You can buy replacement strings directly from Auris:

for wich Lyre?

The First Tuning

In order for the lyre to hold its pitch as long as possible after tuning, it is important that the very first tuning is done in the following manner: Do never move the tuning wrench when the string is not sounding! First tune all of the strings to their right pitch. Then press down relatively hard with your finger in the middle of each string. It should flex 1/4 inch / 7 – 8 mm. The tones will now have become lower because the strings stretch and the lyre body bends slightly under the string tension. Now, repeat the procedure until the strings withstands the pressure of your finger without losing their pitch.

Changing The Strings

The strings are changed either when they no longer hold a clear tone or when they have broken. When you change a broken string you must not forget to unscrew the tuning pin as many turns as it has been tightened. This will be about three or three and a half turns. The tuning pins have left hand threads which means that they screw out clockwise, and in counter-clockwise. When the new string is placed on the lyre, it is attached to the pin and cut as shown in pict.4 and wound up as in pict.5