Serial numbers — where they actually work

McIntosh Laboratory — A116

· 1 rows · Per-model series: every McIntosh model has its own numbering. Period: January 1953 - July 1954. The letter inside the number is a production-series code, NOT a year.

Marantz — Method 1 — numbering bases (method description)

· 0 rows · Method 1 — purely sequential numbering from a base number. Bases: 0 — models 10, 24; 1000 (1001 in the mainatework guide) — models 1, 2, 3, 4, 5, 8, 8B, 9, 10B, 15, 16, 18, 19, 20, 20B, 22, 25, 26, 27, 28, 29, 32, 105, 110, 115, 115B, 120, 120B, 125, 150, 240, 250, 250M, 500, 510M, 1030, 1040, 1060, 1070, 1200, 2010, 2015, 2200, 2220B, 2230, 2240, 2245, 2270, 2440, 3300, 3600, 3800, 4060, 4100, 4220, 4230, 4240, 4270, 4415, 4430; 10000 (10001) — models 7, 7C, 7T; 100000 (100001) — 2235, 2250B. The suffix “J4” = universal transformer (100/120/200/220/240 V). For models 1030, 1040, 1060, 1070, 2010, 2015, 2220, 2220B, 2230, 2235, 2240, 2245, 2270, 2275, 2440 the numbering depends on the market: USA from 1001, Europe from 50001, Canada from 60001, Asia from 80001.

Quad (Acoustical Manufacturing) — QCII Control Unit

· 13 rows · Official Quad table (PDF, page 2): each model gives the serial-number counter at the end of the year. It is a year, not a month; the table does not separate the mono/stereo runs of the 1959 changeover. Production 1953-1959, 20000 units sold.

Thorens — Thorens TD-124 / TD-124 Mk II

· 13 rows · One continuous numbering from no. 1001 (1957); when the Mk I → Mk II change happened, the numbering was NOT restarted. The number is on the chassis (sometimes a label or an engraving). The RetroTone table is a compilation of live units, dated receipts/invoices and Joachim Bung's research: accuracy ≈ ±half a year to a year, and the numbers cannot be divided evenly between years (the production rate varied). Documented points: no. 1102 — the first 1–2 months of production; no. 14,302 ≈ 1959; no. 29,304 — a dealer invoice of December 1961; no. 40,000 — a receipt of 21.03.1964; no. 59,222 — late Mk I, no. 59,320 — early Mk II (the changeover ≈59,000, spring 1965). The switch to the other bearing type — ≈7,000–8,000; the dark green inner platter — below ≈30,000. Year of sale ≠ year of manufacture: units from stock were still sold in the late 1960s.

Revox (Willi Studer) — Revox A77 — machines assembled in Switzerland (prefix S)

· 4 rows · Prefix S = Made in Switzerland (Regensdorf), G = Löffingen/West Germany; the prefix is the place of assembly, NOT the version. About 72,800 Swiss and 289,730 German machines in total (QRG). The versions ran as parallel S and G streams, which is why one Mk version has two ranges. An exact date comes only from the month/year stamp on the reel-motor rotors (and on the heads of some machines): the part has to be removed. Changes by number: S 15 500 / G 16 150 — new capstan motor (+20 V supply, different mains transformer); S 37 751 / G 43 228 — different pinch-roller solenoid; S 60 483 / G 78 003 — capstan motor on sleeve bearings instead of ball bearings; G 111 813 — different brake drum; G 267 100 — calibration on Revox 621 tape; G 277 664 / G 279 969 — different speakers (case only).

Dynaco — Dynaco serial-number formula (product code + year + week)

· 11 rows · The formula (from Ronaldw441's post in rec.audio.tubes, 14.12.1996, mirrored at geocities.ws/mnowlen/dynaco.htm; it “works” on the author's own units): [1st, sometimes 1st–2nd digit = product code in order of introduction into the range][next digit = year of manufacture][2 digits = week][3 digits = unit number within the week]. Example: 3 809 077 → code 3 = Mark III, 8 = year (1958 OR 1968 — the decade is not distinguishable in the number), 09 = ninth week, 077 = number within the week. The product-code list is incomplete: the source itself marks some entries with a “?”. The ranges below are given as “product code × 10^6” — that is a way to separate one product from another, NOT a factory range: the year is determined by the digits after the code, so a decoder must implement the formula, not just a range lookup.

Fisher Radio (The Fisher) — 100 Amplifier SM

· 1 rows · Brackets = the applicability bounds of the manuals (Vintage Radio Publishing / fisherconsoles.com). There is no dating.

Garrard Engineering — Garrard 301 / 301 transcription turntable

· 5 rows · No Garrard factory registers survived. What works is the combination: Schedule 1 (51400/1, 1953–1957, grease bearing) and Schedule 2 (51400/2, 1957–1965, oil bearing), the cosmetics/faceplates and the rule of thumb “≈7,000 units a year”: year ≈ (serial number / 7000) + 1954. The same rule of thumb is reproduced by the only ready-made 301/401 decoder (serial-number-decoder.com), so all the year assignments below are approximate. The best independent witness of the year is the ink stamp “year + week” on the underside of the deck (the Garrard Matters community).

Sansui Electric — 1000A

· 4 rows · Nine- and eight-digit numbers: the year digit is the third (9 digits) / the second (8 digits); the first 1–2 digits are the line. The ranges are line + year digit, not factory boundaries; observations: 8.