Revolutions Per Minute

    Around the World In 80 Lathes, Part 23

    Issue 173

    Having visited Japan and their disk recording lathes in previous issues (see Issue 171 and Issue 170), it is now time to travel back to Europe, this time to a country with a long history in the field of sound recording dating back to the late 1800s, with the pioneering work of Valdemar Poulsen and the early beginnings of what was to become the Technical University of Denmark. To name just a few, the country has been the home of the Electrical Fono-Film Company (established in the 1910s), Fonofilm Industri A/S (in the 1930s), TONO (a record label established in 1936, engaged in conducting sound recordings in Denmark), Ortofon (manufacturing disk recording cutter heads, playback cartridges and related products since 1918), Bruel & Kjaer (one of the world’s leading manufacturers of acoustics and vibration measurement instruments, founded in 1942), driver and speaker manufacturers Scan-Speak A/S (1970) and Dynaudio (1977), the well-known Bang & Olufsen (1925) and the topic of this episode, Lyrec Manufacturing A/S, founded in 1945 in Skovlunde, Denmark.

    Lyrec developed a range of disk recording lathes, tape recorders, and preview head tape reproducers for use with pitch and groove depth automation systems for disk mastering lathes, turntables, industrial high-speed tape duplication systems. Along with analog and later digital loop bin systems. They also offered magnetic tape-based instrumentation recorders for industrial, medical and aerospace applications, as well as cassette tape loaders, automatic wrapping machines for shrink-wrapping of cassette tapes, VHS tapes, CD/DVD jewel cases and possibly other media. They also manufactured what was probably their biggest and most long-lasting contribution to the disk recording industry: a range of synchronous AC motors, designed to drive disk recording lathe platters in a direct-drive configuration. These motors were extensively used by Neumann on their lathes, up until the introduction of the VMS-80, when they moved to a different type of motor and the Lyrec synchronous motors were discontinued.

    Not much information has survived regarding the people behind Lyrec. Neither the founders, nor the engineers, are known by name. The final product the company manufactured was introduced in 2004, a digital loop bin system for high-speed cassette tape duplication. The company folded shortly thereafter. The last three decades of Lyrec saw it focus on tape duplication systems, wrapping machines and on-body printing systems for cassette tape shells.

    In 1945, when the company began operation, Lyrec introduced an early synchronous AC motor for disk recording lathes and turntables, along with a 15-watt cutting amplifier and a monophonic cutter head. Two years later, they introduced the Lyrec SV-2, a disk recording lathe intended for portable use (provided you could find some really strong people to haul it around), for direct-to-disk recording.

    The SM-3, a further development of their synchronous AC motor, arrived in 1948, followed by an improved version of the SV-2 lathe a year later and the company’s first tape machine in 1950.

    From the SV-2, the model designation jumped straight to the SV-7 in 1954, along with the SM-7, the third generation of their synchronous AC motors. The SV-7 was to be followed by the SV-8 just a year later, this being the very first stereophonic disk recording offering of the company.

    The Lyrec SM-8, the legendary synchronous AC motor that found application as the main motor for the Neumann VMS-70 and VMS-66 disk mastering lathes, was introduced in 1955, representing the fourth generation of this theme, and the final development in this direction. It was responsible for cutting masters for probably more records in the stereophonic era than any other motor and perhaps even all other motors combined. It remained in production in large numbers unchanged up until 1976 (21 years), with many of them being purchased by Neumann.

    Being a synchronous AC motor, the Lyrec SM-8 (and all their previous products) could only spin at what is known as synchronous speed, locked to the frequency of the AC power driving the motor. There were no control electronics; the motor could be powered directly from the electricity grid. However, since there could only be one synchronous speed for a given power supply frequency and the motor had to provide speeds of 33-1/3, 45 and 78 rpm, it was not actually one motor, but rather three separate synchronous AC motors stacked one on top of the other, all sharing the same shaft. Each disk speed had a dedicated motor section on the SM-8.

     

    A Lyrec Disk Mastering lathe. Photo courtesy of Eward Nowill.

    A Lyrec Disk Mastering lathe. Photo courtesy of Eward Nowill.

