[sdiy] Lafayette RK 142V Solid state Reel to Reel muckings about

[Gordonjcp]

On Wed, Dec 16, 2015 at 01:33:37PM -0800, Jason Dickson wrote:
> So ive had a working Lafayette RK 142V solid state reel to reel tape
> recorder/playback deal for a while that i never use, and now ive decided to
> turn it into a tape echo type thing, but with some twists. I want to
> incorperate a function generator, and a method to controll the motor speed
> via CV so that i can use it as a tape based additive/subtractive
> synthesizer, by introducing waveforms into the tape loop and then
> adding/subtracting harmonics and such via introducing other wave forms in
> various phases and amplitudes vs. the beginning input waveforms, and
> controlling playback speed. Anyone have experience with this R2R? Ive
> ordered a repair manual for it, as i couldnt find any details about it
> online. Pleanty of information abounds about its older counterpartk, the RK
> 142(tube based) R2R.

Depends on the type of motor.  If it's an AC-powered induction motor you'll need to go down the route of a Motor Drive Amplifier, which would be a Fun Project.  If it's a DC motor you could probably just use a MOSFET and PWM it to control the speed.

You won't be able to change speed rapidly due to the mechanical inertia of the system - there will be a seriously chunky flywheel on the capstan to prevent rapid changes of speed!  A few Hz getting you into flutter territory is about as far as you'll get.

If you're using a loop with a spring-loaded tension arm you might be able to have some kind of actuator on that to wobble the tape about.

-- 
Gordonjc