LP Pressing Rings And The Mystery Of The Deep Groove (11/2023 Update)

NB: November 12, 2023 Update.  A big refresh with lots of new plants, updates, and corrections.  As always, this is a work in progress.  Corrections or additions are gratefully accepted.

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In my December, 2016 post, I wrote about how to decipher some of the information in the dead wax in order to figure out such things as which version of an album you have, who cut the lacquer, where it was mastered, and which company pressed the LP. I mentioned that the size of the pressing ring can also be a good way to help determine which company pressed an album. With a number of new pressing plants coming online and a big increase in the number of albums being pressed in Europe, I thought it might be useful to look a little deeper at what the pressing rings can tell us.

Click on the photo to see it larger.

Above are three different pressings of Crosby, Stills, Nash & Young's 1970 hit record Deja Vu. Atlantic Records is a great place to start because they always list the pressing plant on the label. As opposed to many of the other big labels, Atlantic didn't own their own pressing plants. So, they had to contract out for all their releases. At the bottom of every Atlantic label is a number, in the case above, ST-A-701829 [not to be confused with the LP's catalog number, at the top of the label, which is SD 7200.] Atlantic's numbering system is pretty straightforward. In the example above, ST = stereo, A = Atlantic, 70 = the year, and 1829 is the tape master number used to cut the lacquer. After the tape master number is a (mostly) two-letter code that indicates the pressing plant for that particular copy. Here is Atlantic's list of pressing plants:

AM = American Record Pressing Co., Owasso, MI
AR = Allied Record Company, Los Angeles, CA
BW = Bestway Products Inc., Mountainside, NJ
CT/CTH = Columbia Records Pressing Plant, Terre Haute
CP = Columbia Records Pressing Plant, Pitman, NJ
CS/CSM = Columbia Records Pressing Plant, Santa Maria
DCE =  MCA Pressing Plant, Gloversville, NY
DCW = MCA Pressing Plant, Pinckneyville, IL
FT = Fidelatone Mfg., Hawthorne, CA
LY = Shelley Products, Huntington Station, NY
MG = MGM Records Division, Bloomfield, NJ
MO = Monarch Record Mfg. Co., Los Angeles, CA
MS = Midsouth Records, Nashville, TN (rare)
PL = Plastic Products Company, Memphis, TN
PR = Presswell Records, Ancora, NJ
RI = PRC Recording Company, Richmond, IN
SO = Sonic Recording Products, Inc., Holbrook, NY
SP = Specialty Records Corporation, Olyphant, PA
W = Columbia Records Pressing Plant, Carrollton, GA (rare)
WM = Midwest Record Pressing, Inc., Chicago, IL

Pressed by Philips Record Corp., Richmond, IN

If you click on the photo above to enlarge it, you can clearly see that the codes on the three copies of Deja Vu from left to right are MO, PR, and RI. That indicates that the three albums were pressed by: Monarch Records, Los Angeles; Presswell Records, Ancora, NJ; and Philips Recording Corp., Richmond, IN. However, even if they didn't put the code on the label, we could probably figure out the pressing plant anyway, either by looking for MR, PR, or PRC in the dead wax, or by checking the size of the pressing ring -- as long as you know that the pressing rings for Monarch, Presswell, and Philips are 73mm, 32/70mm, and 70mm, respectively. 

When record presses squeeze a biscuit of vinyl, they create a pressing ring (or rings) on each side of the label. The size of the rings depends on the size of the die that the pressing plant used to hold its stampers in place.  Luckily for us, many of the major record manufacturers have different sized rings, which often allows us to figure out where a record was manufactured even if there is no indication in the dead wax.  

In the heyday of LPs - the 1960s, 70s, and 80s, the vast majority of US releases were pressed by plants owned by the major labels such as Columbia, Capitol, and RCA, or by the major independent manufacturers such as Specialty, Rainbo, Monarch, and Presswell. In order to cut down on shipping costs, most major labels had pressing plants in different parts of the country -- typically on the East Coast, in the Midwest, and on the West Coast. Columbia Records, for example, had pressing plants in Pitman, NJ, Terre Haute, IN, and Santa Maria, CA. I live on the east coast, so most of my Columbia albums are from Pitman. [Columbia also had earlier plants that closed in the 60s in Bridgeport, CT and Hollywood, CA, as well as a plant that opened in 1981 in Carrollton, GA.] And just by the way, LondonJazzCollector has a terrific post about the history of the Columbia label.

RCA had three plants in Rockaway, NJ, Indianapolis, and Hollywood, CA, (although Rockaway and Hollywood both closed in the 70s). Other labels had more or fewer plants. Capitol had four plants, in Scranton, PA, Winchester, VA, Jacksonville, IL, and Hollywood, CA. MCA and United Artists had two plants each.

Like Atlantic, Warner Brothers did not press their own records. From 1958-1963, most Warner albums were pressed by RCA at their Rockaway and Indianapolis plants. From 1963-1975, Columbia pressed all Warner albums. Then, beginning in late 1975 - early 1976, Warner moved their pressing to Capitol. Little Feat's The Last Record Album came out in November, 1975, and was released with a Columbia pressing (top) and a Capitol pressing (below). Even if you didn't know that, you could tell by looking at the pressing rings. Columbia's ring is 69mm, while Capitol's is 39mm. 

Columbia's 69mm pressing ring runs through the bottom of the WB logo at the top of the label. 

Capitol's 39mm pressing ring is easy to see.

Over the years I have made a list of record manufacturers and the diameter of their pressing rings. The list is nowhere near exhaustive. Many of the manufacturers on the list are no longer in business.  However, there are also a number of new pressing plants that have opened in the U.S. and abroad, responding to the growing demand for LPs worldwide.  

I use a digital caliper and a ruler (with millimeter markings) to check the ring diameters. And while I try to be precise, I am certain there are errors in my notes.  Likewise, some of my deadwax markings may be wrong.  If you spot any errors or have any additions, I would be happy to add them.  Even though the pressing rings for many U.S. manufacturers are commonly listed in inches, I use millimeters because it's much more precise. Even with a ruler I find it hard to be sure that the ring on a modern Columbia release is exactly 2.71654 inches,

whereas I can easily tell if it's 69mm. (NB: As W.B. mentions in his comment below, a Columbia pressing ring is actually closer to 68.5mm, or 2.69685 inches.  However, for purposes of identification, 69mm is close enough.)

Note that the letters, numbers, words, or symbols in parentheses after the pressing plant name in the left column are plant markings that are commonly found in the dead wax which can help positively identify a plant.  This is particularly important because Columbia's pressing plants in Pitman, Terre Haute, and Santa Maria all had a 69mm pressing ring.  But you can often tell which is which by looking for the letter P, T, or a backwards S in the dead wax. After the diameter size on the right I have included dates that the plant operated (if they only ever had one pressing ring diameter), or dates for a particular pressing ring (if the plant had more than one), letters and/or numbers that indicate the pattern of the catalog number used by a particular pressing plant, and a list of labels the plant regularly pressed for. 

