Did Leak publish serial tables?

Never; the model years come from the brand's own timeline.

What dates a Leak Stereo 20?

The dated label inside the chassis (a documented 1961 unit exists) together with the British capacitor codes — labels and capacitors both change in restorations, so the archive pairs them.

What capacitors came in a Leak?

The original coupling capacitors were 0.25 uF Hunts or TCC — which makes a Leak a prime target for the UK date-code layer.

The maker's archive

H.J. Leak & Co. hi-fi.

Leak never published serial-number tables. What works instead is the dated label inside the chassis, the British capacitor date codes on the parts (Hunts, Erie, TCC, Mullard) and the cosmetics — so a Leak is dated to a period, and often to the year, without its serial number being involved at all.

Country: UK
Active since: 1934
Coverage: 1948–2023 · 16 code systems
Dating tier: Codes only
In the archive: 0 series · 16 code systems · 12 models
Years documented: 1948–2023

What dates this maker

Dated label inside the chassis — the maker's own assembly date where it survives.
British capacitor date codes — Hunts three-letter codes and Mullard/TCC equivalents on the parts.
Model cosmetics: the Stereo 20, TL/12 and Varislope lines changed finishes within their runs.

Watch out

A Leak serial number carries no year: do not quote one.
Capacitor codes date the capacitor — a restored unit is full of newer parts than its chassis.

Leak: the label with a date inside the chassis, plus component date codeslate 1940s-1969 · 3 rows · Low confidence

Leak model eras and cosmetic eraslate 1940s-1969 · 9 rows · Medium confidence

Hunts capacitor date code (WHITSUNDAY)1950s-1969 (Hunts taken over by Erie in the late 1960s, probably 1969) · 25 rows · Medium confidence

British year-letter date codes (TCC, Dubilier, Radiospares, Woden, Welwyn)1950s-1960s · 4 rows · Medium confidence

Mullard 'mustard' capacitor date codelate 1963 onwards (used occasionally in late 1963, more frequently from mid 1964) · 3 rows · Medium confidence

Egen potentiometer date code1960-1964 (year letters documented by the source) · 2 rows · Medium confidence

EIA component source/date codeswhole vintage period · 1 rows · High confidence

Safety warnings that apply to any vintage valve hi-fiwhole vintage period · 4 rows · High confidence

Japanese electrolytic capacitor date codes - the shared YYWW mechanicdocumented samples 1993-2023; no maker states when a format started or ended · 0 rows · Medium confidence

Nippon Chemi-Con date code (year digit + bracketed character)2000s production (the repair page was published November 2005) · 2 rows · Low confidence

Nichicon date code (plant letter + YYWW)1990s-2010s (documented 1993 and 2013 samples, same format) · 4 rows · Medium confidence

ELNA date code (four digits, YYWW)1990s-2000s (documented 2000 and 2003 samples) · 2 rows · Medium confidence

Rubycon date code (plant letter + YYWW)1990s-2000s (documented 2002 and 2008 samples) · 3 rows · Medium confidence

Matsushita / Panasonic lot-code date (xYMD), SMD parts2020s SMD parts (documented example decoded as April 2023) · 1 rows · Low confidence

Nichicon month letters J-Z (official notice, power capacitors and reactors)2004 production numbers; the notice itself is dated 2022-04-01 · 4 rows · High confidence

Class A heat, bias and the dating trap - safety notes for this wavewhole Class A vintage period (1967-present) · 3 rows · High confidence

12 H.J. Leak & Co. models are catalogued with their production years, specs and safety notes.