Norma Reproducer - what is it?

[Marco Gilardetti]

I got an automatic alert that a "Norma Reproducer" is for sale...

https://www.ebay.it/itm/401557427081

Does anyone know what the bar is for, how does the gizmo operate, and to what effect? I really couldn't figure out...

[barnettrp21122]

Interesting!
Maybe a counter-balance to lighten the soundbox pressure on the record? Looks cumbersome!

[MicaMonster]

I found this.....the physics of it don’t quite check out. Seems to me that a tremendous amount if pressure (preload) is being placed on the diaphragm, and in the wrong way. The only thing this British reproducer DOESN’T Do is leak oil in the driveway.

....yet

[epigramophone]

Same seller. Same item?

https://www.ebay.co.uk/itm/VINTAGE-NORM ... 3157683733

[Orchorsol]

I'v heard they sound remarkably good, but I can't fathom how or why, and they must surely cause more record wear...

[CarlosV]

I have one of these, it indeed works, significantly increasing the volume of the reproduction. It is quite effective when used in portables. On the negative side, it also increases the pressure on the groove and consequently the wear on the record, so I used it a couple of times and stored it away under gizmos and curiosities.

[Marco Gilardetti]

Looks like it is based on a combination effect of a different pivot point that can not only rotate over the join but also swing over the horizontal plane (makes sense) plus mass added to the tip (makes sense again, although I have never found so far a scientific explanation about why a mass added to the tip increases the volume, and although I thought about it since I first saw those needles with added masses, I couldn't figure out by myself).

What I really fail to understand is why the mass is applied on the left far side with that long weird spring bar. I would possibly figure out by looking at the gizmo at work, but it looks nonsense just by looking at pictures.

In any case, as Carlos noted, this is the exact opposite of a "counter-balance to lighten the soundbox pressure", and people already concerned about the average wheight of standard soundboxes should definitely avoid it!

[estott]

I can only guess it was aimed at people who were playing popular hits & would be discarding records before they wore out.

[jboger]

There's an old saying that goes, it's better to keep your mouth shut and have people think you a fool than open it and remove all doubt. So disregarding that, let me assume that there really is a volume enhancement, as someone observed. We all know that the needle tracks the groove and transmits that vibration to the diaphragm via the needle bar. The volume out of the soundbox depends in part on how much the needle bar pushes and pulls on the diaphragm: a large displacement from the "at rest" (equilibrium) position leads to louder volume than a small displacement. This is shown in picture 2 in the advertisement without the Norma device. The horizontal line at the top of the triangle is proportional to the amount of displacement induced by a stationary needle holder with a fixed pivot point. Picture 3, on the other hand, shows the total displacement induced by the floating needle holder. The picture shows two triangles that result from the displacement of the needle holder, the sum of which (neglecting overlap) is proportional to the displacement of the diaphragm about its equilibrium position. So why the weight? My guess is that it's what drives the floating needle holder to move by taking advantage of the full width of the groove at any particular point in the record. Depending on the shape of the groove at a particularly point, the weight causes the needle (and thereby the needle holder) to tip to one side of the groove, which motion is transmitted to the needle bar causing a larger displacement in the diaphragm and enhanced volume than without this device. Just to be (hopefully) a little clearer, when I write "displacement", I mean the diaphragm is vibrating about a central, equilibrium position, sort of like a pendulum. A pendulum can have a wide swing or a short swing about the "at rest" position when the bob just hangs vertically. The more the diaphragm is displaced from its "at rest" position, the louder the volume out of the sound box. Anyway, someone can tell me I'm full of crap, at which point i shall be reminded of that old saying.