 

REV: November 12, 2023

Pressing Ring Diameters By Size -- Small to Large

Pressing Plant (identifying marks in runout)            Pressing Ring Size (x-x = deep groove, x/x = two rings)

Sun Plastics, East Newark, NJ                                                                                                        11/70mm (outer very faint) 1946-2009 (presses sold to Gotta Groove) 

MPO Moulages et Plastiques de l’Ouest, Averton, France [MPO, MP]                                15/24/32mm (1983-present); 32mm (1965-present); [68-70mm, 66-70mm rare in 1960s]
[Early Keel?] Hauppauge, LI, NY                                                                                                    19/72mm [1959 Bravo, Pickwick]
Polydor France, Paris (label, not sure of pressing plant)                                                        19mm (bare vinyl center)
Shelley Products, Huntington Station, LI, NY [X, LY, 54, SH, S, Ƨ]                                         19mm (1947-1985) styrene; 70mm (1969-85) vinyl; label diameter: 98mm
Shelley Products, Huntington Station, LI, NY [X, LY, 54, SH, S, Ƨ]                                          19/69-72/88mm (1959); 19mm (1947-1985) styrene; 70mm (1969-85) vinyl

Decca Records, New Maiden, UK [ZAL, EAL, ARL)                                                                      19/69-72mm (1958-68); 33mm (1959-80); 69-72mm (1959-68); 25mm (1952-58); 19/95-97mm (1957-59)
Deutsche Grammophon, Phonodisc GmbH, Hannover, Germany [320]                                19/70mm (1971-72); 30mm, (1951-66); 28-30mm (1961-72) [DG, Philips, Polydor]
Phonodisc GmbH (Philips/DG merger), Hannover, Germany [320]                                        19/70mm (1973-78) [Philips, DG, Polydor, Verve, Atlantic]
Polygram Record Service GMBH, Hannover, Germany                                                              19/70mm [1978-85; 1991-92] [Philips, DG, Polydor, Verve, Atlantic]

Decca Records, New Maiden, UK [ZAL, EAL, ARL)                                                                       19/95-97mm (1957-59); 19/69-72mm (1958-68); 33mm (1959-80); 69-72mm (1959-68); 25mm (1952-58)

Hannover, Germany Plant [320]
Deutsche Grammophon, Phonodisc GmbH, Hannover, Germany [320]                                20mm or 19/70mm (1971-72) 30mm, (1951-66); 28-30mm (1961-72)
Phonodisc GmbH (Philips/DG merger), Hannover, Germany [320]                                        20mm or 19/70mm (1973-78) [Philips, DG, Polydor, Verve, Atlantic]
PRS (Polygram Record Service) GMBH, Hannover, Germany [320]                                        20mm (1978-82); 19/70mm (1980-85; 19/70mm (1991-92) [Philips, DG, Polydor]
PDO (Philips/Dupont Optical), GmbH, Hannover, Germany [320]                                         20mm (1986-91); 19/70mm 86-89); 19/70mm 1986-87) [DG, Philips, Polydor]

Abbey Record Manufacturing Comp. East Newark, NJ [AB MO-YR, (A)]                               21mm (side b) /68-72mm (1955-63) 70mm [1962-70] [Prestige, Roulette, Impulse]
P.R. Records Ltd., Harrogate (CD, CED, P, CT, D, E, G, M, P, R, T, PAG)                                   22/33mm (1979-96); 32mm (1980-2001); 35/65mm (1990-92) (Jasmine, Rhapsody)
Synthetic Plastics Company, Newark, NJ [S.P.C.]                                                                         22-26/70mm or 24/70mm (outer faint) [NB: 3 5/8" label] (1949-77)
KM Records, Burbank, CA (KM-#####) (KM+, + +)                                                                    23/70mm (1977-1992) [Impulse, Nautilus]
Philips Records, LTD, London, UK [▽420]                                                                                     21-23/93mm (1959-71) [Prestige, Philips, RCA, Fontana, Mercury]

Philips Holland
Philips Phonografische Industrie (PPI), Baarn, Holland [670]                                                  22-24mm (1954-1962), also 22-24/99mm, 24mm, 24/99mm
Philips Phonografische Industrie (PPI), Baarn, Holland [670]                                                  22-24/99mm (1954-1962), also 22-24mm, 24mm, 24/99mm
Philips Phonografische Industrie (PPI), Baarn, Holland [670]                                                  24mm, 24/99mm (1954-62) also 22-24mm, 22-24mm, 22-24/99mm,
Phonodisc B.V., Baarn, The Netherlands [670]                                                                              22-24mm (1962-66), 30/88mm (1966-1980)
Phonodisc B.V., Baarn, The Netherlands [670]                                                                              30/88mm (1966-1980), 22-24mm (1962-66)
PRS Baarn, The Netherlands [670]                                                                                                    30/88mm, 29/86mm (1980-1993) [SteepleChase]

CBS/Sony Inc. Tokyo, Japan                                                                                                                25mm [1968-89] [Including Epic/Sony 1978-88]

Decca Records, New Maiden, UK [ZAL, EAL, ARL)                                                                         25mm (1952-58); 19/69-72mm (1958-68); 33mm (1959-80); 69-72mm (1959-68); 19/95-97mm (1957-59)

 

Decca Records
Decca Records Pressing Plant, Gloversville, NY [◉, 1]                                                                 25mm [1953-66] 1 in runout, ◉ on side 2 label matrix [Decca East]
Decca Records Pressing Plant, Pinckneyville, Ill [◆, 2]                                                               25mm [1956-66] 2 in runout, ◆ on side 2 of label [Decca West]
Decca Records Pressing Plant, Richmond, IN [◈ 3]                                                                      25mm [1939-56] 3 in runout 1939-52, ◈ side 2 of label (1952-56)
Decca Records Pressing Plant, Bridgeport, CT [4]                                                                         25mm [1938-53] 4 in runout
Decca Records Pressing Plant, Los Angeles, CA [★ 5]                                                                  25mm [1946-54] 5 in runout 1946-49, ★ side 2 of label 1949-54

MCA Records
MCA Records, Gloversville, NY (I, 1, 回-G-回)                                                                                 25mm [1966-2005] (Decca East until 1966) (1966-73, I or 1 in runouts)
MCA Records, Pinckneyville, IL (2, ◈-P-◈)                                                                                     25mm [1966-2007] (Decca West until 1966) (1966-73, ② or 2 in runouts)
MCA Records Canada, Cornwall, ONT ◎-C-◎                                                                                 25mm [1964-1976] (prior to 1970 The Compo Company Ltd.)

MCA Records: some 25/70mm rings seen.

RCA Records
RCA Records, Hollywood, CA (H)                                                                                                        25.5mm 1968/70-1976, 69-70.5mm DG 1941-1970
RCA Records, Indianapolis, IN (I)                                                                                                        25.5mm 1968/70-1987, 69-70.5mm DG 1939-1969/70
RCA Records, Rockaway, NJ (R)                                                                                                           25.5mm 1968/70-1973, 69-70.5mm DG 1954-1969/70
RCA Records, Smiths Falls, Ontario, CA [ACR, AcR, GT]                                                                 25.5mm (1971-81); 69-70.5mm (1954-71); 69-73mm [varies from 71 to 73] (1952-70)

 
Allied Record Company, Los Angeles, CA (AR, EAST, B-#####, 22)                                       26mm (1975-81); 35/70mm (1982-89). Rare: 35mm (1976-83); 73mm (1971-75)
NB: Check carefully for "E A S T" around the center hole (after 1979) = Pressed by Specialty Record Comp. from plates originally made for Allied. Specialty’s 35/70mm outer is more pronounced. A lone "A" embossed in the label area indicates it was pressed at Allied.

