Cutting Master Lacquer Disks for the Naxatras debut LP on the AM44 system, directly from analog tape

 

John Delias, the guitar wizard of the popular rock group “Naxatras”, filmed J. I. Agnew while cutting the master lacquer disks, from which the vinyl records of their debut LP were manufactured, at Magnetic Fidelity, and edited the footage to produce this short informative video, offering an insight into this seldom seen, mysterious process.

The recording is reproduced from the 1/4″ master tape on a Telefunken M15A. This particular machine is the more common record/reproduce version, rather than the  preview head, reproduce-only version, encountered only in disk mastering facilities. Preview head tape machines are also available at Magnetic Fidelity, which provide an “advance” signal (sometimes called a lookahead system) to the lathe automation electronics, to automatically vary the spacing between the grooves, based on the dynamics of the music, making life much easier for the disk mastering engineer and greatly simplifying the process.

However, the more complex tape path on preview head tape machines increases the Wow&Flutter, compared to the simpler rec/repro version of the same machine. While it is more difficult and time-consuming to cut masters without using a preview signal, since the groove spacing and depth have to be manually adjusted in real time during the cut, it can offer a substantial improvement in sound quality when cutting directly from tape, if the engineer is able and willing to work this way.

The signal from the tape machine is then directed to the mastering transfer console, which includes signal processing equipment of very high quality, to optimize the signal for the disk medium, ensuring that the record will sound as good as it can get.

In this case, the psychedelic rock of Naxatras travels through a selection of some of the finest vacuum tube equipment ever made, including a Thermionic Culture Custom Green Fat Bustard, a Magnetovolt Sideways, a Manley Massive Passive Mastering Equalizer, and a Manley Variable-Mu Mastering Compressor/Limiter, before reaching the custom cutting amplifier rack, containing the ultra-high-end Magnetovolt Cutting Amplifiers, which were developed by J. I. Agnew.

The cutting amplifiers are driving a Caruso stereophonic feedback cutterhead, a state-of-the-art, Swiss-made transducer, developed by Flo Kaufmann.

This lathe is the AM44, based on an original Neumann lathe body, made of grey cast iron in the 1940’s. The AM44 project is an ongoing effort to make available a limited number of high quality disk mastering systems based on NOS Neumann bodies, along with newly manufactured parts. The project was initiated several years ago by Flo Kaufmann, who was successful in locating these long-lost Neumann bodies. This example is the first ever functional prototype of the AM44, put together by the Magnetovolt team under the direction of J. I. Agnew, who designed several of the parts and circuits and has been contributing to the AM44 project since 2016.

If you would be interested in purchasing an AM44 or other disk recording lathe, you are welcome to contact us to discuss your needs. We can supply lathes, complete systems or just parts, and we can also restore, repair and modify any relevant equipment of any manufacturer and vintage.

If you are simply looking for information about such systems, we are regularly updating our recently-introduced Analog Disk Recording Information Portal.

J. I. Agnew is offering Analog Sound Recording and Mastering services, so do not hesitate to ask if you are interested.

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