An amplifier usually carries more than one date code, and they do not all have the same authority. These ten pages explain what each system is, where it sits, how to read it and what it cannot tell you.
Two letters inside a Fender cabinet: year then month, in a vintage cycle and a reissue cycle that share the same alphabet.
Read the guide ↗Code systemManufacturer, year and week on transformers, speakers, pots and capacitors — the code that dates the part rather than the amp.
Read the guide ↗Code systemFender's dated quality-control sticker on the rear of the chassis, used from 1990 onward.
Read the guide ↗Code systemMarshall barcode labels from October 1992 and date bars from August 1997, read as year, week and sequence.
Read the guide ↗Code systemInk stamps inside Fender chassis, read year-first before 1979 and week-first after it, with M and H assembly stamps.
Read the guide ↗Code systemThe month and year Mesa wrote by hand inside the chassis, and the technician initials and dates added from 2008–09.
Read the guide ↗Code systemFender revision codes such as AA763 and AB763: era markers that are constantly mistaken for build dates.
Read the guide ↗Code systemThe maker codes for Jensen, Oxford, CTS, Utah, Rola, Eminence, JBL and Celestion, and the assembly gap that follows them.
Read the guide ↗Code systemCTS, Stackpole, Clarostat, Mallory and Mel Rain stamps — easy to find, and the weakest evidence in the amplifier.
Read the guide ↗Code systemWhich makers publish serial ranges, which number their amps non-chronologically, and when a serial gives a range instead of a date.
Read the guide ↗| System | Makers |
|---|---|
| Tube Chart | Fender |
| Eia | Fender · Ampeg · Vox · Gibson (amps) · Peavey · Silvertone (Danelectro / Sears) · Mesa/Boogie · Gretsch (amps) · Magnatone (Estey) · Sunn · Standel · Premier (Multivox) · Traynor · Kustom · Hiwatt · Orange |
| Qa Sticker | Fender |
| Barcode | Marshall |
| Chassis Stamp | Fender |
| Born On | Mesa/Boogie · Orange · Vox |
| Circuit Codes | Fender |
| Speaker Codes | Fender · Marshall · Vox · Gibson (amps) |
| Pots | Fender · Gibson (amps) · Peavey |
| Serial Plate | Marshall · Marshall · Ampeg · Fender · Hiwatt · Gretsch (amps) · Supro / Valco |