We Lathe Trolls are always proud when one of our own gets some much-deserved media attention. Here’s an awesome article and video about Mike Dixon, often known around here as “piaptk” (“People In A Position to Know”). The video spotlights his contagious exuberance, his passionate supercool-geekitude about record-making, and his beautiful and unusual individually cut records. It shows off his ridiculously extensive collection of Presto 6Ns, each with an attractive new carrying cabinet. And, it contains an unusually succinct and understandable explanation of just how record cutting works.
(We will therefore forgive the fact that the article link uses the horrendous and incorrect term “vinyls.”)
This month Mike is cutting records in Paris with Kris Dorr, for Converse. I am hoping they will post some blog items of their own, but in the meantime, do read this.
I visited AudioGeography’s Tyler Bisson in Bethel, Connecticut, USA, and we compared his two 1940s-era Presto 6Ns record cutters, which are separated by 2420 serial numbers.
They are not the same. So we geeked out on the differences.
Our man Kris Dorr (aka Kris D) of Washington state is one of our Presto 6N experts. He wrote me after I posted the video and expressed that he wished he could overdub a response track. I wish he would, too! Apparently we got some historical stuff right, but a few of our hunches are wrong here. As with many on this forum, we are often shooting in the dark, doing our best to recapture knowledge which is on the verge of getting lost. The nice thing about Presto 6Ns is that they can work great even if you don’t use the equipment quite in the way it was originally intended. For example, several on the forum (including Tyler and Mike Dixon/piaptk) use them to emboss, which works great even if it isn’t their original purpose.
The best introduction to the history of Presto record cutters is on Alan Graves’ terrific site:
In Part 2 of my visit with Tragwag aka Tyler Bisson, we take the platters off and talk about some adjustments to the idler wheels which might improve the torque and speed of your Presto system. Among other things.
We at the Secret Society of Lathe Trolls are proud that one of our recent members, Andrew Turney (aka Gyro on this site), with his team at Gyro Constructivists of Aukland, New Zealand…
…was responsible for last year’s technological stunt, the Beck’s “Edison Beer Bottle” Cylinder Record. That is to say, it is a glass beer bottle that is also a playable audio record, much in the manner of Edison’s cylinder player. The latter of which, as you might know, was the earliest invention that recorded playable audio (circa 1877).
The chat thread in which the process’s evolution was discussed and reported on can be found here. We were honored to be asked to be a part of the virtual roundtable brainstorm discussions on how best to approach this challenge. It is unclear as to whether or not our input actually played any significant role in Gyro Constructivists’ eventual triumph, but a triumph it was, and a fun one.
What follows is Gyro’s summary report, which appeared previously on our site here. (The creative agency which hired Gyro Constructivists was Shine Limited.)
The Making of Beck’s Edison Bottle Andrew Turney, Gyro Constructivists
Having seen footage of a hard drive
actuator arm play music, when connected to an amplifier, convinced us we
could invert the process and use the actuator as the cutter head once
we mounted an appropriate cutting tip. Effectively, reverse engineering
from the digital realm to create an analogue result.
Other factors in that influenced our approach –having spoken with other cutters and scouring the web– included:
Cutting a mono recording; this allows for higher output levels with less chance of the stylus skipping in the deeper frequencies.
Coating the bottle and all our test platters and cylinders with nitro-cellulose paint, as has been the industry standard since the 1940’s, rather than cutting directly into a solid substrate.
Utilising a small engineering lathe, we retro-fitted a speed controller that precisely locked the the rotational and tracking speeds of the cutting arm.
Cutting head and arm: We stripped 8 hard drives down to ascertain the most appropriate actuator for our application.
The
arm from a 4″ drive as opposed to a 2.5″ drive allows more current,
resulting in greater amplitude; this equals higher volume.
We built three versions of the cutting head, gaining improvements at every step.
A Google search revealed a patent listing
that confirmed the problem of an audio dropout at around 8khz, due to
harmonic resonance, introduced by the mechanical clamping of the tiny
bearing between the arm and drive housing. We eliminated the bearing
altogether, replacing it with a machined piece of flat aluminium clamped
to the head between thin rubber shims.
The Cutting tool Initially,
following advice, we used a standard stylus as used on 78rpm
recordings, being three times bigger than the later microgroove, keeping
the engineering out of the truly microscopic realm. But we were not
getting a good retrieval of the upper frequencies, so we opted to use a
microgroove cut. This also gave us a little over 3 mins of audio onto
the bottle, rather than less under 2 minutes with a standard groove.
Also the downforce is much less, resulting in less heat input to the
cutting tip and less current required. The coils on the head were
smoking in some tests!
