Turntable resonance

[Daithi]

Neat! Good luck with it; I am very curious what it will look like.

As a rough notion its a bamboo breadboard inside a Pelican case with an HMV32 motor and a PVC horn attached. The horn is underneath, so essentially its a portable.

[Marco Gilardetti]

How about a sandwich of carbon fiber and some heavy material?

Definitely worth trying out, at least in theory. In practice, copper platters are extremely scarce, occasionally handcrafted in small numbers, and usually cost a half fortune. I've never really seen one mass-produced. Usually they're also too heavy compared to the orginal rubber platter, which poses questions about the long term mechanical integrity of the spindle, motor stress, etc. Add to that the fact that copper is very easily oxidised and looks awful if not polished daily/weekly, and you'll get a picture of the reason why I never really felt compelled to try it out.

[Daithi]

Definitely worth trying out, at least in theory. In practice, copper platters are extremely scarce, occasionally handcrafted in small numbers, and usually cost a half fortune. I've never really seen one mass-produced. Usually they're also too heavy compared to the orginal rubber platter, which poses questions about the long term mechanical integrity of the spindle, motor stress, etc. Add to that the fact that copper is very easily oxidised and looks awful if not polished daily/weekly, and you'll get a picture of the reason why I never really felt compelled to try it out.

A laminate of rubber in the middle and carbon fiber on the outside with the top and bottom carbon fiber layers electrically connected at the edge ?

[CarlosV]

Well, my take on this is that the "improvement" has little or nothing to do with resonance, but it's instead due to the fact that copper is a conductive material, that quickly discharges to ground static electricity.

Marco, deviating a bit from the main subject, I use in one of my (modern) turntables a dust cleaner arm with carbon fiber brush, and with a wire that connects to the turntable ground. It is a pretty effective remover of dust and static electricity out of the record surface. I think these are still for sale, it is made in the UK.

[AudioFeline]

... Add to that the fact that copper is very easily oxidised and looks awful if not polished daily/weekly, and you'll get a picture of the reason why I never really felt compelled to try it out.

A spray of polyurethane (or something similar) will prevent the polished copper from oxidation.

[AudioFeline]

there's today's extravagant person who say he listens with a copper "mat" [on an electronic turntable] and reports "improvements" in sound quality.

Well, my take on this is that the "improvement" has little or nothing to do with resonance, but it's instead due to the fact that copper is a conductive material, that quickly discharges to ground static electricity...

The posts I've read discussing improvements using a copper mat on an electronic turntable seem to focus on the sound quality rather than using the mat to discharge static. For static to discharge it needs to connect with something grounded. A wire connecting the copper mat to the turntable or power ground would do this, but if this isn't available it could discharge to a person with a zap!

[Marco Gilardetti]

A laminate of rubber in the middle and carbon fiber on the outside with the top and bottom carbon fiber layers electrically connected at the edge ?

It would be nice to try many things, if only a decent way to cut precise circles at home had been devised. Even factory-cut mats most of the times are an offense to the eye when seen revolving.

Marco, deviating a bit from the main subject, I use in one of my (modern) turntables a dust cleaner arm with carbon fiber brush, and with a wire that connects to the turntable ground. It is a pretty effective remover of dust and static electricity out of the record surface. I think these are still for sale, it is made in the UK.

Hello Carlos, thank you, I already use one of those.

[audioengr]

I plan to cut one of the 25 pound lead bricks I have into smaller pieces and put two into the bottom of my Victor II. I will report back on the result. I already have dampening material glued to the top of the box, under the turntable, since the lid is only rigidly attached at the hinges on the back.

BTW, I ordered a mess of large high-quality rubber bands (¾" wide) to seal the horn to metal tube interface and make it air-tight. Fits nicely. I could mail these to other members if they are interested and want to try this. $2.50 by paypal gets you 2 rubber bands in the mail (US only).

[AudioFeline]

An article from the "Popular Science Monthly" magazine, pp.26-27, Sept. 1922.
It's a "new" (for 1922) phonograph design which uses "resonating wooden rods".

https://books.google.com.au/books?id=6C ... &q&f=false

[Daithi]

An article from the "Popular Science Monthly" magazine, pp.26-27, Sept. 1922.
It's a "new" (for 1922) phonograph design which uses "resonating wooden rods".

https://books.google.com.au/books?id=6C ... &q&f=false

Wow, I'd love to hear and see one of those. I don't suppose any still exist?