Motor


The original motor fitted to the earliest LP12 turntables was a 250 rpm AC synchronous two-phase motor. This type of motor speed is solely determined by the frequency of the mains supply. It is guaranteed to run 250 rpm at 50Hz or 300 rpm at 60Hz. When an early LP12, without a regenerative power supply such as a Vahalla or Lingo, is used on an unstable mains supply, fluctuations in speed stability will be apparent and will spoil the enjoyment of the music due to excessive wow and flutter (speed irregularities).


Premotec Motor


Premotec Motor

The Premotec (other manufacturers are also available) motor has been installed in LP12 turntables for years and they usually last a long time. A client recently said his motor was starting to be really noisy, although the speed was correct. A bit of oil and cleaning out the bottom of the motor, where the spring and stainless steel ball are located, is all that was required. The motor is now silent during operation.


Valhalla Power Supply

Valhalla Power Supply

The earliest LP12 turntables did not feature a power supply. It was a mere simple phase-shift network with torque reduction that fed the synchronous motor directly. In the early eighties a new, most sophisticated system was introduced and it was called the Valhalla. This was a mains operated system that rectified the incoming supply to a steady DC current and then via a crystal oscillator driven IC system regenerated a very steady 50Hz alternating current to drive the motor. This was a big leap in the performance of the LP12. The Valhalla was superseded by the Lingo in 1990.

Since then, a number of third-party power supplies were brought to the market both for the traditional AC synchronous motor systems and also DC motor systems. The Klimax uses an error-feedback DC motor system. It ensures that the platter rotates at a very steady speed with optical feedback to ensure that the speed is consistent at either 33.33 or 45 rpm.

The Valhalla power supply remains extremely popular and offers the advantage of filtering out fluctuations in the mains feed to the motor, ensuring a consistent speed. It is a very common upgrade. As with many power supplies, the capacitors will age, but they can be replaced. Recently a client brought an LP12 to us. The unit would run for a few minutes and then stop. The capacitors were replaced, and now the 41-year old turntable performs as if it were a new unit. The cost was miniscule.