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Post subject: RCA Matrix Codes  PostPosted: Mar 13, 2009 - 06:12 AM
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Okay, I've been searching around the web for some kind of complete guide to reading RCA Matrix codes. As I couldn't find one source telling me everythng, I cobbled together info from various sources, scanned a few discs and sat down with a beer to write this post. So here goes.

Any disc cut and or/pressed by RCA in the USA was given a unique 8 Digit matrix code. The first four digits can tell you a bit about the disc, especially if you're not sure when it was released, or if it's mono disc or something. As far as I can gather, the system started in 1943 and changed a few times, as detailed below:

1943 - 1954
First and Second Digits: Date of mastering
D3: 1943
D4: 1944
E0: 1950
E1: 1951
E4: 1954

Third Digit: RCA Label the disc was cut for
A: Bluebird (1943-46)
C: Custom Pressing (in-house disc mastering)
E: International (c 1951-53)
F: Ethnic
H: Groove
K: Custom Pressing (in-house disc mastering)
L: Red Seal EP (1952-53)
M: V-Disc (1943)
P: Victor EP (1952-53)
Q: Custom Pressing (outside disc mastering)
R: Red Seal
S: Unknown
T: V-Disc (1943-c 1946) then Children (1954)
V: Victor
X: International (1953-54)

Fourth Digit: Format
B: 10" 78rpm (also 10" 33rpm, 1950-51)
C: 12" 78rpm (also 12" 33rpm 1950-51)
H: 7" 45rpm EP (1953-54)
L: 10" 33rpm (1951-54)
P: 12" 33rpm (1951-54)
S: 7" 78rpm (1951-54) and EP (1952-54)
X: 7" 45rpm (c1950-51)


D6: 1946
V: Victor
B: 10" 78 RPM

(Although this was an Australian pressing on a non-RCA label, they were obviously using metal parts shipped to them from RCA)

1955 - 1962
Changes made to add multiple formats

First Digit: Date of mastering
F: 1955
G: 1956
H: 1957
J: 1958
K: 1959
L: 1960
M: 1961
N: 1962
(I was not used to avoid confusion with 1)

Second Digit: RCA Label the disc was cut for
1: Children
2: Victor, Red Seal and Groove (1961-62)
3: Camden
4: "X" then Vik (until 1958)
5: Groove (1955-57) then Hugo & Luigi (1959-62)
6: Groove (c 1961)
7, 8: Custom Pressing (in-house disc mastering)/Readers’ Digest (c 1960-62)
9: Custom Pressing(outside disc mastering)

Third Digit: Genre/Application
C: Children
J: Jazz
M: Broadcast/Transcription
N: Various Artists/Promotional
O: Custom Pressing
P: Popular
R: Red Seal
S: (unknown)
T: Ethnic
W: Country & Western
Z: International

Fourth Digit: Format
A: Stereo 7" 45rpm
B: Mono 10" 78rpm (1955-58) then master tape (1958-62)
C: Mono 12" 78rpm
E: (unknown) 33rpm (c 1956)
G: Stereo 7" 33rpm EP
H: Mono 45rpm EP
I: Mono 7" 33rpm
L: Mono 10" 33rpm
M: Mono 16" 33rpm
O: Stereo 7" 33rpm
P: Mono 12" 33rpm
Q: Mono 7" 33rpm (multiple selections - "Compact Double 33s")
U: Mono 7" 33rpm EP
V: Mono 7" 78 rpm
W: Mono 7" 45rpm
Y: Stereo 12" 33rpm
Z: Stereo 45rpm EP


J: 1958
2: Victor
P: Popular
W: Mono 7" 45rpm

1963 onwards
Changes made to add labels and discontinue many formats

First Digit: Date of mastering
P: 1963
R: 1964
S: 1965
T: 1966
U: 1967
W: 1968
X: 1969
Z: 1970
A: 1971
B: 1972
C: 1973
D: 1974
E: 1975
F: 1976
G: 1977
H: 1978
J: 1979
K: 1980
L: 1981
M: 1982
N: 1983
O: 1984
P: 1985
R: 1986
S: 1987
T: 1988
U: 1989
V: 1990
W: 1991
Z: 1992
Then start again from A, skipping the same letters that were skipped in that series to avoid confusion.

Second Digit: RCA Label the disc was cut for/Genre
A: Grunt
C: Camden
D: Neon
E: Educational
F: Wooden Nickel
G: Groove
H:Hugo & Luigi (1963-64), Chelsea (1972-73)
J: Children
K: Daybreak
L: Wheel
M:George Jones Musicor masters (1972-73)
N: Various Artists/Promotional
P: Popular (Victor)
R: Red Seal
S: International
T: Gregar (1970-71) then Metromedia (1972-73)
V: Victrola
W: Country & Western
X: Chart
Y: Calendar (later renamed Kirshner)
Z: Colgems
1, 2: Readers' Digest
3, 4: Custom Pressing (in-house disc mastering)
5: Custom Pressing (outside disc mastering)

Third Digit: Format (1)
A: master tape (also B, C)
K: 7" 45rpm
L: 7" 33rpm
P: 10" 33rpm
R: 12" 33prm

Fourth Digit: Format (2)
A: Stereo EP
B: Mono EP
M: Mono
S: Stereo
T: Quadrophonic
1: New York City recording
2: Chicago recording (discontinued in 1973)
3: Hollywood recording
4: Nashville recording
5: Outside recording
6: Foreign recording (?)