1971-75        73mm (only a handful)
1975-81        26mm (after 1981, only test pressings)
1976-83        35mm
1982-89        35/70mm

Cinram, Scarborough, ON, Canada [(CR), CR, CI, 230]                                                                    26/77mm or 29-69mm muffin. 1969-1981
Europadisk, NYC [(EDP), Europadisk DMM]                                                                                      28mm (1985-2004); 35/52mm (1981-83); 35mm (1981-2004)
KM Records, Burbank, CA (KM-#####) (KM+)                                                                                28mm or 28/70mm (1977-90) Teldec vinyl [MHS, Nautilus, Impulse/MCA]
Allied Records, Ltd., London [(ALI)]                                                                                                     28-30mm or 29-32mm (1961-77); 32mm (1959-72; 32/70mm (1962-82)
Deutsche Grammophon, Phonodisc GmbH, Hannover, Germany [320]                                      28-30mm (1961-72); 30mm, (1951-66); 19/80mm (1971-72) [DG, Philips, Polydor]
Unknown German pressing plant (1968)                                                                                            28-31mm deep groove (Reprise, Warner Bros)
Precision Records, Ontario, Canada                                                                                                    28/38/70mm [1961-?] pressed for ARC, ARC Sound
KM Records, Burbank, CA (KM-#####) (KM+)                                                                                28/70mm or 28mm (1977-90) Teldec vinyl [Nautilus, Impulse/MCA, PAJ]

Dixie Record Pressing, Nashville, TN [DRP-XXXX]                                                                            28.5mm (1981-86, rare); 28.5/70mm (1972-99) [Sold presses to United, 2000]

Mid-South Record Pressing, Nashville, TN [MS]                                                                                28.5mm (1965-68); (sold to GRT in 1969)   
GRT Corporation, Nashville, TN (GRT)                                                                                                 28.5mm (1969-77); 28.5/70mm (1974-79); [formerly Mid-South]

Dixie Record Pressing, Nashville, TN [DRP-XXXX]                                                                            28.5/70mm (1972-99); 28.5mm (1981-86, rare) [Sold presses to United, 2000]

GRT Corporation, Nashville, TN (GRT)                                                                                                 28.5/70mm (1974-79); 28.5mm (1969-77); [formerly Mid-South]

QCA Custom Pressing, Cincinatti, OH (QCA) (1966-92)                                                                   29mm (1969-87); 73mm (1966-72); 29/70mm (1977-90); 29/88mm (1984-92)
Record Industry, Haarlem, The Netherlands (XXXXX 1A)                                                               29mm, also 29/70mm, 29/83mm (1998-present) [Sony, EMI, Music on Vinyl]
Vinyl Record Pressing LLC, Jacksonville, FL [VRP]                                                                           29mm [2016-present]
Electrecord, Bucharest, Romania                                                                                                         29-31mm deep groove; 30mm [1932-present]
Allied Records, Ltd., London [(ALI)]                                                                                                     29-32mm or 28-30mm (1961-77); 32mm (1959-72; 32/70mm (1962-82)
His Master's Voice Limited, Wellington, NZ                                                                                      29-32mm (1954-1972); 32mm (1962-73)
Teldec-Press GmbH, Nortorf, Germany [Manufactured in Germany]                                           29-32mm (1951-65); 29-32/70mm (1960-89); 32/70mm (1977-89)
Teldec-Press GmbH, Nortorf, Germany [Manufactured in Germany]                                           29-32/70mm (1960-89); 29-32mm (1951-65); 32/70mm (1977-89)
Cinram, Scarborough, ON (Canada) [(CR), CR, CI, 230]                                                                   29-69mm or 26/77mm muffin. 1969-1981
Alshire Custom Products, Burbank, CA (Alshire, AL)                                                                        29-70mm (1976-91); 73mm (1974-77); 31.7mm (1978-79) [Pablo]
CBS/Columbia Internacional, S.A., Mexico City                                                                                 29/70mm (faint muffin top) [1968 - ?]
CBS, Haarlem, The Netherlands (XX-XXXXX-XX)                                                                                29/70mm (1971-1990) [CBS, SteepleChase 08) became Sony/CBS in 1991
Diskmakers [Philadelphia, NYC, Chicago] [DM, TV ◅ Ʃ, ᗡᕒ]                                                      29/70mm (1979-88); 68-74mm (1961-62); 70mm (1961-74); 29mm (1975-77)
Memphis Record Pressing, Memphis, TN (MRP, [MRP-XXXXX)                                                     29/70mm (2015-17); 32mm (2017-present); 32/70mm (2018-20)
PRC West, Compton, CA [PRC-C, PRC-W, 26]                                                                                      29/70mm (muffin top) [1975-1984]
Precision Record Pressing, Inc., Nashville, TN [PRP-XXXX]                                                            29/70mm [1961-76] limited-run, local pressings
QCA Custom Pressing, Cincinatti, OH (QCA)                                                                                     29/70mm (1977-90); 73mm (1966-72); 29mm (1969-87); 29/88mm (1984-92)
Record Industry, Haarlem, The Netherlands (XXXXX 1A)                                                               29/70mm or 29mm; (1998-present). [Sony, EMI, Music on Vinyl]
Sony/CBS, Haarlem, The Netherlands (XX-XXXXX-XX)                                                                     29/70mm (1991-1998) bought by Record Industry in 1998
Third Man Pressing, Detroit, MI [TMP, concentric circles in label]                                              29/70mm (2017-18), 32mm (2018-present) [2017-present]
United Record Pressing, Nashville, TN (u) (U)                                                                                    29/70mm or 33/70mm (1972-present)
QCA Custom Pressing, Cincinatti, OH (QCA) (1966-92)                                                                    29/88mm (1984-92); 29/70mm (1977-90); 73mm (1966-72); 29mm (1969-87)

 

Alshire Custom Products, Burbank, CA (Alshire, AL)                                                                        30mm or 31.7mm, some w/ 88mm chamfered edge, (1990 only) (concentric rings)
Capitol Records-EMI Of Canada Limited, Ontario, CA                                                                     30mm [stamped Capitol logo] (1947-present)
Deutsche Grammophon, Phonodisc GmbH, Hannover, Germany [320]                                       30mm, (1951-66); 28-30mm (1961-72); 19/80mm (1971-72) [DG, Philips, Polydor]
Electrecord, Bucharest, Romania                                                                                                          30mm [1932-present] some 29-31mm deep groove
Musikkindustri A/S, Oslo, Norway [710, F, FE, EE, IHJ, TA, SS, P YR]                                            30mm (w/ 5mm raised outer ridge) (1967-83) [CBS, PolyGram, EMI, Steeplechase]
Phonodisc Ltd, London, UK [// x ▽420, 1 1 1]                                                                                    30mm (1969-79); 33mm (1970-3); 30/88mm (1970-73) [Polydor, ATCO, MGM]
Polydor K.K., Japan                                                                                                                                  30mm (40mm shadow ring; 80mm chamfered edge) (1971-99) [Japanese Verve]
Polydor Ltd. UK                                                                                                                                          30mm
Unknown French pressing (Barclay 1972)                                                                                            30/34/86mm triple ring
Fonobras, Distribuidora Fonografica Brasileira LTDA, Brazil                                                         30/39/85mm (EMI/Polygram) [1985-present]
Gotta Groove Records, Cleveland, OH                                                                                                   30/72mm (2009-present, presses bought from Sun Plastics)
C.I.D.I.S. Louviers, France (Philips) [380]                                                                                             30/88mm (1969-1978) (Sister plant in Antony, France 1972-78)
COFASA, Madrid, Spain (850)                                                                                                                  30/88mm [1970-1983] before see Fonogram, after see Polydor
Eurogram, S.A., Madrid, Spain (850)                                                                                                     30/88 [1988-?] before see Fonogram, Cofasa, Polygram
Fonogram, S.A., Madrid Spain (850)                                                                                                      30/88 (1962-70] after see Cofasa, Polygram, Eurogram
Musikkindustri A/S, Oslo, Norway [710, F, FE, EE, IHJ, TA, SS, P YR]                                             30/88mm (5mm raised outer ridge) (1967-83) [CBS, PolyGram, EMI, Steeplechase]
Phonodisc B.V., Baarn, The Netherlands [670]                                                                                   30/88mm (1966-1980), 22-24mm (1962-66) (EMI, PolyGram, CBS, Steeplechase]
PolyGram Servicios, S.A., Madrid, Spain (850)                                                                                    30/88 (07/1983-1988) before see Cofasa and Fonogram
PolyGram Records, LTD, Wellington, New Zealand                                                                            30/88 [Philips, PhonoGram, Universal Music] 1970-1999
PRS Baarn, The Netherlands [670]                                                                                                          30/88mm (1980-1993)
PhonoComp, Tribiano, Italy (520, PC)                                                                                                    30/88mm (1985-99) Previously: Phonoster 1968-85)

