Maxicut was the name given in 1978 by Studios 301—the recently renamed and re-equipped EMI Studios, Sydney—to a series of modifications made to their Neumann VMS-70 disc-cutting lathes. The modifications were contained on two printed circuit boards that replaced the standard Neumann SV-66-V2 and TE-66 cards.
Maxicut was a process that allowed engineers to cut lacquers at a significantly higher volume level, typically 6-8dB, without the normal tracking problems that less expensive turntable/cartridge units would exhibit in trying to track the higher levels (groove jumping). Maxicut accomplished this with no loss of the program signal and without significant loss in program time.
Former Studios 301 mastering engineer Don Bartley explains the problem and the solution: "As most mastering engineers at the time knew, the Neumann cutting system was designed around stereo classical music and its natural phase/level relationship, in other words as the stereo orchestra played louder there was an equal increase in the ambient out of phase information.
"The Neumann lathe would see this increase in level and phase (particularly the bottom end) and adjust the depth and pitch of the groove to accommodate the modulation of the signal, avoiding "light" grooves and "groove jumping" on playback. However, the Neumann system was not user friendly to loud rock/pop music etc whose bottom end signal was practically mono, resulting in the lathe maintaining a constant depth groove no matter the level of the signal. This resulted in what was classified by the pressing plants as a "dangerous" cut that would "groove jump" on cheaper playback systems. So most engineers did something to overcome this problem.
"Prior to my days at EMI I was mastering records for RCA Sydney and developed a system whereby a phase shift was introduced to the bottom end of the lathe control signal resulting in a level to depth relationship resulting in a "safer cut". The clever people at EMI decided to re-design the control circuitry of the Neumann lathe and replace one the PC boards with their own "Maxicut" board. This created a sensation and engineers around the world were peering into their microscopes to see what was going on.
"By the time I joined EMI in 1980, "Maxicut II" had been introduced, a more refined version and the one we used throughout the eighties and into the nineties. "Maxicut" was definitely the best and most transparent solution to what was an annoying problem with the Neumann cutting system and I believe there was a patent on the design however I'm not sure if "Maxicut" was adopted by any other users."
In Studios 301's March 1980 Report on Technical Developments, the process was described in greater technical detail:
METHOD
The standard Neumman disc cutting chain; the VMS-70, its associated rack, pre-listen tape machines and electronics are designed to cut a groove of typically 25 microns depth. Of course this depth will vary on stereo program and this is aptly known as vertical information. In order to control the minimum and maximum depth of the groove, Neumann takes the prelisten program and derive a control signal which is delayed in time to correspond with the program chain. This control voltage limits the depth range of the cutterhead. However the Neumman system of depth control works only on vertical information.
Our investigations have shown that high level mono signals or lateral information need additional groove depth under certain frequency/amplitude conditions to assure optimum tracking. The Maxicut system is a dynamic control system that only increases the groove depth during that portion of the lateral information that requires additional depth for optimum tracking.
Maxicut also includes a method of improved cutterhead suspension control by use of a "negative output impdeance" amplifier. This allows more accurate control over the mecahnical movements of the cutterhead, as well as Improved low frequency response. The heavy fluid normally used to damp the the natural mechanical resonance of the cutterhead can be reduced or removed.
Other than this negative output impedance cutterhead control amplifier, Maxicut does not alter the standard vertical cutterhead control. We are currently investigating a 20 micron groove depth with Maxicut to improve program length without lower operating levels, or for a given playing time, to further increase levels on disc (however our current levels are probably as high as most modern replay equuipment can handle).
SYSTEM
From the stereo pre-listen chain a left + right (lateral) and a left - right (vertical) signal is derived. Maxicut takes the lateral signal and equalises it to provide a signal representing constant amplitude to frequency in respect to lateral deviations of a groove. The signal is than delayed to correspond in time to the signal from the priogram chain of the disc cutting system.
This signal is then fed to a threshold and shaping network. This network has a signal threshold level and pre-emphasis curve that directly corresponds in amplitude and frequency to the overload point of trackability of a reference turntable. This signal is then rectified and combined with the output of the Neumman vertical information depth control, and a control voltage for the for the control of the cutterhead suspensions is derived. Whichever of the lateral or vertical depth is greater determines the cutterhead depth.
RESULTS
Our results have been very encouraging. We have very seldom seen a disc cut elsewhere that, given the same tapes, we cannot match or better in terms of level and low frequency response while maintaining trackability on our reference "groove jumper" turntable. [a HMV 3-in-1 system]
Original developer John Schell recalls: "I am the man who developed Maxicut. I actually started working on it in 1977, and had a prototype system working by early 1978 with the final boards fitted in late 1978. It was used on the VMS70 in our Mastering Room 3 - MR3. MR1 never had the Maxicut boards fitted as it had the old VG66 rack and then the SX68 cutter head. MR1 was only used for old releases or lesser quality releases. Once I had proved the system worked, it was almost always used for cutting discs, even 7" and 12" 45's. EMI applied for a patent on Maxicut and only released information on it in 1980 once the patent was granted. Basically, the system allowed the cutting engineer to start with a small groove (40 microns) and the system would increase the width of the groove when heavy bass was present in the music. It helped dramatically with dynamic music, and I recall doing a test cut on heavy metal music and found I would increase the level of the cut by less than 1db with this music which is to be expected as the VU meters hardly moved from 0VU. The deepening of the grooves was determined on an old record player with a crystal cartridge as these were the machines which would groove jump if the groove was too small. I did check with other similar type record players too. It is a pity we had to accommodate such "lousy" record players at that time."
The initial Maxicut system did have one issue: under certain conditions, it could cut extremely deep grooves, which could cause non-fill problems in pressings if not detected. Mastering engineer Richard Mott reportedly hit the aluminium substrate a couple of times, breaking the cutting stylus! This was rectified with the circa 1981 implementation of Maxicut II.
Almost all lacquers cut at Studios 301 were produced using the Maxicut process, including all post-1978 Beatles releases and recuts up until the DMM masters in November 1988. Although the Maxicut stamp was applied to the deadwax on earlier pressings, Studios 301 stopped using it at some point in the early 1980s, as lacquers were occasionally damaged during the stamping process.
The only time Maxicut was generally switched off was for the occasional long classical side, where the priority was to maximise the available space during very quiet passages of the recording.
Maxicut pressings remain highly regarded by many collectors and members of the music community, particularly for their combination of high cutting levels, strong low-frequency response and reliable trackability.
Footnote: Phonogram, later PolyGram, sent a memo to EMI (Australia) insisting that at least 80% of the playing surface be used regardless of program length, arguing that customers "wouldn’t be getting value for money" if there was too much unused vinyl!