33 1/3 gramophones?

[AnimusDivinus]

hey... i like antique things, even if theyre just replicas of such. i just like the designs of many older things

so im curious, is it possible to get a replica gramophone with crank handle to play 33 1/3 rpm records?

[Chris Daly]

Make your own, but sticking to 33 1/3 might require a steady hand. Interestingly yesterday on radio National here in Australia there was a person at Birdsville a remote area close to the borders of Qld Sth Aus and WA who was discussing a wind up gramaphone with no power
other than the end users hand. He demonstrated it playing. The Audio was reproduced from the needle via piece of cardboard that apparently had the best quality to vibrate the air. You could certainly hear the record playing.
The link to hear that program is here: The Birdsville Working Museum closes its doors - Bush Telegraph - ABC Rural (Australian Broadcasting Corporation)

Cheers / Chris

[AnimusDivinus]

i was referring to buying a replica with the big brass horn on top, and maybe tuning or replacing the spring motor mechanism to turn it at 33 1/3 rpm

[aardvarkash10]

But why?

Seriously, the whole concept of recording changed between mechanical and electromechanical reproduction.

If you were going to use a mechanical reproducer to play a "modern" RIAA equalised LP it wouldn't be capable of equalising to match the equalisation curves, resulting in incredibly tinny sound.

This without the consideration of the difference in recorded signal amplitude between records made for mechanical reproduction and later stuff made for electromechanical.

Could it make a sound? Sure - I did it as a kid with a hand-turned platter and a length of cane with a sewing needle at one end and a cardboard cone at the other.

Not surprisingly, it sounded weak, tinny and thin.

[counter culture]

Gramophones played '78s' (also called shellac records) which were made of a hard, frangible material. They used a 'needle' to run in the groove. This was an exceedingly sharp steel spike of about 1/2 ~ 3/4 inch. The records ran at 78 rpm partly to produce sufficient energy to excite a semirigid diaphragm (in some purely acoustic designs) which formed the narrow termination of a horn (often approximately exponential), and to which the needle was clamped. The horn had a hinged joint permitting a short section to rotate to permit placement of the needle on the record and a further mechanical arrangement permitted the needle to track the groove. The downforce was on the order of ounces. Any attempt to play a vinyl record on such a device would, in my opinion, result in its destruction for any other purpose in the space of a single play, and probably for even that purpose in a short space of time.

[Pano]

True all of the above, but I've always fantasized about a purely mechanical LP playback.
Could it be done with modern materials and engineering? The RIAA curve could be the biggest stumbling block.

Far beyond my build skills, but a nice daydream.

[eyoung]

I own a Victrola schoolhouse model with a crank and it was made for shellac recordings. I also own vinyl 78 rpm recordings that were made for ceramic cartridges with stylus assy' more similar to more modern vinyl and do not play these on your old Victrola as one play is all you will get...

Regards, El

[counter culture]

You want stereo?

I'd start with a traditional stethoscope, dismantle that and go from there. You could use 2 carbon fibre tubes to make the tonearm, one for each channel. You need a pivot that will permit individual connections to each channel but still rotates freely . Then you need 2 acoustic transducers each @ 45 degrees to generate the sound from the stylus motion. Maybe a piston type actuator with an acoustic impedance transformer? Hmm. Maybe a mylar diaphragm is easier. RIAA might not be impossible but you've got very little volume to work with to create an acoustic filter.

Now look at the rubbish you've got me writing...

:-)

[Pano]

Seeee?

[indianajo]

Stay with 78's, the source disks are out there for $1 each. My Bozo the clown record player pleased me endlessly in 1953; It had a cardboard diaphragm in a finger length diameter bakelite housing. The radius of phonograph needles was quite visible, not as sharp as the diamonds on LP's. Of course, I have higher standards of frequency response now. But Tchaikovski's "Sleeping Beauty" on 78 RPM- very scary to a 4 year old. The pin prick came at the end of side 1. You had to flip over to side two for the prince kiss part, if you dared.