motor rpm

[steve04]

Hello.

I am trying to vary the speed of a tape deck by varying the external supply (cord) voltage.

Does anyone have opinion.

Thanks.

Steve

[Tomi Engdahl]

Typically the tape decks are built using a regulated motor circuit.
There is typically some electronics inside the tape deck that keeps
the motor speed more or less constant.

Most probable you can't get any useful control range by varying the
external supply voltage. Maybe you get some variation in speed
and some other side-effects...

[Guest]

Thanks to Tomi for the opinion.

From published material, I have noted that there may be a rpm monitor circuit involved, that resets the speed if it varies from the preset value.

Steve