Of course it doesn't need to be a microgroove. I think we'll cut as large a groove as we can get away with. Can anybody help me select the largest cartridge that can achieve stereo? As far as I understand 78 cartridges only do mono. Or is that not correct? The schematics I found have 4 pickups inside, so I don't see why stereo isn't possible. I'd love some guidance on this.
Bigger unfortunately gets really expensive, really fast. And we also need to leave some room for us to break the record again.
I don't think using a laser cutter would give the right results. We've got a laser cutter in our shop and I wouldn't call it's output and cutting depth extremely consistent. Also, CO2 lasers are usually pulsed. Fast enough to not bother the cutting, but probably a problem producing audio. Besides, record cutting is a solved problem. We don't want to invent new techniques if we don't have to.
Bigger unfortunately gets really expensive, really fast. And we also need to leave some room for us to break the record again.
I don't think using a laser cutter would give the right results. We've got a laser cutter in our shop and I wouldn't call it's output and cutting depth extremely consistent. Also, CO2 lasers are usually pulsed. Fast enough to not bother the cutting, but probably a problem producing audio. Besides, record cutting is a solved problem. We don't want to invent new techniques if we don't have to.
Really, you should make a contest : get inside the biggest record !
That's a very good question, and I was hoping to see some good answers.
Could be wrong, but I don't think the stereo playback with the big stylus is a problem. Just find a robust cartridge that can take a 78 stylus. Maybe a DJ cart that also has a 78 stylus available. I use an old Stanton 680 that will take either a microgroove or 78 stylus. Works well with the heavy wooden tonearm I have.
It's the cutting that might be difficult. You'd want a stereo cutter with a 78 stylus.
As I mentioned, you can get a 78 stylus for many standard stereo cartridges. Your problem may be finding a stereo cutter that will cut a 78-sized groove. But surely the people on that other forum can tell you whether you can do that.
The guy helping with the cutting has a scalable 3D printed solution for a stereo cutting head. It's rather clever. If you're curious about his project: The Secret Society of Lathe Trolls • View topic - Deep Grooves Mastering - Project Bladerunner
He's got a source for custom cutting styluses, so I think we're in a good place.
Right now we're getting closer on the design and we're starting to order parts. Photos soon...
He's got a source for custom cutting styluses, so I think we're in a good place.
Right now we're getting closer on the design and we're starting to order parts. Photos soon...
Since big platter would put pressure on bearing wouldn't it be good if light, stiff material be used for platter. or a light wood sandwiched between aluminium plate ? For Heavy platter I think magnet rings can also be used to ease the pressure on bearing. Presuming this would be belt drive, which motor will be used ? Would using two motor benefit if they share the load ?
Would be cheatin', but suppose you just draw a virtual groove with a ballpoint pen?
Surely not that difficult to have a robotic pickup follow the groove. Don't even need
to "spin" the record, thus truly absurd physical size is not limited by any turntable.
For "cuttting" the initial spiral, robot might be leashed to a string that winds on a post.
Even if you do cut a real groove into a real record, the record might not need to turn.
Surely not that difficult to have a robotic pickup follow the groove. Don't even need
to "spin" the record, thus truly absurd physical size is not limited by any turntable.
For "cuttting" the initial spiral, robot might be leashed to a string that winds on a post.
Even if you do cut a real groove into a real record, the record might not need to turn.
The original cutter like Neumann cuts first the some DuPont foil?
then adding the some metallic solution at the surface of plastic foil
after that they making the moulds or something...
But That gear is huge and pretty heavy
.
You can find some infos in Gotham radio PDF scanned magazines from 50" and 60"
then adding the some metallic solution at the surface of plastic foil
after that they making the moulds or something...
But That gear is huge and pretty heavy
.
You can find some infos in Gotham radio PDF scanned magazines from 50" and 60"
Building a big turning thing isn't the problem. I fabricate things for a living, and a big turntable is right in my wheelhouse. In fact, I built slightly comparable, slow turning thing:
The wackywire was designed to slip very easily to prevent injury, but the premise is the same. We'll use bushings instead of bearings, so there's less vibration. The motor will be a 1/3hp motor that we can easily control with a speed controller to dial in the RPM. We'll be stepping down the RPM with two stages of pulleys as well.
The steel is on its way. I'll be able to post photos of the build soon.
An externally hosted image should be here but it was not working when we last tested it.
The wackywire was designed to slip very easily to prevent injury, but the premise is the same. We'll use bushings instead of bearings, so there's less vibration. The motor will be a 1/3hp motor that we can easily control with a speed controller to dial in the RPM. We'll be stepping down the RPM with two stages of pulleys as well.
The steel is on its way. I'll be able to post photos of the build soon.
the arm will weigh a ton! You'll need a beyond stiff suspension to have it work.
Why worry about groove dimensions and spacing? Build an oversized cartridge with 2-3X normal dimensions. It won't be very hi-fi but it would certainly satisfy the requirements!
I imagine you could make a very simple transducer out of an old Victrola pickup, with a magnet & coil, OR just mount a conventional MM cartridge so it's excited & coupled to the Victrola pickup.
The disc? I'm leaning towards finding an enlightened machine-shop. Download the audio file and engineer a screw drive across the disc with a very energetic backwards engineered copy of your pickup.
And, pray no one turns up a giant disc and Victrola or Edison machine built 100 years ago as a promotional ploy!
Why worry about groove dimensions and spacing? Build an oversized cartridge with 2-3X normal dimensions. It won't be very hi-fi but it would certainly satisfy the requirements!
I imagine you could make a very simple transducer out of an old Victrola pickup, with a magnet & coil, OR just mount a conventional MM cartridge so it's excited & coupled to the Victrola pickup.
The disc? I'm leaning towards finding an enlightened machine-shop. Download the audio file and engineer a screw drive across the disc with a very energetic backwards engineered copy of your pickup.
And, pray no one turns up a giant disc and Victrola or Edison machine built 100 years ago as a promotional ploy!
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