Copper


Revolutions per minute


The DMM Dubplate, Vol. 1 and the Art of Pushing...

Issue 149REVOLUTIONS PER MINUTE

Part One and Part Two of this series were published in Issue 147 and Issue 148. Was DMM (direct metal mastering) ever intended to offer a sonic improvement, compared to “prior art”? When...

The DMM Dubplate, Vol. 1 and the Art of Pushing...

Issue 148REVOLUTIONS PER MINUTE

In the previous episode (Issue 147) we dived into my past encounter with the name of Günter Pauler, and we now come back to the present event. Which is a shiny new...

The DMM Dubplate and the Art of Pushing the Bou...

Issue 147REVOLUTIONS PER MINUTE

Before I begin writing about the DMM Dubplate Vol. 1 disk, recently released by Stockfisch Records of Germany, some background is essential for a full appreciation of what this actually means, in technical and...

Martin Theophilus of The Museum of Magnetic Sou...

Issue 146REVOLUTIONS PER MINUTE

Martin Theophilus is the Executive Director of the Museum of Magnetic Sound Recording (MOMSR), a private collection of recording machines, tapes and other materials, along with a companion website. The site contains...

Martin Theophilus of The Museum of Magnetic Sou...

Issue 145REVOLUTIONS PER MINUTE

Martin Theophilus is the Executive Director of the Museum of Magnetic Sound Recording (MOMSR), a private collection of recording machines, tapes and other materials, along with a companion website. The site contains a...

Martin Theophilus of The Museum of Magnetic Sou...

Issue 144Revolutions per minute

Martin Theophilus is the Executive Director of the Museum of Magnetic Sound Recording (MOMSR), a private collection of recording machines, tapes and other materials, along with a companion website. The...

The Giants of Tape, Part 10: The Telefunken M15...

Issue 143REVOLUTIONS PER MINUTE

Part One, Part Two and Part Three of J.I. Agnew’s look at the Telefunken M15A tape machine ran in Issues 140, 141 and 142. His series on the M15A concludes here. One of the...

The Giants of Tape, Part Nine: The Telefunken M...

Issue 142REVOLUTIONS PER MINUTE

Part One and Part Two of J.I. Agnew’s look at the Telefunken M15A tape machine ran in Issue 140 and Issue 141. The series continues here. The Telefunken M15A could...

The Giants of Tape, Part Seven: The Telefunken ...

Issue 140REVOLUTIONS PER MINUTE

To follow a few installments dedicated to Ampex (Issues 136 and 137) and MCI (Issues 138 and 139), it is time to return once again to the Old World, and discover Europe’s best-kept audio secret! While...

The Giants of Tape, Part Six: the MCI JH-110, P...

Issue 139REVOLUTIONS PER MINUTE

In the previous episode, we talked about the merits of the MCI JH-110 professional studio tape recorder. Now it’s time to have a look at its not-so-strong points. Despite its...

The Giants of Tape: The MCI JH-110, Part One

Issue 138REVOLUTIONS PER MINUTE

In the last few installments in this series, California was in the spotlight, with discussions of Ampex and their ATR-100 series of tape machines (see Issue 135, Issue 136 and Issue 137). This time,...

The Giants of Tape, Part Four

Issue 137REVOLUTIONS PER MINUTE

This time we’re going to have a look at another Ampex tape machine, an ATR-104 with plenty of extras! It lives at Airshow Mastering in Boulder, Colorado (not too far from PS...

The Giants of Tape, Part Three

Issue 136REVOLUTIONS PER MINUTE

In Part One (Issue 134), J.I. Agnew profiled the legendary Studer A80 open reel deck. Part Two (Issue 135) covered the equally-storied Ampex ATR-100 Series tape machines. In Part Three,...

The Giants of Tape, Part Eight: The Telefunken ...

Issue 141REVOLUTIONS PER MINUTE

In the previous episode (Issue 140), the Telefunken M15 and M15A machines were introduced. Time to look at them under the microscope. The M15A transport was available in 1/4-inch, 1/2-inch, 1-inch and...

The Giants of Tape, Part One

Issue 134REVOLUTIONS PER MINUTE

Tape machines have been made in various shapes, sizes, forms and formats, for all kinds of applications. Magnetic tape recording in its present form came many decades after the original...

The Big Move, Part Three

Issue 133REVOLUTIONS PER MINUTE

In Part One and Part Two, J.I. Agnew wrote about the difficulties of moving an entire recording and mastering facility, complete with machine shop, grand piano, literal tons of equipment...