Phonoster, Tribiano, Italy (520)                                                                                                               30/88mm (1968-85) Renamed: PhonoComp (1985-99)

Alshire Custom Products, Burbank, CA (Alshire)                                                                                31/68mm muffin top (?), [closed in the 90s] (Pablo)
Alshire Custom Products, Burbank, CA (Alshire)                                                                                31/88mm w/con. rings [88 ring is smooth] Pablo [closed 90s]
Presswell Records, Ancora, NJ (PR) (1958-90)                                                                                      31/70mm or 32/70mm (1960-1973); 35/70mm (1968-84); (last LP pressed - 1984)
PolyGram Record Services Ltd., London [▽ 420]                                                                                31/82mm [2/79 to mid 1988] [Philips]

Alshire Custom Products, Burbank, CA (Alshire, AL)                                                                          31.7mm (1978-79); 29-70mm (1976-91); 73mm (1974-77) [Pablo]
Rainbo Records, Santa Monica, CA [S-XXXX]                                                                                        31.7mm (1976-2006) [often with 11mm inner ring on one or both sides]
Rainbo Records, Santa Monica, CA [S-XXXXX]                                                                                      31.7/70mm (1979-2006) [muffin often with 11mm inner ring on one or both sides]
Rainbo Records, Canoga Park, CA [S-XXXXX]                                                                                        31.7/70mm (2006-2019) [muffin often with 11mm inner ring on one or both sides]
Rainbo Records, Santa Monica, CA [S-XXXXX]                                                                                      72mm (1966-76) generally for budget, one-color labels

Record Technology Incorporated, Camarillo, CA [XXXXX.1(3)]                                                        31.7mm or 31.7/70mm (1977-present) [Concord]
H.V. Waddell, Burbank, CA [W, WC]                                                                                                        31.7mm 1976-1984 (see Waddell below) [Verve, MGM, London, Derem, Arista]

 

Rainbo or RTI or Waddell?  From 1976/77 to 1984, all three plants pressed with a 31.7mm ring.  Other than the known W or WC plant markings for Waddell or S-XXXXX matrix codes on Rainbo and XXXXX.1(3) on RTI, Rainbos often have an 11mm inner ring on one or both sides.  Rainbo pressing rings tend to be sloppier, less crisp than RTI or Waddell.  RTI tend to have light concentric rings in the label. Waddell mainly pressed only for its big clients, Verve, MGM, Arista, London, and subsidiaries.

Rainbo or RTI? From about 1979-2020, Rainbo and RTI both used a 31.7/70mm pressing ring.  A sure way to tell them apart is the matrix code:  Rainbo’s matrix is S-XXXXX, while RTI uses an XXXXX.1(3) matrix.  However, they are not always present.  If there is no matrix code some indicators are:  In general, Rainbo’s 31.7mm ring is less clean.  Rainbos often have an 11mm inner ring on one or both sides.  RTI muffin top is slightly more pronounced. Rainbo tended to press for more popularly-priced and smaller labels.  Since about 2010, RTI has catered more to high end, audiophile 180-gram pressings.  In general, RTI tends to press audiophile labels with 31.7mm and larger runs with 31.7/70mm.  

Allied Records, Ltd., London [(ALI)]                                                                                                        32mm (1959-72; 28-30mm or 29-32mm (1961-77); 32/70mm (1962-82)
Aprelevsky Order of Lenin Record Plant, USSR                                                                                    32mm [Melodya]
AREACEM. Tourouvre, France [a AREACEM]                                                                                          32mm (inward sloping ring) (1971-80) Name changed to SNA Sept. 1980.
Ariola Eurodisc GmbH, Munich Germany                                                                                               32mm
Century Record Mfg. Co. [V-#####, FV-#####, FPV-#####, FP V-#####]                          32mm (1973-90); 68-72mm (1952-61); 73mm (1961-73)

Dublin Vinyl, Dublin, Ireland [DV]                                                                                                           32mm (2017-present]
Dureco Fabriek (Dutch Record Company), Naarden, NL                                                                    32mm (1952-1998)
EMI ITALIANA S.p.A., Varese, Italy (DA-MO-YR)                                                                                    32mm (1967-present)
EMI Music France (Paris, France)                                                                                                             32mm (1990-2013) [formerly Pathé Marconi EMI]

Furnace Recording Pressing, Alexandria, VA [FRP, FURNACE]                                                         32mm (2018-present)
Hand Drawn Pressing. Addison, TX [HDP ####]                                                                                32mm (2017-present)
His Master's Voice Limited, Wellington, NZ                                                                                         32mm (1962-73); 29-32mm (1954-1972)
Interpress, Hamburg, Germany [IP, I.P.]                                                                                                32mm (1976-95) [some with 40mm shadow ring] Owned by Bellaphon.
Les Industries Musicales Et Electriques Pathé Marconi                                                                    32mm (1964-1972) [renamed Pathé Marconi, 1972]
EMI (New Zealand) Limited, Auckland, NZ                                                                                            32mm (1972-present), previously His Master’s Voice (1954-1972)
Gold Rush Vinyl Llc, Austin, TX [GRV]                                                                                                      32mm (2019-present)
gzvinyl.com, Lodenice, Czech Republic [before 2014]                                                                         32mm (2000-2013) [E1/A and E2/B in matrix]
GZ Media, Lodenice, Czech Republic [starting 2014)                                                                          32mm (2014-present) [E1/A and E2/B in matrix]
Memphis Record Pressing, Memphis, TN (MRP, [MRP-XXXXX)                                                        32mm (2017-present); 29/70mm (2015-17); 32/70mm (2018-present)
MGM Records Bloomfield, NJ ["S" ankh, sailor's cap, arrow]                                                           32mm (1959-71); 70-74mm deep groove (1950-61); [MGM, Verve]
MPO Moulages et Plastiques de l’Ouest, Averton, France [MPO, MP]                                           32mm (1965-present); 15/24/32mm (1983-present); [68-70mm & 66-70mm rare in 1960s]
Optimal Media GmbH, Robel/Muritz, Germany                                                                                   32mm [BY XXXXX, B=LP, Y = the year A=2010, F=2015, K=2020) (1, +, >)
Palomino Records, Shepherdsville, KY                                                                                                   32mm [2012-present]
Pathé Marconi EMI (Paris, France)                                                                                                          32mm (1972-1990) [renamed EMI Music France 1990-2013]
P.R. Records Ltd., Harrogate (CD, CED, P, CT, D, E, G, M, P, R, T, PAG)                                            32mm (1980-2001); 22/33mm (1979-96); 35/65mm (1990-92) (Jasmine, Rhapsody)
Precision Record Pressing, Burlington, Ontario [10-XXXXX]                                                            32mm (2017-present) joint venture with GZ Vinyl, “Made in Canada” sticker   
Quality Record Pressings (Salina, KS) [QRP]                                                                                         32mm (2022-present); 32/70mm (2011-present); 70mm (2011-12)

