Can Sugden date my amplifier?

Yes — the factory answers email queries (model + serial, in the A48 3279 format) with the build year and territory; no public table exists.

How old is the A21 design?

From 1967, and some version of it has been built ever since — the variant, not the name, is what dates a unit.

What is the Richard Allan badge?

The earliest A21s (1967–1968) were badged Richard Allan before becoming SUGDEN — the earliest evidence of the line.

The maker's archive

J.E. Sugden & Sons hi-fi.

J.E. Sugden of Yorkshire built the A21 from 1967 and has made some version of it ever since — the longest continuously produced Class A amplifier there is. The maker publishes an ampography with the production years of each variant.

Country: UK
Active since: 1967
Coverage: 1960–2023 · 19 code systems
Dating tier: Codes only
In the archive: 0 series · 19 code systems · 6 models
Years documented: 1960–2023

What dates this maker

No serial-to-year table; the maker answers factory queries (model + serial by email) with the build year and territory.
The A21 variant chain and factory eras from the official ampography.
Component codes on the boards.

Watch out

The A21 name covers six decades of production: the variant — not the model name — is what dates the unit.

Sugden A21 variants: Richard Allan badge, Series 2/3, A21a, A21SE, Signature1967-2015 · 9 rows · High confidence

Sugden factory eras (research, Cleckheaton, Heckmondwike)1967-2023 · 3 rows · High confidence

Sugden Class A heat (safety, not dating)whole A21 production · 1 rows · Medium confidence

Sugden official reference (history, ampography, how-old-is-it)1967-present · 2 rows · High confidence

Japanese capacitor date codes - pointer to the universal layerwhole vintage period · 0 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

6 J.E. Sugden & Sons models are catalogued with their production years, specs and safety notes.