How to Read Matrix Runout Codes: Find the Plant, the Stamper and the First Pressing Before You Buy a Record

Side four was clean. Sides one and two of the same album, pressed in the same factory, were not. I heard it on a system built to expose defects without mercy. Same plant. Different stampers. Different result.

That finding is why I now read the dead wax before I read the price tag. If you want to know how to tell if a record is a first pressing, which plant made it and which stamper it came from, the answer is not on the hype sticker. It is etched and stamped into the shiny band between the last groove and the label. Here is what each mark means, which plants I look for, which make me slow down, and the routine I follow before I pay.

Same plant, different records: the test that sent me to the dead wax

In April 2026 I published New Vinyl Is a Scam? The Dirty Truth About Modern Pressings. I do everything right with my records, and too many brand-new, factory-sealed premium pressings still sounded terrible. Not all of them. Enough of them that I had to investigate.

So I tested four albums from one of the most universally recognised catalogues in audiophile history: different pressing runs, some from respected plants, one from a plant with known quality issues. The chain was my McIntosh MT5 turntable into the phono stage of the C12000, then MC611 monoblocks and Wilson Yvettes. Every record went through a Degritter Mk II first, with lab-grade distilled water, solution and filters changed every 20 to 30 cycles, and a carbon-fibre brush before every play. Zero fingerprints.

One album had low-level clicks, audible only in dead-silent passages. Acceptable, not perfect. Two had significant surface noise that improved as the needle moved inwards: textbook non-fill. The worst was a premium anniversary edition at $80, with pervasive noise on the first side, cyclical stamper defects and a noise floor that dominated the quiet passages. The short version is in four albums, and the dearest was the worst.

Then came the finding that changed my perspective entirely. Three of the four came from the same plant, one generally considered upper tier. So the plant alone was not the variable. Each side of each record uses a different stamper, and the stamper decided what I heard.

You are not unlucky. The entire run is compromised.

Buying a second copy pressed from the same stamper fixes nothing. Your best clue to which run you are holding is in the dead wax.

What the dead wax is: lacquer, father, mother, stamper

Wikipedia's entry on matrix numbers calls the dead wax the run-out groove area or matrix area, and its codes are stamped, handwritten, or both. Every stage of manufacture can leave a mark there.

It starts with a lacquer, the master disc a cutting engineer cuts on a lathe. Then comes plating, set out step by step in the Discogs profile of RTI, Record Technology Incorporated. In the 3-step process the lacquer makes negative fathers, the fathers make positive mothers, and the mothers make the stampers. In the 2-step process, used for small runs, the father becomes the stamper. In the 1-step process, often found on Mobile Fidelity records, the lacquer makes a single negative convert that presses the vinyl directly; the profile says removing those two steps improves sound quality. More than 30 of my own records are one-step pressings.

The stamper is the metal face a heated vinyl biscuit is squeezed against, one per side, and as I said in the film, it wears over time and picks up scratches. A damaged one leaves the same pop or crackle, once every revolution, on every copy. Buy ten; all ten have it.

So read the marks by where they came from:

• The cut. The matrix number identifies the release and side, a suffix counts the lacquer cuts, and the engineer often adds initials or a signature, such as "KPG@CA".
• The plating. Plating numbers and marks, some of them backwards: RTI's "(3)" records the 3-step process, and Optimal Media's profile says its plating marks are inscribed into the mother plates "and therefore appear mirrored", so "VI" is really "1|".
• The plant. A name stamp such as "QRP" or a job number, and sometimes a stamper ID: MRP's hand-etched "A4" or "#12", or RTI's pre-1983 tally.

Three stages, three sets of fingerprints, all in one shiny band.

Reading the codes: matrix, side, signature, plant

Take a real runout. On Analogue Productions' 2021 repress of the Sonny Rollins Quartet's Tenor Madness, Discogs transcribes side A as "PRLP-7047-A2 KPG@CA QRP KEVIN GRAY". Four kinds of information sit in that one line.

Slide across for readable labelsStartEnd

Read every label as live text

• PRLP-7047-A2
• KPG@CA
• QRP
• KEVIN GRAY
• PRLP-7047: Matrix number, follows Prestige catalogue LP 7047.
• A2: Side A plus suffix.
• KPG@CA: Cutting engineer, Kevin Gray at Cohearent Audio, etched.
• QRP: Plant, Quality Record Pressings, stamped.
• KEVIN GRAY: Engineer's name, stamped.
• thin script = etched; block letters = stamped

• The matrix number. "PRLP-7047" follows the Prestige catalogue number, LP 7047.
• The side and suffix. "A2" gives side A plus a suffix; Wikipedia puts the cut number in that position.
• The cutting engineer. "KPG@CA" is Kevin Gray at Cohearent Audio, etched; "KEVIN GRAY" is stamped.
• The plant. "QRP" is the stamp of Quality Record Pressings. The release notes say only "QRP" and "KEVIN GRAY" are stamped; the rest is etched.

Other signatures you will meet: "RL" is Bob Ludwig, and on the first US pressing of Led Zeppelin II it sits beside a small "ss" for Sterling Sound. "CB" on a 2019 repress of Van Halen's 1984 is Chris Bellman of Bernie Grundman Mastering. Some are playful; Wikipedia notes that George Peckham often signed his cuts "Porky". Treat initials as evidence, not proof: Bellman's Discogs page warns against confusing him with four other engineers who also sign "CB". Reading all of this was step one in the film, and later a Daily: learn to read the dead wax.

How to tell if a record is a first pressing

You prove a first pressing by matching the whole runout to the earliest documented variant, never by one digit.