P: 1963
3: Custom Pressing (mastered by RCA)
K: 7" 45 RPM
M: Mono

Another thing: Somewhere in the dead wax you might find either an H, I or R. These tell you which RCA plant pressed the disc.

H: Hollywood, California
I: Indianapolis, Indiana
R: Rockaway, New Jersey

Information taken from and

Did I forget anything?
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Post subject: RE: RCA Matrix Codes  PostPosted: Mar 13, 2009 - 12:59 PM

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This is some great information! Thanks for researching and posting it here.

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Post subject:   PostPosted: Sep 24, 2009 - 02:55 PM
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A belated thanks from me as I just joined the forum this month. Yes, very good information and we didn't even have to pay any $$ for it. The RCA info is something I have been seeking for a long time-- I have many Red Seal "box sets" from what I'm assuming to be the 30s and 40's-- and nowhere are there any dates to be found on the packaging or on the discs themselves. I look forward to possibly dating some of my discs now Razz
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Post subject:   PostPosted: Sep 24, 2009 - 03:11 PM

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Excellent work!!!

Do what you dig---dig what you do!!!
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Post subject:   PostPosted: Oct 16, 2009 - 08:20 PM
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Here is some addition RCA info

RCA-Victor Records

Every disc on the RCA label, it's subsidiaries, and indeed the myriad of independent labels which utilised it's mighty mastering and pressing facilities, feature a letters and numbers. During the mid-60's they had four recording hubs of New York, Chicago, Hollywood or Nashville. Their codes can be broken down thus:

As an example I'll use the code "634P-0987". The '634P' is the account number of the client, or the info for the company / person who initialised the account. It has nothing to do with arriving at a release date. The second number '0987' is simply the master number referencing the tape used to make the master.

The other part of the code that is included on independent labels pressed by RCA, as well as the major label itself, is the code which reads as, -e.g. "TK4M-0987". Once again, the second set of numbers refer to the master tape reference number, but the first part of the FOUR DIGIT CODE tells us the following -

Noted by the first letter - see below.

K = 45rpm if there was an L = 7" 33 1/3 rpm; R = 12" 33 1/3 rpm; P = 10" 33 1/3 rpm
(An EP actually retained the 'K' in the third position, while 'B' in the fourth position was mono and 'A' was stereo.)

A '4' = Custom - re-recorded from client's furnished tapes -i.e. the client recorded at their own venues, then took the tapes to any of the RCA studios which then cut the lacquers.
A '5' = Custom job whereby the lacquer was furnished to RCA -i.e. cut at a non-RCA studio.

"M" denotes mono, "S" would denote stereo.

In the example TK4M-0987, the "T" denotes a 1966 year of mastering and not always the actual year of release, but it usually is accurate 95% of the time and is a useful rule of thumb. The RCA year codes are thus -
L - 1960 / M - 1961 / N - 1962 / P - 1963 / R - 1964 / S - 1965 / T - 1966 / U - 1967 / W - 1968 / X - 1969
Z - 1970 / A - 1971 / B - 1972 / C - 1973 / D - 1974

One can then pin-point the disc further, as if the account number, in this case "4", falls BEFORE the "K", then the disc was mastered between January and June of 1966. If the number is after the "K", as in our example TK4M, then it was mastered between July and December, 1966.

In addition to the above, most independent label releases also have a letter stamped into the dead wax which indicates which plant was used -
R - Rockaway, New Jersey,
I - Indianapolis, Indiana, (50 miles Northeast of Bloomington at 7900 Rockville Road)
H - Hollywood, California.

Finally, during 1966, their Chicago studios were apparently so busy that their last set of numbers put the number (3/4/5) in the first position and the year in the second (4TKM!). And as to the period up to 1962, the second position was 7, 8 or 9 (indications same as 3, 4 or 5, respectively, post-1963), 'O' was their code for "Phonograph," and 'W' denoted a 7", 45 RPM release. (i.e. L7OW, M9OW or NO8W).
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Post subject:   PostPosted: Jan 04, 2011 - 10:32 AM

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Another note of interest. That Australian issue Don Gibson single was actually pressed from USA metalwork. Same as a USA original. Apparently RCA shipped metalwork to Australia for pressing there.
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Post subject:   PostPosted: Sep 25, 2013 - 03:50 AM
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I'm fairly new here & I have wondered what those codes were for. Than you for the great info.

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