SNA, Tourouvre, France [SNA stamp or etch]                                                                                        32mm; 32/70mm (inward sloping ring) [1980-2018] Bought by GZ Media in 2018.   
Standard Vinyl, Victoria, BC, Canada [Standard, SV, V-#######]                                                32mm (2014-present)       
The Vinyl Factory, London, UK                                                                                                                  32mm (2001-present) Specializes in limited-edition runs
Third Man Pressing, Detroit, MI [TMP, concentric circles in label]                                                 32mm (2018-present); 29/70mm (2017-18); [2017-present]
Victor Company Of Japan, Ltd. Yokohama [111, 112, 132, 311, 312]                                               32mm or 32/44mm or 32/44/90mm or 32/90mm [1927-present] [RCA, early MFSL]
Warner Music Mfg. Europe GmbH, Alsdorf, Germany                                                                        32mm (1990-2003] (Before 1990 - Record Service GmbH)
Victor Company Of Japan, Ltd. Yokohama [111, 112, 132, 311, 312]                                               32/44mm or 32mm or 32/90mm [1927-present] [RCA, East Wind, early MFSL]
Unknown Japanese plant                                                                                                                            32/45mm [Verve 23MJ 3394, 1984]
CBS Pressing Plant, Aston Clinton, Buckinghamshire, UK                                                                 32/63mm (1964-1980)
Brooklyn Phono, Brooklyn, NY (brooklynphono)                                                                                 32/64mm [2003-present]
Allied Records, Ltd., London [(ALI)]                                                                                                         32/70mm (1962-82); 28-30mm or 29-32mm (1961-77); 32mm (1959-72)
Memphis Record Pressing, Memphis, TN (MRP, [MRP-XXXXX)                                                         32/70mm (2018-20); 32mm (2017-present); 29/70mm (2015-17)
Presswell Records, Ancora, NJ (PR) (1958-90)                                                                                        32/70mm or 31/70mm (1960-1973); 35/70mm (1968-84); (last LP pressed - 1984)
Quality Record Pressings (Salina, KS) [QRP]                                                                                          32/70mm (2011-present); 32mm (2022-present); 70mm (2011-12) 

SNA, Tourouvre, France [SNA stamp or etch]                                                                                          32/70mm; 32mm (inward sloping ring) [1980-present] Bought by GZ Media in 2018
Teldec-Press GmbH, Nortorf, Germany [Manufactured in Germany]                                                32/70mm (1977-89); 29-32/70mm (1960-89); 29-32mm (1951-65)
Sonopress, Gütersloh, Germany                                                                                                                 32/73mm [1957-present] (###### A-1/YR S) (Made in Germany)
Alshire Custom Products, Burbank, CA (Alshire)                                                                                    32mm w/ 88mm chamfered edge, (1975-1999) [Pablo]
Victor Company Of Japan, Ltd. Yokohama [111, 112, 132, 311, 312]                                                32/90mm or 32mm or 32/44mm [1927-present] [RCA, East Wind, early MFSL]
Adrenalin Records, Ltd., Slough, UK (Adrenalin)                                                                                   33mm [1986-1998]
Celebrate Records GmbH, Stolberg, Germany                                                                                        33mm [2002-present] [XXXXXXX A1 KM (later is masterer initials)]
Columbia (pressed by EMI Italiana S.p.A. (Milan, Italy)                                                                      33mm
Decca Records, New Maiden, UK [ZAL, EAL, ARL)                                                                          33mm (1959-80); 69-72mm (1959-68); 19/69-72mm (1958-68); 25mm (1952-58); 19/95-97mm (1957-59)

RCA Record Factory, Rome, Italy                                                                                                               33mm [a few seen, but mostly 26mm]
Hungaroton (Hungary)                                                                                                                                33mm
Independent Record Pressing, Bordentown, NJ [IRP]                                                                          33mm [IRP] [2015 - present]
Melodya Records, USSR                                                                                                                                33mm
MY45, Tiefenbach, Germany [MY45, XX@MY45 xx=masterer]                                                           33mm (2006-present) First LPs in 2017 (Stockfisch, in-akustic)
New Orleans Record Pressing, New Orleans, LA                                                                                    33mm (2018-present)
(Pallas) Schallplattenfabrik Pallas GmbH, Diepholz, Germany                                                          33mm; 33/60mm; 33/60/80mm; [concentric rings in label) -XXXXX-
Pathé Marconi EMI, France (EMI France)                                                                                                 33mm [Blue Note 1983-87]
Phonogram Records Pty. Ltd. Australia                                                                                                    33mm [Polygram]
TELDEC Record Service GmbH, Alsdorf, Germany                                                                                 33mm (1988-98) [Alsdorf bought by Teldec in 1988]
Wakefield Manufacturing, Phoenix, AZ (tulip stamp, WM-XXXXX)                                                  33mm (1964-74); 33/70mm (1980-89); 73mm (1963-64)
Memphis Record Pressing, Memphis, TN (MRP) (2014-present)                                                        33/70mm, 32mm [MRP-XXXXX] (bought by gzvinyl in 2015)
TELDEC [Telefunken-Decca] Schallplatten GmbH, Hamberg, Germany                                            33/70mm 1950-1983 [renamed TELDEC Schallplatten GmbH in 1983]
RCA Schallplatten GmbH, Hamburg, Germany                                                                                        33/70mm

 

Wakefield Manufacturing, Phoenix, AZ (tulip stamp, W over M stamp) (1963-89)                     33mm; 34/63mm; 33/70mm; 33/72mm; 33/84mm pudding top
1963-64         73mm
1964-74         33mm [outside edge has satin look]
1980-1989     33/70mm muffin top with large slope. 43mm or 46mm "shadow" ring around inner ring

Wakefield Manufacturing, Phoenix, AZ (WM stamp, tulip stamp)                                                    33.3/70mm (some 98mm chamfer) or 70mm [#####-A] (1980-89) [Blue Note]
Memphis Record Pressing, Memphis, TN (MRP)                                                                                     33/70 [MRP-XXXXX] (2014-presesnt) (bought by gzvinyl in 2015)
Record Service GmbH, Alsdorf, Germany (R/S)                                                                                        33/70mm [1975-1988] [bought by TELDEC in 1988]
Wakefield Manufacturing, Phoenix, AZ (tulip stamp, WM-XXXXX, Mo#2)                                      33/70mm (1980-89); 73mm (1963-64); 33mm (1964-74)
Iberofon, S.A., Madrid, Spain [#N#]                                                                                                          33/88mm [#N# or #N#DM/DMI/DMM] (1959-2014)
Allied Record Company, Los Angeles, CA (AR, EAST, B-#####, 22)                                                   35mm (1976-83, rare); 26mm (1975-81); 35/70mm (1982-89); 73mm (1971-75)

Artist's Recording Company, Cincinnati, OH [ARC YRMO##, **YRMO##]                                       35mm (1974-85); 72mm (1969-75); 35-70mm (1975-85) [religious music]
ElectroSound Group Midwest, Shelbyville, IN (EMW, B, 016)                                                              35mm (1978-87); 35/75mm (1980-88); 35/70mm (1980-88); 35/73mm (1978-91)
Europadisk, NYC [(EDP), Europadisk DMM]                                                                                            35mm (1981-2004) 35/52mm (1981-83); 28mm (1985-2004)
King Record Co., Tokyo, Japan                                                                                                                    35mm (45mm shadow ring) [East World]
Toshiba EMI LTD Tokyo, Japan                                                                                                                    35mm [1973-94] [45mm slight muffin]
King Record Company, LTD. (Tokyo, Japan)                                                                                            35/40mm, 34/44mm [1951- ] (Blue Note, A&M, CTI)
Turicaphon AG, Zurich, Switzerland [TU, Ⓣ]                                                                                            33/50mm (or 33/65mm) [1931-1992] GRP, EMI, Polydor, Ex Libris
Europadisk, NYC [(EDP), Europadisk DMM]                                                                                            35/52mm (1981-83); 28mm (1985-2004); 35mm (1981-2004)
Damont Audio, Hays, Middlesex, UK (DAMONT)                                                                                    35/58mm or 35/61mm (shadow ring at 45mm)

Allied Record Company, Los Angeles, CA (AR, EAST, B-#####, 22)                                            35/70mm (1982-89); 26mm (1975-81). Rare: 35mm (1976-83), 73mm (1971-75)

NB: Check carefully for "E A S T" around the spindle hole (after 1979) = Pressed by Specialty Record Comp. from plates originally made for Allied. A lone "A" embossed in the label area indicates it was pressed at Allied. From 1982-89, Specialty has the same 35/70mm ring, but the outer is more pronounced.
 

