Re: [ARSCLIST] Playback of Durium Junior Records

[George Brock-Nannestad <pattac@xxxxxxxx>]

From: Patent Tactics, George Brock-Nannestad

Jack  Raymond wrote:

> What is meant by the "overhang" that has to be adjusted?

because

> Steven Smolian wrote:
>
> > In addition. you need a tone arm set up to pay the "label" area of
> > the record, which means the overhang has to be adjusted for this
> > purpose.


The "overhang" is a term described (though not used) by Percy
Wilson in articles in the Gramophone and extensively in the book
"Modern Gramophones and Electrical Reproducers" by himself and
George Webb. The book (1929) is quite expensive in the original
and it has been re-issued in an equally expensive facsimile.
However, it is essential reading for the person interested in
mechanical records.

It refers to the desire that the side of the pickup (actually the
cantilever or stylus bar) cartridge has to be tangential to the groove
it is tracking. With a pivoted arm (as opposed to a tangential
tracking arm) a better compromise can be obtained for a short
tonearm over the record surface by having an angle between the
direction of the cantilever and the line joining the stylus tip and the
pivot of the tonearm. The compromise means that over a 12 inch
record, there are two places where the cantilever is truly tangential,
rather than one only. However, the absolute timing of the record
suffers a very little, and some heavily modulated records will also
suffer velocity modulation (a form of distortion).

So, by turning the cartridge in the headshell as well as pushing it
backwards and forwards it will be possible to play records as small
as a normal LP label. If you do not have a "protractor" aim at
obtaining tracking so that the cartridge or cantilever is
perpendicular to the line connecting the centre of the turntable and
the place the tip of the stylus touches the record halfway through
the record. The "overhang" would mean that you actually move the
cartridge slightly forward of this. If you use a spherical tip the
adjustment is not critical. Note that some tonearms will not at all
travel over the label area of an LP - you may have to remove some
limiting hardware below the plinth.

Hoping to have inspired some activity,

kind regards,

George