Mercury Matrix Number Variations

A “Matrix Number”, stamped (or inscribed) information placed between the last groove and the label, is always there, to indicate record number, mother stamper, and pressing plant.

With matrix number type, we can surmise the era when each platter is pressed. And Label variations also used for each vinyl also helps a lot to guess the pressed era.

Please note, that the variations on this site does not cover all known to exist: there are so many exceptions. So please understand the variations on this site are basic frameworks to identify famous patterns.

Matrix Number Variations: 1959? -

MG 20573A MS1  FF Matrix imprints of Mercury MG-20573 Side-A This stamper may indicate this platter was pressed using the first-cut lacquer (MS1). However, there are no mother/stamper indications. Double-F inscription (one F super-imposed on another F) probably stands for the initial of mastering engineer (who is currently unknown).

In 1960, all Mercury pressings moved to Mercury Richmond plant, Indiana (later became Philips Recording Corp. then PRC Recording Corp.). The plant was originally owned by US Decca, and Mercury acquired the plant in May 1958. Except Living Presence series, all platters have yet another imprinted matrixes, whose letter is vertically longer.

Matrix suffix is started with MS (early 1960s) - later changed to M (with a few exceptions).

This type can be found on such series as

• MG-20000 Series Monaural (Popular, 12-inch LP, middle MG-20400 and beyond)
• SR-60000 Series Stereo (Popular, 12-inch LP, about SR-60100 and beyond)

and most of Mercury's subsidiaries (second EmArcy, Philips US, Smash, Fontana US, Limelight) also have this matrix stamps. This type can be found even in the 1970s. Furthermore, later pressings of Living Presence series (after George Piros ceased relationship with Mercury) also have this type of matrix stamps.

This type doesn't have explicit mother/stamper numbers, but on some platters handwritten lines are added on the dead wax - this might represent stamper generations.

This type also has inscribed FF, RI, RR, MR or some others. This inscription is said to denote the initial of mastering enginners.

SR 60097A MS1  A1  I Matrix imprints of Mercury SR-60097 Side-A This stamper may indicate this platter was pressed using the first stamper (1) from the first mother (A) from the first-cut lacquer (MS1). This is an unusual case - Richmond type matrix with RCA Victor Indianapolis indicator. Probably there were some unknown reason to press at Indy plant using the lacquer cut at Richmond plant.

MG 20939A M1  I  RR Matrix imprints of Mercury MG-20939 Side-A This stamper may indicate this platter was pressed using the first-cut lacquer (M1). However, there are no mother/stamper indications. Double-R inscription (RR) probably stands for the initial of mastering engineer (who is currently unknown). And handwritten I probably indicate the first stamper.