I’ve Googled this a bit and sho’ nuf you too can own a no-touch record player…for the price of a decent mid-sized car.
Why so expensive? In an age when a new CD player can be acquired for less than the cost of a phonograph needle?
lack of critical mass? … if only 100 CD playes would be sold worldwide - they would also be quite expensive
cheers
alfred
But needled players are still produced and available. A laser guided stylus & processor could be added for a nominal cost and would easily annihilate other players commercially even if it were $10 more.
It’ll never be competitive with low cost optical scanners that can accomplish the same thing;
sort of, if you squint real hard while listening to the mp3’s.
Not sure what you mean by “laser guided stylus” (is there still a needle?). Anyway, assuming we’re talking about a laser alone reading the information in the grooves, I doubt there’s any market for this at all, because you’re digitising the signal, and the main reason some people are still buying turntables is because they like the “warm” sound of the pre-digital technology. Some might be attracted to it because they can play their rare vinyl repeatedly without any wear, but then they could just copy them to CD.
DJs, maybe.
Who is to say that the laser is digital?
I remember reading about this. I seem to remember that the laser was analogue, reading the wiggles in the groove walls by some kind of interferometry. It had to be a lot more exacting, and a lot less noisy, than a laser designed to read two well-differentiated reflective states that would be converted to a digital signal.
The analogue laser would have to distinguish the different wiggles in thetwo different groove walls, as well as possibly the differing depths of the groove. To get a set of multichannel output voltages that was an exact analogue of the shape of the groove walls would seem to me to be quite difficult.
If the laser pickup was indeed analogue, that would explain a lot of the expense.
Google found it: the ELP Laser Turntable. It’s completely analogue. It uses a separate beam to read each groove wall, with additional beams to track the groove.
And yes, it is the cost of a car: $15,000 US.
I want one. 
Completely analogue? I stand corrected. Cool stuff!
I recall that similar techniques have been used to replay delicate early recordings, in particular old wax cylinders. Apart from the total lack of wear, another big advantage is that the laser can read the less damaged wobbles in the very bottom of the groove - those that have mostly escaped the scratchings of a stylus.
I concur that this is exceptionally cool.
Part of the expense has got to be the tracking. In OS turntables, the stylus and arm were guided by the groove itself, physically. You just laid the needle in the track and the table turned. Sometimes the distance between groove, side to side, varied–like between songs, so someone could see where the start of the song was.
Some of the original players were just a needle on an arm, with a sounding board for amplification.
…and to go with your laser turntable, we have the Vestax VRX-2000 Vinyl Recorder. Now you can dub all those old CDs and MP3s and WMAs to LP-R. Eliminate the hassle of format conversion and brittle playback software!
I’m not sure how they get the whole sound output stage to be analogue.
I did some related work at university, using laser interferometry to pick up small vibrations and convert them back into sound. Using a similar technique to track the sound waves set into a record groove would be feasible, I think.
Our setup was basically a Michelson Interferometer with narrow light detectors mounted in the surface that the interference fringes were projected onto. One arm of the rig had a fixed path for the laser, the other bounced it off the object having its motion measured.
As the target object moved the interference pattern would change causing the fringes to scan back and forth across the light detectors. The captured output was a dense series of alternating peaks and troughs with a frequency proportional to the derivative of the driving waveform. In the test setup we fed the data to a computer and used a program I’d written to reconstruct a digital copy of the original waveform.
My analogue electronics aren’t up to much - assuming the record player works in a similar manner can anyone confirm whether it might be possible to reproduce the audio using purely analogue components?
CDs were designed from the beginning to be played with lasers. LPs (and other grooved records) were designed to be played with styli, and present technical problems for laser playback that don’t exist with CDs. For example, there is no standard groove pitch for an LP (the groove pitch is the amount the groove moves laterally for each revolution of the record) - where the groove walls hold a stylus in place regardless of the groove pitch, with laser playback there has to be some method to make the laser follow the groove. The same is true for following the lateral modulations of the groove - the groove walls will cause the stylus to move laterally, while with a laser system something has to detect and follow the lateral movement. CDs don’t present the same challenges to laser playback - the system is designed to give a clear indication of where the “groove” is, and the signal is encoded as changes in reflectivity in the “groove”.
The optical system for playing back damaged cylinders is different from that used by the ELP turntable. It’s being developed by Dr. Carl Haber at Lawrence Berkeley Laboratories in conjunction with the Library of Congress. Dr. Haber’s system basically takes a picture of the record and produces a digital signal from it. It’s not an analog playback system, nor is it designed to work in real time. The object is to enable the Library of Congress to digitize all the records in their collection, including ones that are too damaged or fragile to be played by conventional means.
Dr. Haber is actually working on two related systems - one for playing laterally modulated grooved records (e.g. LPs, 45s and 78s) and one for playing vertically modulated records (e.g. cylinders and Edison Diamond Disks). Yes, the grooves on cylinders move up and down, not side-to-side. For vertical records, Dr. Haber developed a system where the groove is illuminated with white light and photographed with a lens that deliberately has a lot of chromatic aberration. The aberration causes the colors to focus at different distances from the lens - he gets a photo where the color tells what the depth of the groove is at each point. Clever!