Transformer company EIA codes

There are several ways of identifying a manufacturer, or particular part number of a component in most audio gear that's been manufactured since the mid 1950s.  There's an EIA (Electronic Industries Association) code that identifies the manufacturer, or company, sometimes stamped (either in ink, or metal embossing, or ID tag) on the particular component - in this case the transformer.  Sometimes there is also another series of numbers stamped on the piece, this is the OEM (Original Equipment Manufacturer) part numbers above or below the EIA code, and in some cases parts makers elected not to include the EIA codes, so not all parts have them. These "Code" formats were not completely standardized, but a little deciphering will generally yield the info that's needed to identify the transformer in question. For example if you have 606-432 on a transformer, you can tell that it's a Schumacher transformer from the '606',  the year is either 1974, or a 1964, from the '4', and the '32' is the week of production. The model type, or number, is sometimes stamped on the transformer frame, or bell,  as well; for example 022798, telling us that this is the power transformer from a Fender Super Reverb.

    Below is a list I've compiled with some of the most common transformers used in audio/music today:

Transformers

 EIA code

Stancor  (Chicago - Standard)

138

General Radio

194

Thordarsen - Meissner

238

Altec Lansing-Peerless

391

General Transformer

412

United Transformer Corp (UTC)

418

Standard Winding Co

550

Woodward - Schumacher

606

Ampeg (company?) 616

Electrical Windings (now TMI)

682

Triad

 830

American Transformer

 892

(Pacific?) - TMI

 1052

If you see any irregularities, or know of any other information that might be useful on this page please feel free to contact me: e-mail: Ron@unclespot.com, or call: (209) 606-6467

OTHER interesting/useful transformer pages:
*FENDER TRANSFORMER CHART
*FENDER TRANSFORMER SPECS