No touch record turntables *update*

I had one of those cascading thoughts streams yesterday, It would be great to have a record turntable that did not have a stylus. The music grove would be read optically and translated into the music stream on the fly. There would be much less wear on the record and the signal could be manipulated to remove any distortions.

After about 30 min I had some ideas sketched out. First the name would be C&P audio using the initials of me and best audiophile friend :-)  The cartridge could be linear tracked like my fav B&O deck hovering just above the plane of the record surface.  The detector signal could be fed to a small processor below the play deck for interpretation. A few of ideas rapidly followed ..

• Speed of track optical processing is well within the scope of modern processors (like self driving cars)
• Lighting and video capture via optical link to head (like an endoscope)
• Track detection and linier tracking across record - controlled by feedback from the cartridge (like a 3D printer)
• Surface height tracking possible over warped records
• Scratch detection and skipping, long view, short view
• Digital or analog output
• A dust removal system would be needed to replace the stylus pushing debris out the way either by blower or electrostatic.

Then of course I had to Google the idea to find what else is out there .... Looks like only one vendor ELP Laser in Japan has the pure light/laser version I was thinking about. Two other vendors offer cartridges with optical movement interpretation. The Minot has a full deck with optical tracking and arm movement, with DS Audio offering a cartridge than can be deployed on a tradional deck with replaced signal electronics.

Key Technologies for Optical Playback

• ELP Laser Turntable: The most prominent, and essentially only, commercially available option is the ELP Laser Turntable. It uses lasers to read the groove modulation and converts the reflected light directly into an analog signal. It is fully contact-free, meaning no damage is caused to the record, allowing for high-fidelity sound from worn vinyl. Being a made to order unit the cost is high. 
  
  
  
  
  
  
  
• Miniot Wheel 3: This modern, minimalist, and versatile player also features an optical pickup system rather than traditional magnetic coils. It uses a stylus to scan the groove but has optical transducers to create the signal. Claiming to be gentler on records while providing a "perfect" analog sound from 0 Hz.
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• DS Audio Optical Cartridges: A different approach, DS Audio produces optical cartridges that can be installed on traditional high-end turntables. They use an LED light and a photo-sensor to detect the movements of the stylus, rather than magnets, which they claim reduces noise and improves tracking.

Given the available technology of arm tracking control from a 3D printer and improved speed of processing available in a Pi 5 there could be room for a cheaper all optical turntable. The development costs and effort would however be substantial. Probably stick with the B&O deck for now. 

Down this internet rathole technolgy based search came across this interesting items about dust repelling surfaces research at NASA. 

Update 5/4/2026

Some ideas just won't let go, here are some more notes on the subject. 

How fast would you have to read a record groove at normal playing speed ? The answer depends on where on the record the needle is. As rotation is constant, at the outter edge the needle has to move faster than in inner part of the record to maintain the contant RPM. When it get to the run-out area, next to the lable, the circumference is smaller therefore the needle is moving slower in the grove to maintain the same rpm.

On the outer edge of a LP playing at 33 rpm the needle travles about 0.5 meters per second. At the inner edge of the same LP the needle is moving at 0.2 meters per second. The range of speed is less for a '45 but within the same scale.

Using a small handheld USB microscope camera we can see some images of a '45 revealing scale of the optical issue.

Ninyoon Full HD 1080P USB Digital Microscope Camera for iPhone/iPad Android PC, 50-1000X High Definition Portable Handheld Microscope with Light 

Groves by the inner run-out area showing a track gap or quiet section

Groves are spaced at about 8 to the mm. Shown against a mm ruler.

Dust and debris can be present

Label overview

Lable at same magnification

The project would need better optics to have a chance to read the groves at a reasonable level of accuracy. Also the tracking of grooves would need to be +/- 0.1 mm. 

It might be possible to scan a field of group of grooves for a revolution and stitch the tracks together in sequence to recreate the whole track. However if the groves were missalligned or stiched out of order, the result would sound like a scratch.

More record format information from over at Breed Media

Vinyl Record Size Chart

The chart below shows the playing time for different record sizes at both 33 RPM and 45 RPM.

Record Size	Minutes per Side at 33 RPM	Minutes per Side at 45 RPM
7-inch	7:00	5:00
10-inch	13:30	10:00
12-inch	19:30	14:30

and 

How Do Different Play Speeds Affect the sound of Vinyl Records?

There are two important parameters that affect the sound quality of a record which are both set when the record is cut. Firstly the speed and secondly the gap between the grooves which is determined by the playing time. In simple terms the higher speed of 45rpm provides better sound quality than 33rpm as there is a longer section of the groove to hold each second of audio. This is analogous to the sample rate of digital audio. But it's not that simple! The outer edge of a 12" record travels at more than twice the speed of the runout groove near the label so in theory the audio quality is gradually decreasing as the record is playing.

Equally as important is the space between the grooves. The louder a source recording and the more bass the greater the lateral vibration of the cutting needle and hence the width of the groove itself. It is possble to extend the playing time by reducing the volume and attenuating the bass but this reduces the quality.

The 45rpm 12" single developed in the 70's would often have only one track per side and made the most of vinyl limitations to get the maximum dynamics and quality available. Ultimately the standard 12" LP album at 33rpm is a compromise between sound quality and the playing time.