Operation – THORENS TD 550 User Manual
Page 37

Operation
By pressing the
Power button (1) the record player is
switched on or off. If switched on the Thorens-logo in the 
centre of the front panel will be illuminated as well as one 
of the speed indicator LEDs. Select the desired speed by 
means of the 
speed selector buttons (4+5) and press
the
Start button (2) in order to start the motor. The Start
LED will then be lit. When the motor is running you may 
change between speed without having to stop the mo-
tor beforehand. If the 
Start button (2) is pressed once
again the motor will stop and the respective LED goes off. 
If switched on the next time the previously selected speed 
will be indicated.
HINT: the TD 550 is equipped with an intelligent start-up 
control which within the first four seconds makes the mo-
tor initially running at half the selected speed and thus is 
reaching the rated speed more quickly than without this 
control. This applies also to the rated speed of 45 rpm.
Both 33 and 45 rpm have been factory-calibrated by 
means of a very precise 300-Hz stroboscope disk. The 
built-in motor control circuitry is capable to maintain 
precise rpm without any deviations for many years to 
come. In the event that you would like to fine-adjust 
the speeds yourself you can do this via the 
potenti-
ometers (11+13) provided at the rear panel and by 
using a fine, bladed screwdriver (trimmer). However we 
recommend to keep the factory settings if you don‘t 
have access to a precise stroboscope disk and lamp 
in order to control the adjustments.
An explanation of operational elements and connec-
tions at the TD 550 is given in Figure 1 on page 25 of 
this manual.
37