The Big Move, Part Two

Issue 132REVOLUTIONS PER MINUTE

In Part One (Issue 131), J.I. Agnew wrote about the difficulties of moving an entire recording and mastering facility, complete with machine shop, grand piano, literal tons of equipment and...

The DMM Dubplate, Vol. 1 and the Art of Pushing...

Issue 150Revolutions Per Minute

Parts One, Two and Three of this series appeared in Issue 147, Issue 148 and Issue 149. In listening to the direct-metal-mastered Stockfisch Records DMM Dubplate, Vol. 1, I almost couldn’t believe that the source was...

The Big Move, Part One

Issue 131REVOLUTIONS PER MINUTE

Ten years ago, I moved to a new building carrying a couple of truckloads of equipment, with which I was planning on building up a mastering studio, an electronics workshop...

The Story of a Vintage Piano, Part the Second

Issue 130REVOLUTIONS PER MINUTE

In Part One, J.I. Agnew began his search for the perfect piano for recording. He noted that finding a piano that would sound as much like real life in recordings was...

The Story of a Vintage Piano, Part the First

Issue 129REVOLUTIONS PER MINUTE

In previous issues I have gone into some detail about disk recording, tape recording, the technical challenges of accurate reproduction, audio electronics, vacuum tubes and even professional recording facilities. But,...

Vintage Tube Amplification During a Lockdown, P...

Issue 128REVOLUTIONS PER MINUTE

In Part One, (Issue 127), J.I. told us about being suddenly locked down and without an amplifier for his music system, necessitating his purchase of a vintage H.H. Scott 299...

Vintage Tube Amplification During a Lockdown, P...

Issue 127REVOLUTIONS PER MINUTE

There are some things that you just have to do at some point in your life. After reading Zen and the Art of Motorcycle Maintenance by Robert M. Pirsig and Jack Kerouac’s On...

Vertical Tracking Angle Meets Stylus Rake Angle...

Issue 126REVOLUTIONS PER MINUTE

In Issue 125, J.I. covered the mechanical aspects of record cutting with respect to stylus rake angle (SRA) and vertical tracking angle (VTA). The series concludes with a further examination...

Vertical Tracking Angle Meets Stylus Rake Angle...

Issue 125REVOLUTIONS PER MINUTE

The geometric considerations with regard to vinyl disk recording and reproduction are plenty and can get quite complex. In fact, the entire first section of the Disk Recording Anthology Volume 1:...

The Coil and Its Significance for Recorded Sound

Issue 124REVOLUTIONS PER MINUTE

A few days ago I was in the lab (which in itself is hardly surprising, considering that a significant part of my life is spent there) winding some tiny coils...

Eight Decades of Wrong Assumptions: The Loudnes...

Issue 123REVOLUTIONS PER MINUTE

Let’s cut straight to the chase: Who won the loudness wars? Nobody. (For the benefit of those unfamiliar with the term, the “Loudness War” refers to the practice of trying...

How Loud Is a Record?

Issue 122REVOLUTIONS PER MINUTE

n this article, I shall attempt to shed light on an often misunderstood concept: loudness. Let us begin from the very basics. Three folks are playing a tenor sax, a...

How Hi Would You Like Your Fi?

Issue 121REVOLUTIONS PER MINUTE

“High Fidelity” is an ambiguous term. How much Fidelity is required to be considered High Fidelity? “Fidelity” in a listening system refers to its ability to reproduce sound that is...

Acoustic Design Consultant Philip Newell, Part Two

Issue 120REVOLUTIONS PER MINUTE

In Part One (Issue 119), acoustical design consultant Philip Newell talked about his early years in the 1960s and 1970s, his experiences with Virgin Records and entrepreneur Richard Branson, the...

Sound Pilot: Interview with Acoustic Design Con...

Issue 119REVOLUTIONS PER MINUTE

Philip Newell has been professionally involved in audio since 1966. He has done it all, from an apprenticeship in audio electronics while studying radio and television servicing, to doing live...

The Long-Lost Record Label Concept, Part 2: Sel...

Issue 118REVOLUTIONS PER MINUTE

In Issue 117 J.I. talked about the origin of the term “record label,” and the evolution of record companies over the decades. Here, he has some additional and provocative perspective. – Ed....

The Long-Lost Record Label Concept – Part 1

Issue 117REVOLUTIONS PER MINUTE

The record label, that round paper label in the middle of each record, has existed in one form or another since records first became flat (some believe the Earth will...

