Straight Arm Mod

From skratchtek
Jump to: navigation, search

Focus invented the first Technics straight arm mod :

Index.jpg

The formula for calculating the ideal length of an underhung straight tonearm is as follows :

Armformula.png

Where :

L = The length the tonearm needs to be, from the pivot point to the needle

D = The distance from the tonearm pivot to the spindle

C = The record radius constant, (3.04 for 10 inch records, 3.18 for 12 inch records, see the Radiotron handbook)


C can be found by measuring the outside and inside radius of a typical record's grooves and plugging the values into this formula :


C = (R12 * R22) / (R12 + R22)


Where :

R1 = Outside radius of record groove

R2 = Inside radius of record groove

More information can be found in the Radiotron Designers Handbook, page 765 : [1]