Artist's Recording Company, Cincinnati, OH [ARC YRMO##, **YRMO##]                                      35-70mm (1975-85); 35mm (1974-85); 72mm (1969-75); [religious music]

Cascade Record Pressing, Milwaukie, OR [CP## - ####]                                                                    35/70mm muffin [2014-present]

Donora Mfg. Co. Inc., Holtsville, LI, NY [Donora]                                                                                   35/70mm (1977-79); [Inner City, MMO Music Group]

Hauppauge Record Mfg, (HRM, double arrow, pennant with dot)                                                    35/70mm [1981-1989] [<1981 was named Keel] [Hauppauge, LI, NY]
Hub - Servall Record Mfg. Corp., Cranbury, NJ (HUB, HuB)                                                                35/70mm [muffin top, 10mm inner ring side 1] (1975-2007)
Keel Mfg, Hauppauge, NY [K, pennant, union jack, 53, notched edge]                                            35/70mm 1979-81; 70mm 1961-79 [11mm inner]; sold to Hauppauge ‘81
Mercury Record Manufacturing Co., Richmond, IN                                                                                35/70mm [after 1977]
Monarch Record Mfg. Co., LA [MO, (MR), △ XXXXX]                                                                            35/70mm from 1976-85 [before, 70 or 73mm]
PRC Recording Company, Richmond, IN (RI, 72, PR, PRC-R, PH)                                                        35-70mm or 35/73mm (1975-90); 70mm 1972-77, overlap from (1975-77)
Plastic Products Company, Memphis, TN [PP]                                                                                        29/70mm (70mm) 1949-1978 [Atlantic, Sun, MGM, Chess, ABC, Scepter]
P.R. Records Ltd., Harrogate (CD, CED, P, CT, D, E, G, M, P, R, T, PAG)                                                35/65mm (1990-92) 22/33mm (1979-96); 32mm (1980-2001); (Jasmine, Rhapsody)
Presswell Records, Ancora, NJ (PR) (1958-90)                                                                                            35/70mm (1968-84); 32/70mm (1960-1973); (last LP pressed - 1984)
Sound Makers Records Mfg. Co. Westville, NJ [SMK, SMI, 60, ✩]                                                        35/70mm [muffin, 10mm inner ring side 1] (1977-86) [Applause]

Specialty Record Corporation, Olyphant, PA (SP, SRC, E A S T, 49)                                                 35/70mm 1970-98; 69-71mm 1959-62 (rare); 70mm 1963-74; 38mm 1968-69
 "E A S T" around the center hole beginning in 1979 = Pressed by SRC from metal parts that were originally made for Allied Record Company. Los Angeles (SRC’s sister company (bought by Warners) in 1979).  A lone "A" embossed in the label area would indicate it was pressed at Allied Record Company. Specialty pressed LPs from approximately 1959-98. Before 1968, mostly small-time job lots.  First big contract was Atlantic in 1968, then Elektra in 1970, and Reprise in 1973.  Vast majority of Specialty pressings are 35/70mm.

Superior Record Pressing Corp., Somerdale, NJ [SRPC around spindle]                                            35/70mm (1972-85); 70mm 1968-72
Superior Record Pressing Corp., Tempe, Arizona [SRPCW]                                                                    35/70mm [1979-1991]

 

ElectroSound Group Midwest, Shelbyville, IN (EMW, B, 016)                                                                35/70mm (1980-88); 35/73mm (1978-91); 35/75mm (1980-88); 35mm (1978-87)
ElectroSound Group Midwest, Shelbyville, IN (EMW, B, 016)                                                                35/73mm (1978-91); 35/70mm (1980-88); 35/75mm (1980-88); 35mm (1978-87)
ElectroSound Group Midwest, Shelbyville, IN (EMW, B, 016)                                                                35/75mm (1980-88); 35/70mm (1980-88); 35/73mm (1978-91); 35mm (1978-87)
 

PRC Recording Company, Richmond, IN (RI, 72, PR, PRC, PH)                                                               35-70mm or 35/73mm (1974-1990) (1972-1974 ring was 70mm)
Burlington Record Plant, Burlington, VT [BRP XXX YEAR]                                                                     37/70mm muffin top; (2015-present) [low volume, boutique press]
Specialty Record Corporation, Olyphant, PA (SP, SRC, E A S T, 49)                                                        38mm 1968-69; 35/70mm 1970-98; 70mm 1963-70; 69-71mm 1959-62 (rare)

Capitol Records

Capitol Records, Jacksonville, IL [JW ,0]                                                                                                     38mm 1965-87
Capitol Records, Los Angeles (LW, ☆, ✲, *)                                                                                               39.5mm 1947-88 (some w/ 13mm inner ring on side 2)
Capitol Records, Scranton, PA [anvil, IAM in triangle]                                                                             38mm 1946-73 [anvil stamp until 1964, then IAM in triangle until ‘73]
Capitol Records, Winchester, VA [WW, ----<]                                                                                               35.5mm or 36mm [13mm inner ring on side 2] 1968-86
 

Capitol Notes:  On a white background, Jacksonville LPs have a slightly burnt beige tint to them. Whites are “whiter” on L.A. and Winchester labels.  By 1975, all Capitol lacquers were cut in Los Angeles at Capitol Mastering and sent out to the various plants. So “JW" or “WW” isn't a guarantee they were pressed in Jacksonville or Winchester; it just means the lacquers were sent there originally.  Where they ended up might be somewhere different (which is why you see Winchester pressings with -LW lacquers, Jacksonville pressings with WW lacquers, etc.]

 

North American Musical Industries, Pittsburgh, PA [anvil stamp]                                     39mm (from Nov. 1973-80 bought Capitol Scranton in '73

H.V. Waddell Co. - Burbank, CA (W or WC)                                                                             68-70mm [1959-68] (Blue Note/Liberty, MGM, Verve west coast)
Plastylite, North Planfield, NJ (cursive "P" stamp)                                                               68-70mm (1949-66) [also 69-71, 70-72] (all Blue Note up to 1966)

Plastic Products Company, Memphis, TN [PL, PP] (1959-1979)                                            68-70.5mm deep groove from [1959-61 only]; (29/70mm or 70mm 1960-79)
Abbey Record Manufacturing Comp. East Newark, NJ [AB MO-YR, (A)]                              68-72mm [some w/ 21mm inner side B] (1955-63) 70mm [1962-70] [Prestige]

Century Record Mfg. Co. [V-#####, FV-#####, FPV, FP V]                                                      68-72mm (1952-61); 73mm (1961-69); 32mm (1973-90)
CBS Records Canada, Ltd. Don Mills, Toronto [DM, HZ, HDZ, CRC]                                      69mm [1971-88] Trademark owner is Epic

Columbia Records had a 69-71 deep groove on all pressings until CL 1645 (plus or minus) in 1961. All plants were changed over to the 69mm normal or “ledge” groove in summer/fall of 1961. There are no deep groove pressings from Santa Maria or Carrollton, and only a small number from Pitman.  Columbia's NYC mastering studio used a ☆ in the matrix (just like Capitol's) from 1956-57, found on Bridgeport and Hollywood pressings only.

