Here's something you don't see everyday... (ROK content!)

[monkboughtlunch]

The Universal motor in your K33 states on the side it is 1600 RPM. The 11% slip below true synchronous speed means it is an asynchronous induction motor. To offset the slippage, the capstan on a Universal motor will be larger in diameter than a capstan on a synchronous motor.

The Universal s most likely a 4 pole induction motor so you can use magnetic carts without fear of hum that would occur in a 2 pole motor.

ROK began using Papst hysteresis motors (your K33 does not have one) in the late 1950s on higher end models such as the B12, and your K33 likely dates from the early 1960s.

Therefore, this K33 as configured is a budget model as it uses a lower tier induction motor. Note that it may be normal for the Universal motor to not reach 1600 RPM until after the motor has warmed up. Slippage and warm up time to hit full speed is normal in a budget induction motor design of this type.

You might be able to transplant a Papst from an eBay or Craigslist parts unit for enhanced performance.

You will want to replace the motor mounts with new Lord type available from Esoteric for damping.

If you use the Universal motor, you may need to rebuild/relube it to expunge the old lubrication which may be gummy after nearly 60 years of non-use.

 

[AdamAnt316]

Yet again, thanks for the replies! Still find it a bit odd that these turntables were offered with an induction motor in the first place; guessing it was ROK's way of getting rid of old stock once the hysteresis models were introduced (there doesn't seem to have been a plain N-33 with an induction motor). When they did introduce the K-33H, it cost $10 more than the plain model, which was sold alongside it for at least one year for the old price. Wouldn't surprise me if this unit is either unsold stock, or if the buyer decided to opt for an H model once they were released, and decided not to bother installing this one (or kept it around as a spare).
-Adam