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 Vatiations: 1949 - 1951?

MG 20009A  1 Matrix imprints of Mercury MG-20009 Side-A (early pressing) This stamper may indicate this platter was pressed using the first-cut lacquer (1).

This is the very first type, used from 1949 (when Mercury started to release microgroove LPs) to 1951 or around. The imprinted letter is bigger than later ones.

Very early pressings of

• MG-10000 Series (Classical, 12-inch LP)
• MG-15000 Series (Classical, 10-inch LP)
• MG-20000 Series (Popular, 12-inch LP)
• MG-25000 Series (Popular, 10-inch LP)
• MG-30000 Series (Children, 10-inch LP)
• MG-35000 Series, MG C-100 Series, MG C-500 Series (Jazz, 10-inch LP)
• MG C-600 Series (Jazz, 12-inch LP)

have this type of matrix stamps.

Very early platters are very heavy and non-flexible (such as acetate discs). It might be the same kinds of 78rpms of the last years (made of vinyl, not of shellac) but I'm not certain.

Matrix numbers may or may no have “1” suffix. Or it may be other numbers such as 2, 3, 4,... (I've seen a copy with 5). Some platters have extra X, such as “2X”.

Some platters even have additional “M” imprints, as well as A, B, C,... imprints (they are common on a bit later pressings).

Most (maybe all) of the platters with this type are cut with non-RIAA equalization curve.

MG 25012A  2X  M  C Matrix imprints of Mercury MG-25012 Side-A (late pressing) This stamper may indicate this platter was pressed using the third mother or stamper (C) from the second-cut lacquer (2X).