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: 1951? - 1954?

YMG 25171A  2  M  B Matrix imprints of Mercury MG-25171 Side-A This stamper may indicate this platter was pressed using the second mother or stamper (B) from the second-cut lacquer (2).

This is a successor of the very early variation - matrix number's prefix was changed to YMG. The imprinted letter is a bit smaller than the earliest variation.

This type can be found on such series as

• 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)

and earlier pressings of some

• MG-26000 Series (Jazz, 10-inch LP)
• MG-36000 Series (Jazz, 12-inch LP)

also have this type.

However, please note that most of Norman Granz-produced Jazz releases still have MG prefixes (with a few exception).

It seems that machine-stamped “M” was gradually switched to handwritten inscribed M. And it is also noticeable that some Classical releases already use MF matrix suffix.

Some of the platter with this type - pressed before 1953 - are cut with non-RIAA equalization curve. As far as I know, Mercury switched equalization curve from Mercury one to the RIAA curve, althouth there may be some exceptions.

YMG15046A  MF2 Matrix imprints of Mercury MG-15046 Side-A. This stamper may indicate this platter was pressed using a certain stamper from the second-cut lacquer (MF2).

YMG26043A  M  B Matrix imprints of EmArcy MG-26043 Side-A M is not imprinted one but inscribed one. This stamper may indicate this platter was pressed using the second mother or stamper (B) from the first-cut lacquer (none).