LDA Quartz Turntable Power Supply MKII

For use powering a turntable both the purity AND accuracy of the mains supply is of paramount importance, so LDA have designed a new Quartz Reference Power Generator, a source of 50Hz power that is digitally generated with the goal of providing an exact 50Hz sine wave of high frequency stability and low distortion..

Low distortion is vital when powering any item of audio equipment, but the motor in a turntable such as those used in the Garrard, Thorens TD124 and Lenco idler drive deck seem to be particularly sensitive to noise and harmonics in the supply. The effect of those extra parts to the AC supply are often only noticed when they are removed, and it has been our experience when testing the LDA Quartz Regenerator, that the effect of adding it to a system using this sort of turntable can only be described as a shock. The reason for this improvement is simple to understand once its demonstrated. The motor is designed to convert a 50 Hz Sine Wave into rotation. Any additions to that signal (both noise and distortion) will also be converted into mechanical energy by the motor, but unlike the smooth rotation to turn the platter, the extra signal will be injected into the mechanical system, eventually ending up at the record/cartridge interface and so into your music. The design of the turntable has been optimized to remove any 50Hz based signal and prevent it from getting to the cartridge, but the higher frequency distortion and noise will bypass any mechanical prevention methods and do its damage. The only way to prevent this, is to not inject the additional signal into the turntable at its source, the motor. The LDA Quartz Regenerator does this by generating an AC power supply that is orders of magnitude quieter than is available from your household supply.

The thing that distinguishes the motor used in these sorts of turntables is they are much larger and more powerful than those used in many modern belt drive turntables. To make the best use of these motors, they need to have a source of power that can meet the requirements of the motor without running out of power. There have been mains regenerators in the past that have provided low distortion supplies, but they have been aimed at small motors. The LDA Quartz Regenerator is specifically designed to feed the higher power that Garrard and Lenco turntables need.

The other requirement of any turntable motor is that it rotates at the correct speed. The power companies guarantee the frequency of the mains supply will remain ON AVERAGE at 50Hz, over the period of one day. There are several website, where you can check the actual frequency of the mains from second to second.

The simple fact is that the frequency stability of the mains supply is not of the accuracy required to power your turntable. The 50Hz signal in the LDA Quartz Regenerator is digitally derived from a 16Mhz quartz crystal with a frequency stability of better than 30 ppm, (that’s parts per million). That source clock is divided down to provide a 50Hz signal that is accurate, and constant to 0.003%.

The wall mains supply will vary from moment to moment by up to 2%. In this case the numbers do speak for themselves.

You may be asking, “why, if the frequency is this variable, don’t I see it on the strobe?”. The simple answer is that the strobe is driven by the same 50Hz supply as the turntable, so if the wall mains becomes 51Hz, the turntable rotates 2% faster, and the strobe flashes 2% faster, so you are unaware of the change. The only way to see this is to use a strobe derived by its own stable quartz clock reference, then you will see what the turntable strobe is hiding from you.

SPECIFICATIONS

• Powers Garrard – Thorens – Lenco - Commonwealth 12D

• Exact 50Hz sine wave

• Low distortion

• Built in speed controller

• Quartz locked

• 50W Power Supply

• Variable Frequency Output

• Switchable 110v/60Hz and 220v/50Hz output by bottom dip switches

• Rear toggle switch speed lock function