when serial charts do not exist.
Why does a letter appear on 1969–1973 Hammond plates?
During that window Hammond stamped a leading letter that sets the year — A=1969 through E=1973. The prefix was dropped mid-1973, which is why digit-only tables have a gap there.