The cut number is the fair place to start. Wikipedia's example "12345-3" is the third cut of that side, so a "-1" usually marks the first. But the same entry is blunt: a first cut could be a rejected cut, and "a matrix number in itself is not proof of an original pressing".

Led Zeppelin II shows why the details matter. Discogs lists the US first pressing as Bob Ludwig's "hot" cut, pressed by Monarch: side A reads "ST-A-691671-MO", with "RL", that small "ss" and a circled "MR" stamp identifying the plant. Those copies were withdrawn early because the high bass levels made low-grade cartridges mistrack, and buyers returned the album believing it was defective. A much less hot recut became the far more common copy. That single Monarch release lists 13 runout variants for side A. Thirteen. Compare the whole string, every letter and symbol, not only the number that flatters your copy.

On a new release, "first" matters less than "which plant, which stamper". For classic catalogues not licensed to audiophile labels, my film's advice runs the other way: a near-mint '70s original, pressed when quality control was tighter, can significantly outperform a modern reissue, and Japanese pressings of the late '70s and early '80s have historically outstanding quality control.

The plants I look for: QRP, RTI, Pallas, Optimal Media

In the film I named four plants that produce exceptional vinyl: Quality Record Pressings, RTI, Pallas in Germany and Optimal Media. There is a massive difference between a record pressed at QRP or RTI and one from a high-volume facility. The catch: QRP stamps its name, but most plants, including the two I flag for caution, leave only numbers. My cheat sheet:

Source: Discogs label profiles and the release pages named.

Two warnings. First, a plating number is not a pressing credit. RTI's profile says a record plated there "doesn't necessarily mean the plant also pressed it". The 2022 Analogue Productions sampler The Wonderful Sounds of Quality Record Pressings reuses older metal parts, so its runouts carry RTI numbers, yet QRP pressed it. Second, reputation is not a guarantee: three of my four test copies came from an upper-tier plant, and none of the four was perfect. A great plant name improves the odds. The stamper settles the bet.

Proceed with caution: what GZ and MRP marks mean

GZ Media, in the Czech Republic, is the world's largest record manufacturer, and its Loděnice plant has made vinyl continuously since 1951. As I said in the film, GZ also holds majority stakes in Memphis Record Pressing in the United States, Precision Record Pressing in Canada and SNA in France; MRP's Discogs profile dates its acquisition to 31 December 2015. A record that says pressed in the USA or the EU has a significant chance of having gone through a GZ-affiliated plant.

In GZ's engraving an "E" means a 12-inch stereo LP at 33⅓, and the six-digit number roughly dates the job: 2025 jobs run from 28XXXX to 30XXXX. Hand-etched stamper IDs like A4 or #12 beside an "MRP" number mean Memphis pressed the record itself. Ignore the wrapper: GZ's profile says "Made in USA" or "Made in CZ" on stickers or shrink-wrap should not be used to identify a plant.

If you see GZ codes, MRP stamps, proceed with caution. It does not mean it will be bad, but know that quality will vary widely.

In the film I called the complaints about GZ quality consistent, documented and loud for over a decade: forum after forum, collector after collector, the same patterns of non-fill, warping and surface noise on sealed records. But caution is not a verdict. It means research that specific pressing and stamper, buy where you can return, and listen before you trust. Homework, not a boycott.

Using Discogs before you buy

Discogs is the nearest thing we have to a public register of runouts, and the quickest way to tell what pressing a record is. Each release page lists the dead-wax text as Matrix / Runout, under Barcode and Other Identifiers. How I use it:

1. Find the release that matches your sleeve and labels, then compare its Matrix / Runout lines with your copy character by character, symbols included.
2. Read the notes. They say what is stamped and what is etched.
3. Read the credits slowly. Pressed By, Plated At and Lacquer Cut At are separate credits, and GZ gets only a Plated At credit unless the pressing can be clearly determined.
4. Watch for misreads. A hand-etched Optimal "B" can pass for a 3, an 8 or a D, and on GZ numbers a 2 can look like a Z.
5. Take the code to the Steve Hoffman forums and find out what owners heard from that pressing.

Discogs tells you what a record is. Owners tell you what it sounds like. You need both.

A buying routine before money changes hands

1. Research the pressing: plant, cutting engineer, any reports on specific stampers.
2. Check the runout. In a shop, tilt the record under the light; online, ask for clear photos of the dead wax on every side.
3. Play the outer grooves first. Non-fill is almost always worst there, because the vinyl biscuit is pressed from the centre outwards and the outer edge fills last. My Daily rule: listen to the outer grooves first.
4. Clean, then judge. An ultrasonic cleaner lets you hear exactly what the pressing gave you, but cleaning reveals the pressing; it cannot fix it.
5. Return defective pressings, and note the side and stamper code first. A replacement from the same stamper brings the same defect home.

When the pressing is right, vinyl does something streaming cannot touch. But at $30, $50 or $80 a record you should get better than a used copy from the '70s, and nobody would accept a new car with scratches from the factory. I am not telling you to stop buying vinyl. I am telling you to stop buying blindly.

Sides one and two taught me that, and side four proved it: same album, same plant, different stampers. The clue was never on the sticker. It was in the dead wax. Read it first. Period.

Frequently asked questions

How do you tell if a vinyl is a first pressing?

You tell if a vinyl is a first pressing by matching its whole runout to the earliest variant documented on Discogs. A "-1" cut number is evidence, not proof, because a first cut can be rejected.

What is a vinyl matrix number?

A vinyl matrix number is the code stamped or handwritten in the dead wax that identifies the release and side, often with a cut number as a suffix.

What does matrix runout mean?

Matrix / Runout is the Discogs label for everything written in the dead wax: matrix number, side, cut, engineer signature, plating and plant marks.