We ground a high-speed steel cutting tool
which we polished to mirror finish, resulting in a very quiet cut… all
this taking place under a microscope! We also have a couple of
sapphire tips which we used for some test cuts, but we found the steel
one are quieter but with a much shorter life. In fact any contaminants
in the coating would take a microscopic chunk out of the tip effectively
destroying it!
Heating the tip by winding hair-thin NiChrome wire and passing a current through it resulted in a smoother cut, requiring less downforce and reduced surface noise, as it helps it glide through the surface without tearing the substrate. Every time the downforce, cutting speed or heat adjustments were made, recalibration and equalization of the audio was required. Many days were spent resolving this.
Surface Substrates and Coatings Initially
we cut onto polycarbonate and acrylic to test the feasibility of using a
hard drive actuator. This proved the principle but a lot of surface
noise was present. We spent the first few weeks of test cuts onto
acrylic platters, coated in Nitro-cellulose, mounted on a high torque
custom built turntable.
Clear nitrocellulose was successful once a the correct amount of castor oil was established, again through trial and error. We continued with this formula thoughout the remainder of the project.
Sound Engineering Using
Garageband, we applied the RIAA equalisation curve, a filter that
reduces the low frequencies and increases high frequencies. This is
reversed by the phono input in playback through the amplifier. Further
equalisation was needed to cancel out resonances and harmonics
introduced by the cutting head and arm. Tone Sweeps of 50hz>5000khz
were used for the test cuts, allowing us to adjust the equalization
throughout the frequency range.
We cut scores of tracks in the quest for
the greatest dynamic range and least amount of surface noise, monitoring
through 15″ Tannoy Moniter Gold speakers.
Cutting the Groove Many
of the above developments gave us incremental improvements to upper
frequency ranges, but we achieved a big improvement by recording at a
quarter speed, and subsequently 1/8 speed. This way the cutter head
didn’t need to achieve these high frequencies in real time in order to
cut them onto the record. Consequently the cutting time for the track
was a very tense 26 minutes.
Using small tube mounted close to the
cutter, we vacuumed away the swarf as it peeled off the surface; should
it come in contact with the hot cutting tip, it would instantly bake on.
To
control the actuator’s movements, damping was attempted with various
materials; a more powerful spring was able to temper the actuator’s
large movements without reducing fast ones. This introduced resonances
and harmonics which were removed prior to recording by software
equalization.
We experimented with damping the cutting head
initially with blue tack (as Gum was used in the middle of the last
century). We then mounted a silicone oil filled trough to the arm with a
paddle attached to the head and later to the arm itself, this being
easily tuneable by adjusting the size of the paddle and viscosity of the
silicone.
Adding up to a kilo of ballast to the cutting arm made further improvements.
We
also mounted a cartridge to the end of the cutting tip to monitor the
audio as was cut real time, also allowing us to compare the difference
quality between the cutter and the resulting groove when played back.
Each
cut was scrutinised under a microscope to inspect the smoothness and
profile of the groove, and to check the cutting tip for damage.
The Player Once
we had the final bottle with it’s audio track cut into the surface
coating we designed and constructed a player from black acrylic sheet,
laser cut from a file drawn up in the 3D.
Much of what we learned through the build of the cutter we applied to the player. Special attention was made to eliminate any unwanted noise being introduced by motor noise, bearings and resonances from the tone arm and casing of the player itself.
The Edison Bottle made its public debut at
SemiPermanent in Auckland in May to a standing ovation from the
assembled media and design community.
Credits to: Andrew Turney, Rob Askew & Tom Beeston – Gyro Constructivists John Baker – Real Groovy Peter King – Lathe Cut Records Fred Koke – Retrotronics Auckland Brian Harris and Chris Davison Robert Stebbing – Stebbings Recording Centre
In February 2013, Leandro Gonzalez of Stereodisk drove me to Elizabeth, New Jersey, USA to meet Desmond of Mastercraft Metal Finishing.
As many who hang out at Lathe Trolls know, Mastercraft has an eosteric specialty: They make the metal stampers which are used to press vinyl audiodiscs.
After an acetate-based master record is cut on a record lathe lathe, it is sent here, and then the magic begins. (After Mastercraft creates these stampers, they are sent to any number of pressing plants around the world, and vinyl records are produced. But that’s the next step…Mastercraft doesn’t press records.)
As of 2014, they’ve been in business for 30 years, and I do believe Desmond’s run at Capitol Records preceded that for a significant duration. I’d love to follow this video up with a proper interview of Desmond’s career and get that story straight.
Desmond, Walter and Izzy took time out from their day to show us how the process works. Enjoy!
(Our man Serif will be pleased that Desmond confirms in the video that the proper name for this process is electroforming, not electroplating. Touche.)
http://www.MastercraftRecordPlating.com/
Mastercraft Metal Finishing
801 Magnolia Ave.
Elizabeth NJ, 07201
Phone: (908) 354-4404
Fax: (908) 354-4405