 

Columbia Pressing Plant, Bridgeport, CT (CLB, BP, --, . .)                                                    69-71mm 1923-1961; 69mm 1961-64 [extra leading in album and track titles]
Columbia Pressing Plant, Carrollton, GA [G1]                                                                       69mm [with a faint 11mm inner ring] 1981-91; no deep grooves
Columbia Pressing Plant, Hollywood, CA (H)                                                                        69-71mm 1935-1961 (CL 1645); 69mm 1961-64
Columbia Pressing Plant, Pitman, NJ (P, CP, 54)                                                                    69mm [1960-1988] limited deep grooves (opened 10/60)
Columbia Pressing Plant, Santa Maria, CA (S, Ƨ, CSM)                                                          69mm [1963-1981 no deep grooves; slight concave/convex cupping at spindle
Columbia Pressing Plant, Terre Haute, IN (CT, CTH, T)                                                          69-71mm DG [1953-61 (CL 1646) 69mm 1961-82

Columbia Indicators:

 

☆ = Mastered at Columbia Studios, NYC between 1956-57.  Appears only on mono six-eye pressings from Bridgeport or Hollywood.

BP, CLB .. , extra leading in title = Pressed by Bridgeport
G1 = Pressed by Carrollton
H = Pressed by Hollywood
P or CP or CRP = Pressed by Pitman
S or S1 or S2 or Ƨ or CSM = Pressed by Santa Maria
T or T1 or T2 or CT or CTH = Pressed by Terre Haute
PN = (very rare) Mastered At Pitman, Pressed By NAMI (a non-Columbia plant in Scranton)
PXS = Plated by Pitman and Pressed by Santa Maria.
SX = Plated and pressed by Santa Maria
SXT = Plated at Santa Maria and pressed by Terre Haute
SXP or SX(P) = Plated at Santa Maria and pressed by Pitman
TX = Plated and pressed by Terre Haute

TXG = Plated at Terre Haute and pressed by Carrollton

 

CBS – Discos Naucalpan, Mexico                                                                                            69mm [1963-68]
Hispavox S.A., Madrid, Spain                                                                                                   69mm deep groove [1953-1985]
WEA Records Pty. Limited, Sidney, Australia                                                                         69mm (light 88mm muffin] MX1-XXXXX (1970-present)

 

Specialty Record Corporation, Olyphant, PA (SP, SRC, E A S T, 49)                                       69-71mm 1959-62 (rare); 70mm 1963-70; 38mm 1968-69; 35/70mm 1970-98
RCA Records, Hollywood, CA (H)                                                                                             69-70.5mm DG 1941-1968/70 [25.5mm 1968/70-76]
RCA Records, Indianapolis, IN (I)                                                                                            69-70.5mm DG 1939-1969/70 [25.5mm 1968/70-87]
RCA Records, Rockaway, NJ (R)                                                                                                69-70.5mm DG 1954-1969/70 [25.5mm 1968/70-73]

RCA Records, Smiths Falls, Ontario, CA [ACR, AcR, GT]                                                                               69-70.5mm (1954-71); 69-73mm [varies from 71 to 73] (1952-70);  25.5mm (1971-81)

Decca Records, New Maiden, UK [ZAL, EAL,                                                                                  69-72mm (1959-68); 33mm (1959-80); 19/69-72mm (1958-68); 25mm (1952-58); 19/95-97mm (1957-59)
American Record Pressing, Owosso, MI [ARP]                                                                        69-71mm deep groove (1959-69); 70mm 1968-1972; [Buddah, Vee-Jay]
 

Richmond, IN (All the same plant, check dates for ownership)
Decca Records, Richmond, IN [3, ★, ◈]                                                                                  69-71mm DG (some 71-73mm seen) deep groove [1939-57]

RCA Records, Smiths Falls, Ontario, CA [ACR, AcR, GT]                                                                               69-73mm [varies from 71 to 73] (1952-70); 69-70.5mm (1954-71); 25.5mm (1971-81)
National Record Pressing, Inc., Richmond, IN                                                                        70-74mm DG [05/1958-09/1961]
Richmond Record Pressing, Inc., Richmond, IN (R, RR, MR, RFR)                                          69-71mm DG [09/1961-66] (owned by Mercury)
Mercury Record Manufacturing Co., Richmond, IN (MR, RR)                                                 70mm [1966-69] 69-71mm DG 1966-1967
Philips Recording Company (PRC), Richmond, IN (RI, 72, PR, PRC, PH)                                70mm [1970-72]
PRC Recording Company, Richmond, IN (RI, 72, PR, PRC-R, PH)                                            70mm [1972-77]; 35/70mm [1973-90] (some 35/73mm seen)
PRC Recording Company, Richmond, IN (RI, 72, PR, PRC, PRC-R, PH)                                    35/70mm [1973-90]; 70mm [1972-77] (some 35/73mm seen)

Abbey Record Manufacturing Comp. East Newark, NJ [AB MO-YR, (A)]                                70mm (1961-70); 68-72mm [some w/ 21mm inner side B] (1955-62) [Prestige]
ABC - True Sound Manufacturing Corp. Hauppauge, NY (TSM, TƧM)                                    70mm (ABC's east coast plant) est. 1965 (ABC, Impulse)
All Disc Records (Liberty/UA East Coast) Roselle, NJ                                                            70mm [1960-1981] [22, 33, 44, 66, 77, 114, AD, ALL DISC, N-47]
Allentown Record Co. Inc., Allentown, NJ [ARC, AL, ALT]                                                        70mm [1947-1984] [AL w/date xx-xx-xx] [Kapp, Elektra, VOX]
American Record Pressing, Owosso, MI [ARP]                                                                        70mm (1968-1972); 69-71mm deep groove (1959-69); [Buddah, Vee-Jay]
Audio Manufacturing Record Co. [Lakewood, NJ] [AL]                                                           70mm (1967-1975); [London, Phase 4]
Bestway Products, Mountainside, NJ (B, Bestway, BG, BW, B/W)                                         70mm (1950-1986)
Connoisseur Record Corp., Kearny, New Jersey                                                                     70mm [pressed Roulette Records and subsidiaries]
Diskmakers [Philadelphia, NYC, Chicago] [DM, TV ◅ Ʃ, ᗡᕒ]                                                70mm (1961-74); 29/70mm (1979-88); 68-74mm (1961-62); 29mm (1975-77)
Goldisc Recording Products, Inc. Holbrook, Long Island, NY (GOL)                                     70mm 1975-83 [From 1960-1975, called Sonic Recording Products]

Keel Mfg, Hauppauge, NY [K, pennant, union jack, 53, notched edge]                                70mm (1961-79); 35/70mm [11mm inner]; sold to Hauppauge ‘81
Monarch Pressing Plant, LA, CA (MO, MR, △ XXXXX)                                                              70mm or 73mm 1955-1978 [35/70mm from 1976-85]
Plastic Products Company, Memphis, TN [PP] (1959-79)                                                        70mm (1962-80); (68-70.5mm DG 1959-61) [ABC, Atlantic, Sun, MGM, Chess,)
Premier Custom Pressing, Clifton, NJ [☆]                                                                               70mm [five-pointed star 1962 - ca. 1972]
RCA Records, Smiths Falls, Ontario, Canada (ACR, AcR, GT)                                                  70mm [1954-1979]; 69-70.5 (1954-73);  (also 26mm) GT = Mastered RCA Toronto
Philips Recording Company (PRC), Richmond, IN (RI, 72, PR, PRC, PH)                                70mm [1970-72]
PRC Recording Company, Richmond, IN (RI, 72, PR, PRC-R, PH)                                            70mm (1972-77) changed to 35-70mm starting in 1975 (overlap 1975-77)
Quality Record Pressings (Salina, KS) [QRP]                                                                                                  70mm (2011-12); 32/70mm (2011-present); 32mm (2022-present)

