EMI Australia's MAXICUT Process

[Aussie0zborn]

Back in the heyday of vinyl EMI Austraila's "Studios 301" were reknowned for the loudest cuts and by far the preferred disc cutting studio in this country. They used a process called "MAXICUT" (patent applied for). This info from : http://forums.stevehoffman.tv/threads/emi-maxicut-record-mastering-vinyl-cutting-process.102348/page-2

A REPORT ON TECHNICAL DEVELOPMENTS / MARCH 1980 / EMI CONFIDENTIAL

PAGES 57-59

Studios 301

MAXICUT - A UNIQUE DISC CUTTING PROCESS

Maxicut is a name we at Studios 301 have applied to several modifications of our Neumann VMS-70 disc lathes. These modifications are contained on two printed circuit boards which replace the Neumann SV-66-V2 and TE-66 cards.

Maxicut is a process that allows us to cut lacquers at a significantly higher level, typically 6-8dB, without the normal tracking problems that less expensive turntable/cartridge units usually exhibit in trying to track these higher levels (groove jumping). Maxicut accomplishes this with no loss of the program signal and without significant loss in program time.


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, givebn 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.

Note: the "groove jumper" turntable was a HMV 3 in 1 system they tested on for tracking problems.

Source : http://forums.stevehoffman.tv/threads/emi-maxicut-record-mastering-vinyl-cutting-process.102348/page-2

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Hi,

I was a mastering engineer at Studios 301 in Sydney in the early eighties, and used the Maxicut system.

Basically, the maxicut system allowed the cutting engineer to start every cut with the same minimum groove width of 40 micron, and depending on the (1) loudness and (2) the phase of the program, the maxicut would control the lathe and would drive the stylus deeper to accomodate those two parameters.

This was somewhat different to the standard neumann procedure of starting the cut with a wide (i.e. deep) enough groove to deal with the vertical motion on out-of-phase. The standard unit didn't vary the groovewidth very much based on level, just the groove-spacing. Usually (with a standard VMS-70) the starting groovewidth was something like 60-80 microns, and vertical limiting or elliptical equalisation was applied to control the vertical excursion of the cutting stylus.

In short, it meant that in quiet passages the grooves were thinner (shallower), and in loud passages and or out of phase material it would be automatically made wider to compensate. This usually resulted in a cut 2dB or so louder than a standard system, and perhaps more on classical. Or you could cut a side withoud ending near the inner diameter, meaning less hf loss and tracking distortion.

I know that for a time there was at least one lathe at EMI NZ that had maxicut fitted, as it was later sold to CBS-Sony (as it was then) while they were still in the Waltham St premises in Artarmon, and I saw it there with Maxicut & a Zuma computer fitted to it. I don't know where it went after that.

BTW my cuts had Otto or OR scribed near the matrix numbers (along with whatever the client wanted scribbled onto it).

I hope that clears up some of the mystery.

Cheers,
Otto Ruiter
Sep 4, 2007

===============================================

Ok, so I wrote to Don Bartley and he has replied What a nice guy! This is what he had to say about Maxicut:

"As most mastering engineers at the time knew the Neumann cutting system was designed around stereo classical music and it's natural phase / level relationship, in other words as the stereo orchestra played loader 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 where by 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 2" 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."

So there you have it! Mystery solved.

paolo, Jan 17, 2007

Source : http://forums.stevehoffman.tv/threads/emi-maxicut-record-mastering-vinyl-cutting-process.102348/

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Of the two VMS70 lathes at Studios 301, one was sent to the factory as a backup to the VMS82 DMM system in the new cutting studio installed there, and the one that remained at Studios 301 was donated to the Australian Government's National Film and Sound Archive once 301 quit cutting vinyl. Edit : The VMS70 from the factory disappeared without trace.

So someone somewhere is more than likely cutting with Maxicut but more importantly can someone come up with this mod?

[Serif]

[audadvnc]

Does the output of the Maxicut circuit drive the cutterhead coils directly or feed some suspension coil that rotates the head and drives the stylus farther into the disk?

I'd think either could work, but directly operating on the coils would allow for more rapid adjustment changes without risking mechanical resonances in the head and arm.

[petermontg]

From my understanding it is a direct to the SA66 from the cards. The components on the 2 cards are changed, nothing else.

[petermontg]

Basicially what it did was change how the preview was seen in pitch and depth.

[opcode66]

Schematics?

[Aussie0zborn]

Todd, if I had the schematics I would have posted them for all to use. This process cut the loudest records known to man. You might try contacting the last poster in that discussion on the SH Forum as he alludes to having contact with the designer of the Maxicut system.

I would suggest it is well worth searching for these schematics. Users of both the standard VMS70 and VMS80 generally agree that the 80 cuts louder than the 70 without playback errors and so Maxicut supposedly becomes redundant if you have a VMS80. As Vinylium's Pitch13 is said to surpass the VMS80 P&D system, then perhaps that's all you need for louder cuts.

In my original thread I mentioned that one of EMI Australia's VMS70 lathes has ended up in the hands of a fellow Troll. That lathe was said to have come from EMI Australia but a careful inspection against the information shown in this thread shows that there are no Maxicut modifications to his lathe. So somewhere out there, there is still a VMS70 with Maxicut modifications.