Colored Vinyl: Eye Candy, But is It Ear Candy?

Issue 116REVOLUTIONS PER MINUTE

Records, from the age of shellac to the vinyl era, have traditionally been black. Artwork was typically confined to the small round paper label on the record itself and to...

How Not To Fix Things (Especially Things That T...

Issue 114REVOLUTIONS PER MINUTE

There are few things more frustrating than having trusted an expert to fix something, only to have it returned more broken than it was to begin with! The wrong choice...

Are 180-Gram Vinyl Records Really Better?

Issue 115REVOLUTIONS PER MINUTE

Disk records have been around for a while, long before they reached their vinyl form. Since then, vinyl records have been available in different sizes and profiles. During the mass-manufacturing...

Vinyl and Absolute Polarity: Q&A, Part Two

Issue 113REVOLUTIONS PER MINUTE

In Part One of this dialog between J.I. Agnew and reader/engineer Bob Lehman (Issue 112), they delved into the technical aspects of vinyl record manufacturing and absolute polarity. The dialog continues here....

Vinyl and Absolute Polarity: Q&A

Issue 112REVOLUTIONS PER MINUTE

Bob Lehman, a classically-educated retired electrical engineer and long-term audiophile, asked some very good questions upon reading my column in Issue 110, “Vinyl and Absolute Polarity: A Technical Exposition.” What follows...

For the Record: Restoring a Vintage Disc Cuttin...

Issue 111REVOLUTIONS PER MINUTE

A customer recently imported a vintage Presto 75A disk recording lathe from the US, with a view to cutting records in Europe. [J.I. is based in Europe – Ed.] He quickly...

The Giants of Tape, Part Two

Issue 135REVOLUTIONS PER MINUTE

The former Ampex building in Hayward, California. Courtesy of Wikimedia Commons/Pretzelpaws.   Ampex doesn’t really need much of an introduction. It was the company that commercialized magnetic tape recorders in their...

Vinyl and Absolute Polarity: A Technical Exposi...

Issue 110REVOLUTIONS PER MINUTE

One might think that the whole issue of absolute polarity for vinyl records, a medium essentially invented around 130 years ago, would have been adequately discussed and standardized by now,...

How to Lie with Measurements

Issue 109REVOLUTIONS PER MINUTE

In view of my recent series on linearity and other technical topics before that, the time is perhaps now ripe to discuss audio measurements. I will focus on what is...

Linearity in Audio, Part Three

Issue 108REVOLUTIONS PER MINUTE

Up to now we have only talked about the most basic tube amplifier design, consisting of one triode tube in a Class A1 single-ended configuration. There are numerous configurations and...

Vacuum Tubes: A Brief History

Issue 103REVOLUTIONS PER MINUTE

Vacuum tubes, also known as thermionic valves, or just valves in the UK, are electronic devices whose operation is based on thermionic emission. This is defined as the emission of electrons from the surface...

An Ode to Cassette Tape: Part Two

Issue 102REVOLUTIONS PER MINUTE

When thinking of the ultimate cassette deck, many people think of Nakamichi. The company made some of the most impressive cassette decks ever. They were used by audiophiles and professionals,...

An Ode to Cassette Tape - Part One

Issue 101REVOLUTIONS PER MINUTE

I still remember how, as a very young boy, I had to handle a 7-inch record with both hands and I still could barely manage to put it on the...

Variations on a Theme of 1/4-Inch Tape

Issue 100REVOLUTIONS PER MINUTE

In our previous episode, we had a look at the history of magnetic recording. This time, I shall focus specifically on 1/4-inch tape and the mind-boggling number of applications it...

The Multiple Facets of Magnetic Recording: A Br...

Issue 98REVOLUTIONS PER MINUTE

Grooved media – phonograph cylinders, gramophone records and so on – kickstarted the recording industry and were the dominant commercial recording and playback formats up until the Second World War....

How Do We Get It Out Of There?

Issue 97REVOLUTIONS PER MINUTE

As we have examined throughout several previous issues of Copper, it takes an insane amount of precision engineering to store sonic information in record grooves and see it through multiple stages...

From The Cylinder To The Disk Record...And Back?

Issue 96REVOLUTIONS PER MINUTE

When the first demonstrations of sound recording and subsequent reproduction were conducted, using Edison’s original 1877 phonograph, the emphasis was placed on promoting the machine, not the recordings. In fact,...