Shelley Products, Huntington Station, LI, NY [X, LY, 54, SH, S, Ƨ]                                          70mm (1969-85) vinyl; 19mm (1947-1985) styrene; label diameter: 98mm
Sonic Recording Products, Holbrook, NY [SON, sonic, K-XXXX]                                            70mm 1960-75 [From 1975-1983, renamed Goldisc Recording Products]
Springboard Custom Pressing, Rahway, NJ [SLX-####, SLT-####]                                         70mm 1976-79 [Catalyst, Springboard, Trip, UpFront, Buckboard labels]

True Sound Manufacturing Corp. Hauppauge, NY (TSM, TƧM)                                              70mm (ABC's east coast plant) est. 1965 (ABC, Impulse)
Wakefield Manufacturing, Phoenix, AZ (WM stamp, tulip stamp)                                        70mm [Flying Fish]
Southern Plastics, Memphis, TN (SO-XXXX)                                                                            70mm [Became United Record Pressing in 1971] [Atco]
Specialty Record Corporation, Olyphant, PA (SP, SRC, E A S T, 49)                                        70mm 1963-74; 35/70mm 1970-98; 38mm 1968-69; 69-71mm 1959-62 (rare)
Superior Record Pressing Corp., Somerdale, NJ [SRPC around spindle]                              70mm 1968-72; 35/70mm (1972-85)
UA/Liberty East Coast [All Disc Records, Roselle, NJ]                                                            70mm [22, 33, 44, 66, 77, 114, AD, ALL DISC, N-47]
True Sound Manufacturing Corp. (ABC) [TSM]                                                                        70mm [Hauppauge, Long Island, NY]
H.V. Waddell Co. – Burbank, CA (W or WC)                                                                               70-72mm [1967-1977] [west coast MGM, Verve]
MGM Records Bloomfield, NJ ["S" ankh, sailor's cap, arrow]                                                 70-74mm deep groove (1950-61); 32mm (1959-71) [MGM, Verve]
National Record Pressing, Richmond, IN [see Richmond above]                                          70-74mm deep groove (1958-61); [owned by Mercury Records]
Columbia Pressing Plant, Bridgeport, CT (CLB or BP or --)                                                    71mm [1923-1964]

Artist's Recording Company, Cincinnati, OH [ARC YRMO##, **YRMO##]                                             72mm (1969-75); 35-70mm (1975-85); 35mm (1974-85); [religious music]
Rainbo Records, Santa Monica, CA [S-XXXX]                                                                           72mm (1966-76) [generally one-color, budget pressings]; 31.7mm
Allied Record Company, Los Angeles, CA (AR, EAST, B-#####, 22)                                          73mm (1971-75, rare); 26mm (1975-81); 35/70mm (1982-89); 35mm (1976-83)
Alshire Custom Products, Burbank, CA (Alshire, AL)                                                               73mm (1974-77); 29-70mm (1976-91); 31.7mm (1978-79) [Pablo]
Apex Record Corporation Hollywood, CA                                                                                 73mm (1961-66) [SM sig in runout] (Charlie Parker Records)

Century Record Mfg. Co. [V-#####, FV-#####, FPV, FP V]                                                         73mm (1961-73); 68-72mm (1952-61); 32mm (1973-90)

Fidelatone, Hawthorne, CA [ƒį, FT, FI, F, Ⓕ]                                                                               73mm (1970-81) [Atlantic label = FT]
H.V. Waddell Co. – Burbank, CA (W or WC)                                                                                73mm [1967-1977]; 31.7mm (1977-82); 68-74 (1956-59); 68-70mm (1959-68)
H.V. Waddell Co. - Burbank, CA (W or WC)                                                                                 72/92mm [1967-1970]
Custom Fidelity Records, Hollywood, CA                                                                                   73mm [Concord Jazz]
Custom Record Manufacturing, Los Angeles, CA                                                                      73mm [Crown, Modern, Kent, RPM [NB: Custom had 3.5" label]
Monarch Record Mfg. Co., LA [MO, (MR), △ XXXXX]                                                                   73mm or 70 1955-1978 [35/70mm 1976-85]
QCA Custom Pressing, Cincinatti, OH (QCA) (1966-92)                                                              73mm (1966-72); 29mm (1969-87); 29/70mm (1977-90); 29/88mm (1984-92)
Rainbo Records for Capitol Records                                                                                           73mm
Research Craft (UA/Liberty West Coast, Los Angeles, CA] [R, Re,]                                           73mm [1945-1981] [Liberty-1965-71; UA-1971-78; Capitol-1978-81]
Wakefield Manufacturing, Phoenix, AZ (SJW-xxxx)                                                                    73mm (1963-64); 33mm (1964-74); 33/70mm (1980-89)

H.V. Waddell Co., Burbank, CA [W, WC, WAD]
1956-1959       68-74 deep groove that varied by a mm or two in either direction
1959-1968   68-70mm deep groove.  (Exact size of groove varies slightly, but is smaller than earlier groove)
1967-1977        During this period, Waddell had at least four different grooves: 68-70mm; 72/92mm; 73mm; 31.7mm Sometimes two on the same LP.
1977-1982        31.7mm (only a handful of examples after 1982)

 

 

I have seen a number of records where the pressing ring and the manufacturer's mark in the dead wax don't correspond. Especially with hit records that sold in the millions, labels contracted with lots of manufacturers to get albums in the stores as quickly as possible. Stampers that were made for one plant had a way of getting sent to other plants, so you will occasionally run across a manufacturer's stamp in the dead wax with a pressing ring that is clearly from somewhere else. In that case, you can assume it was actually pressed somewhere else.  Pressing rings don't lie.

Most manufacturers standardized the size of their pressing dies, so pressings from a given pressing plant normally have the same size ring.  However, there are a few plants that had three or more different sized pressing rings, perhaps because they had record presses built by different manufacturers.  H.V. Waddell, for example, had four different pressing rings in use at the same time.  A given plant's pressing ring might change from time to time as the plant bought new presses or retooled existing machines.  Most big labels standardized their pressing rings so the same stampers could be used at any plant: Beginning in 1962, all Columbia pressings have a 69mm pressing ring, regardless of which Columbia plant pressed them.  RCA switched over to a standard 26mm pressing ring beginning in 1970.  

Fun fact: Since standard LP labels are exactly four inches (or 101mm) across (with some minimal shrinkage from the heat of the presses - once again, thanks to "W.B." for his comment below), you can check pressing ring diameters just by looking at a photo of a label on your computer. There are tens of thousands of them on Discogs. Save the image to your computer and open it with a photo editing program. Increase or decrease the size of the photo so that the label is exactly four inches (or 101mm), and then you can measure the pressing rings by holding a ruler up to the screen.

Original Blue Note deep groove

Finally, it's not really a mystery, but the term "deep groove" has nothing to do with the record groove. It simply refers to the pressing ring on some early LPs which was deeper and more pronounced than on most modern records. Typically, deep grooves are about 1.25-2.0mm wide. Deep groove pressings disappeared in the 1960s as LP manufacturers changed over their presses.  Columbia changed all its presses from deep groove to regular beginning in late 1961.  RCA did the same in late 1969.  

Collectors are mad for "deep groove" pressings, especially Blue Notes (right), and will pay a huge premium for these early releases.  And while a "deep groove" LP can be a good indication that the album is an early or original pressing, that's not always the case.  In fact, Classic Records worked with manufacturer RTI to create a replica deep groove for their Blue Note reissue series in the early 2000s.

Enjoy the music!