[opcode66]

Truly fascinating the VMS70 is. The design of the system is so nice and affords for many modifications. I think it is really interesting to hear about what individuals, studios, and labels did to change and evolve their VMS systems.

This particular mod sounds fairly easy to implement. Changes to only a couple cards... That is why I was asking if anyone knew what they were. Seems to me a few components would cost infinitely less than your other suggestion.

I am still tinkering in this realm myself. I collect any and all data possible.

[petermontg]

Schematic???

I think it fairly disappeared along with the other VMS70. I searched high and low for it last summer. I think they could have went to the rubbish tip with EMI. Even if there was a schematic to start with. Am thinking the cutting engineers at EMI were pretty privy to what was on those cards.

Am sure if there is one schematic out there, that person does not want to give up their game.

Best

[Stevie342000]

Just a thought from across the pond, if there is any information to be had it will be with the EMI Archive, it's on their website, you have to go search for it and put in a request, it may cost you money.

EMI Abbey Road would be the only place any of those cards or machines ended up, if EMI wished to keep spares for their cutting machines. They are in the same position as everyone else here in regard to spares for Neumann cutting lathes. Unless of course Neumann make parts for them to order. EMI does not as far as I know have a R & D department any more and has not had one for some years.

It depends how much they dumped of the information, equipment here in the UK (or worldwide)when the Hayes plant or vinyl disc cutting was closed down, it is still operational but most of the area has been pulled down and redeveloped. Take a look on google maps Blythe Road, Hayes should get you there. Some of the Art Deco original buildings may survive in parts if not in entirety.

[Aussie0zborn]

This could be a very worthwhile mod and I would encourage anyone interested to pursue it. Google "Maxicut" and see what Beatles record collectors have to say - some of these people have at least ten different copies of every Beatles album from around and three comments on the Maxicuts are inspiring.

Something we don't read about however, is that EMI's Studios 301 were said to blow up more cutterheads than the rest of the disc cutting studios in Australia put together. But hey, they cut some pretty damn LOUD records that never jumped and were the disc cutting studio of choice for all Australian artists.

Lets keep searching and I'll do what I can at this end.

[petermontg]

That would be great Mike. I shall try the archive.

[petermontg]

Okay, you need to go to the archive in person. You can't request a document to be scanned even if they have it. It's at full discretion of the Archivist. Even if the schematic is there you might not be allowed to scan or view it.

If it is there it might be worth to bring the TE and SV-66 schematics with you. These cards are pretty small so cross reference parts is no issue.

wait and see what my response shall be...

[Aussie0zborn]

Good work, Peter. I just placed a call to my contact there and luckily he still works there. I'll get back to you as soon as I hear back.

While I think about it, if anyone gets the chance, you really have to buy these 12" singles from Australia and you will be fully blown away. Both were cut by DB at Studios 301 (when it was owned by EMI) using the Maxicut process :

1. The Church "Under The Milky Way" on the Mushroom Records label. Australian cut and Australian pressing.
(Not the Arista label that released it in foreign territories unless it's the Australian cut with the initials "DB" in the deadwax)

Not only is this a brilliant song, brilliant recording and production but an absolutely brilliant cut. If all vinyl sounded like this the world would be a better place.

2. Grandmaster and Melle Mel "White Lines (Don't Do it)" on the world famous RCA label. Australian cut and Australian pressing.
(Not the original Sugarhill label from USA).

This is the loudest 12" single I had ever heard and I've never heard so much bottom end on a record. Sure there is a tiny little distortion and too much compression but it sounds like no other record.

[opcode66]

I get what the approach is. I think the mod to the TE is pretty straightforward. You are just adding another control voltage line in to be summed with the other. The V2 card is the one that will give you the difference of L and R preview which is what you need for know Vertical movement. So, it seems they are taking signal from the V2 card and running it through a circuit that:

"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."

The delay time is governed by the speed that you are cutting at (33.3, 45, etc). These delays are created in the PS66 plug programmer (lunchbox). So, if you want to know what resistor capacitor combo to use for each time look at the PS66 schematic. Routing the output from this custom circuit to the the TE in combination with the standard control voltage would be what they were doing.

I think one could replace the proprietary circuit between the V2 card and the TE unit with a simple circuit and an arduino chip. You can do audio signal processing fairly easily. So, the input to the chip is form the output of the V2 card. The output of the circuit could be from a DAC controlled by the Arduino chip. The output would be routed to the TE unit. Boom, Maxicut.

[petermontg]

Cool, Thanks Todd. Boom! indeed.

"takes the lateral signal and equalises it to provide a signal representing constant amplitude to frequency in respect to lateral deviations of a groove."

It's that circuit we really need??

[opcode66]

Yep. But, these days, I think it would be most efficient to do it all virtually. ADC gets you a digital stream. Use DSP for equalization and rectification. Then a DAC for output. You wouldnt even need to use expensive converters because this audio is only for control voltage and isnt recorded to disc as such. They did in circuitry because they didn't have the choice to do it otherwise. Here in 2014, we have the luxury of fantastic computing and cheap off the shelf ADC/DAC.

[petermontg]

both archives, commerical and ponograph do not have any info stored on the lathes or any info on schematics am afraid.

[Phinster]

so I assume this is similar to the adjustable 'mono depth' control on a VMS 80..