TCA561 Motor Contr. Unit - Datasheet or internal Circuit wanted

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There is this technical information on it, if you wanted to make your own!

Wow - thank you very much. Such website starting is completly new for me (sorry, I am not computer and online expert).
How it is possible in general, to find download-aeras about "google" from websites,
that starts with "ftp" instead "http://www" ??
Perhaps about this way is also to find various data sheets from other stuff - I want to have in the moment various data sheets for optical stuff in cd player -
1) Sharp LTOH30P/LTOH30PA/LT0H30PA/LT0H30P
2) Sony KSS-Series
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TCA 561 TCA561 Motor Control Unit, FASELEC (Philips, now NXP) made for Studer/REVOX

before the website is deleted I think, it is better to save the datasheet of the TCA561 here as pdf documents. I have an old IC handbook from data-becker, where a lot of analog ICs listed with internal circuits/block diagrams. Maybe there are one or more good known and good to find IC type of motor control units, which are only a little bit different than the TCA 561. This means, that only a small amount of modifications should be necessary. Because the TCA561 is a "hard to find" part, this could be helpful for several users of REVOX and Studer tapes.


  • TCA561 block diagram.pdf
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  • TCA561 intern. schem. diagram.pdf
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  • TCA561 resistor values.pdf
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  • TCA561 pin description.pdf
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It is an analog multiplier IC with extras


TCA561 is used in many Studer/Revox tape recorders as motor controller circuit. Eg. in A700 it is used both for capstan motor control and spooling motor control. It is used to multiply two signals, desired motor speed/force and rectified AC voltage. The result is fed to the transistor which moderates the current through AC motor winding. This way, a nice rotating (and flutter free) magnetic field is produced.

For capstan motor, this is enough.

For spooling motors, however, estra features are used. TCA561 also has a selector for one of the analog inputs. In play mode, left tension arm controls the left motor and vice versa. However, in fast winding, left arm controls the right motor and vice versa. This is accomplished selection pins without extra selectors. Other control pins are used to enable and disable functionality.

TCA561 can be replaced with a circuit where multiplication is made with a matched FET pair. FET is used as an adjustable resistor in opamp feedback loop. Later A700 has this FET circuit instead of TCA561. You can check yourself in the circuit diagram at: . Just compare Tape Transport Ctrl circuits of earlier and later models as well as Capstan control circuits.

If this needed to be implemented now, I would think three ways:

  1. FET circuit of later A700 models.
  2. Using opamps and AD633.
  3. Atmel AVR: A/D converters as inputs and output with high speed PCM.
One could also copy Studer A810 spooling motor circuit which uses PCM control directly to the motors. But I think this would be an overkill.
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.