1) Old European Characteristic: "250"

HMV N78 (His Masters Voice) and Columbia N78 produced by E.M.I. England. CETRA N78, Italy.

This standard may be also applied to records by Parlophone, Brunswick

Time Constant: 636 µs (250 Hz).

2) Old European Characteristic: "500"

Applicable to many European records produced before 1950, and also to many U.S. companies except RCA Victor, Columbia.

Time Constant: 318 µs (500 Hz).

3) Columbia N78

Time Constants: 530 µs (300 Hz) and 100 µs (1,590 Hz).

4) Columbia LP M33

HMV M33, produced in England.

Vanguard, Bach Guild, Cetra M33, Vox.

Time Constants: 1,590 µs (100 Hz), 318 µs (500 Hz), and 100 µs (1,590 Hz).

5) NAB National Association of Broadcasters

Time Constants: 530 µs (300 Hz) and 100 µs (1,590 Hz).

6) NARTB National Association of Radio and TV Broadcasters

has replaced NAB standard. Applicable to Artist, Capitol, MGM, Westminster (see disk cover), Tempo M33 (approximate char.)

Time Constants: 2,720 µs (60 Hz), 318 µs (500 Hz), and 100 µs (1,590 Hz).

7) AES Audio Engineering Society, made in 1951 this reproduction definition for compatibility to standards mostly used in the USA.

Time Constants: 398 µs (400 Hz) and 64 µs (2,500 Hz).

8) London London Gramophone Corporation

London M33 & M45,Decca (possibly).

Time Constants: 1,590 µs (100 Hz), 318 µs (500 Hz), and 57 µs (2,800 Hz).

9) CCIR Recommendation No. 134

by VIIth Plenary Assembly, 1953: Germany 1952-1955: DGG 33 1/3 LP.

Time Constants: 450 µs (350 Hz), and 50 µs (3,180 Hz).

10) IEC

A recommendation of 1955 for playing N78 disks, according to B.S. No. 128 (British Standard).

Time Constants: 3180 µs (50 Hz), 450 µs (350 Hz), and 50 µs (3,180 Hz).

11) RCA Victor & IEC No.98

refers to this "New Orthophonic" standard since 1952.

Recommendation of 1953 by NARTB, of 1955 by IEC No.98, and B.S. No. 128. World standard since 1967.

Time Constants: 3180 µs (50 Hz), 318 µs (500 Hz), and 75 µs (2,120 Hz).

12) TELDEC

Telefunken and Decca founded a record company that used a characteristic proposed for German DIN-Standard on July 1957:

DIN45533, DIN45536, DIN45537.

Time Constants: 3180 µs (50 Hz), 318 µs (500 Hz), and 50 µs (3,180 Hz).