    However, pulling the rotational inertia of a massively heavy platter into synchronicity was not possible, due to the design limitations of such a motor, so the synchronous motors were not self-starting. To get them to start, a separate induction motor was placed above the three synchronous motors, for a total of four motors sharing the same shaft. The induction motor would bring the platter up to speed, from where the synchronous motor of the appropriate (large) number of poles would take over and keep it spinning at the right speed.

    The complications did not end there. About half the world used 50 Hz as their powerline frequency and the other half used 60 Hz, at different voltages. To operate correctly in different parts of the world, Lyrec made dedicated 50 Hz and 60 Hz versions. Most of these were single-phase supply motors, using capacitors to accomplish the phase shift required to keep the motor spinning. However, Lyrec also made three-phase versions that did not require capacitors. There were 50 Hz and 60 Hz versions of these as well!

    As if this wasn’t confusing enough, Lyrec also made variants of the SM-8, offering 66-2/3 rpm instead of 78 rpm, in 50 Hz and 60 Hz versions, in both single-phase and three-phase…

    And as if this was not complicated enough, synchronous speed is defined according to the formula Ns = 120 f/p (where Ns is synchronous speed in rpm, f is the powerline frequency and p is the number of poles of the motor), and there can only be an integer number of poles. A motor can only have entire poles; there cannot be fractions of poles, such as half poles. A motor can have 4 poles, or 5 poles, for example, but it cannot have 4-1/2 poles! As such, the SM-8 required 216 poles to spin at 33-1/3 rpm at 60 Hz, and 180 poles for the same speed at 50 Hz. But the other speeds were nowhere near as straightforward! At 60 Hz, 160 poles would give a speed of 45 rpm. However, at 50 Hz, there is no integer number of poles that would result in 45 rpm. The nearest integer is 154 poles, resulting in 45.112782 rpm! Similarly, at 60 Hz, the nearest integer number of poles for a nominal 78 rpm speed was 92 poles, resulting in 78.26 rpm. At 50 Hz, 77 poles would result in 77.922 rpm, which was deemed close enough. It becomes clear that neither the Lyrec lathes, nor the Neumann lathes using Lyrec motors, could agree on speed between the US and Europe, while none of them could produce an exact 78 rpm! In other words, a 45-rpm master cut in the US and the same master cut-in Europe would result in disks that did not play at the same speed!

    In 1958 Lyrec introduced a preview head tape machine, to accompany the pitch automation systems they were building into their lathes. The model TR-18 was to be followed by the TR-33 in 1960. Lyrec used a 0.5-revolution delay system for their lathe automation systems and preview head tape machines, which was incompatible with Neumann’s 0.6 revolution delay and Scully’s 1.0 revolution delay (see Issue 153 for a detailed explanation of preview head tape machines, delay times and pitch/depth automation systems for disk mastering lathes). When introducing the VMS-80, Neumann also shifted to the 0.5 revolution delay, presenting, for the first time in history, a united European front in lathe automation system delay times. By that point, that were merely two manufacturers left, Lyrec and Neumann, with Lyrec having long-discontinued their disk recording lathes and preview head tape machines.

    The SV-10, the final development in Lyrec disk recording lathes, was introduced in 1962, in collaboration with Ortofon. In total, between 30 and 50 Lyrec lathes are estimated to have been made between 1947 and 1965. This comes down to around two machines per year, each with unique features, indicating a largely “handcrafted” approach.

    From the mid 1960a until the company folded in the mid 2000s, their focus shifted away from the disk medium, with an emphasis on tape recorders and industrial manufacturing equipment. Lyrec pursued the medical, aerospace and industrial instrumentation markets, while continuing to serve the media manufacturing sector for audio and video formats. The handcrafted spirit was gone for good by the end of the 1960s.

    In the next episode, we will be looking at some of the features of Lyrec disk recording lathes.

     

    Header image: a Lyrec SM-8 motor disassembled. Courtesy of Eward Nowill.

    One comment on “Around the World In 80 Lathes, Part 23”

    1. While the motor had a start-up feature, I was taught to just spin the disk with my hand and wait for the strobe markings on the side of the Neumann turntable to stabilize.

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