PAPER HORN "BALMAIN"

[emgcr]

Here are enlargements showing the Hornby track and wheels to allow low friction longitudinal motion. I only have photos of this wonderful confection I am afraid and have never actually seen it "in the flesh" so cannot comment on the performance. Sadly, I cannot now remember who is the very capable owner/constructor.

Regarding "swingers", the photos show the forks/cradle pivoted on the carriage directly under the vertical centre-line of the horn which is a neat (part) solution to that potential problem. There is also built-in lateral restraint and compliance (other part) at the needle end along the rail. It would be important to position the forks/bearings correctly to result in an acceptable needle pressure. Tracking is completely perfect if the needle is arranged to arrive at the motor spindle centre.

[Henry]

Can you tell me the method that was used to allow the horn to slide along the track, please?

Very clever use of flanged wheels running on model railroad track! I can't tell gauge of track, whether HO, OO, S, or O, but I presume that it's whatever is more common in the UK. It looks like manufactured track sections, readily available at hobby shops. One could use freight or passenger car trucks for the carriages. These have very low rolling resistance (though perhaps not as low as a mercury bath!).

[Curt A]

Ball bearing drawer slides might work well instead of railroad tracks... That is a fascinating machine, thanks for posting pics of it... Another project???
Another idea is linear slides that are used on CNC machines - roller bearing pillow block gliding on a round rail...

[Curt A]

For those of us who can't make a papier mache long horn, I think a flowered cylinder horn could be adapted and would look cool...

[emgcr]

Can you tell me the method that was used to allow the horn to slide along the track, please?

I can't tell gauge of track, whether HO, OO, S, or O, but I presume that it's whatever is more common in the UK.

Hornby 00 I think.

[emgcr]

Ball bearing drawer slides might work well instead of railroad tracks... That is a fascinating machine, thanks for posting pics of it... Another project???
Another idea is linear slides that are used on CNC machines - roller bearing pillow block gliding on a round rail...

Linear ball bearing sets are a brilliant and very clever invention---they certainly would work most effectively in this application.

[Inigo]

I wonder how many grams of force are required for sliding this enormous inertia-mass, exerted by the grooves on the needle point for lateral tracking across the record... The poor soundbox at the needlebar joint to the diaphragm would have to work out this resistance. It is the minimum rolling resistance force of the complete train which must be reduced to a minimum for the lateral tracking force exerted by the groove to be minimal. On the other hand, such an enormous mass is the perfect reaction needed for transmitting the maximum vibration to the diaphragm. It seems interesting to try different flexibility rubber connectors between the soundbox neck and the horn. A too flexible connector would ruin the arrangement, for it would be the escape path for the vibration energy transmitted by the needlebar fulcrum to the soundbox body. A too stiff connector would maximize the energy transmitted to the diaphragm, but at the cost of unwanted vibrations transmitted by the sb body to the horn. Surely the optimum will be in-between... Some value related to the diaphragm dynamic stiffness at the needlebar joint. A curious problem. The usual connector for the HMV tonearms could not be the optimum, as it is (arguably) tuned for a very different reactive mass-inertia... Wow! The famous Maxwell & Harrison equations of the orthophonic equivalent impedance circuit are thoroughly altered in this arrangement. Has anyone worked this out?

[Curt A]

How about fashioning a horn out of mylar, instead of paper, to reduce the weight of the horn. Modern electronic speaker cones can be either paper or mylar, so the performance issues are eliminated. Maybe a lightweight cone/horn shaped exo-skeleton with a mylar lining... This might reduce the resistance enough to work well... Just thinking...

[Curt A]

I think I have this figured out - use a morning glory cylinder horn firmly mounted to a linear rail and instead of the reproducer mounted directly to the horn, connect a length of flexible tubing to the end of the horn and insert the reproducer into that, similar to the flexible connection on an Edison Cygnet horn... That way, the reproducer has the ability to move without having a rigid connection that might cause tracking issues... The horn can glide smoothly on the linear rail without much resistance similar to the Pathé cylinder machine contraption that uses a flexible rubber reproducer connection.

[emgcr]

Your idea is good. Here is an original Balmain/Wilson type horn connector although the materials might be a trifle solid by now ! We should thank Chunny for the photos which he posted many years ago on another forum and I hope will not object to seeing here ?