TurntablePSU.comReviews and Technical Analysis
LongDog Audio PSU
Overview
The $1135 (£895) LongDog Audio PSU is a dual frequency supply that uses DDS to generate the 33/45 RPM sinewave signal. A front panel switch is used for changing between 33 and 45 RPM and a rotary switch for adjusting either frequency in 0.01Hz steps with a maximum range of ±3Hz.
The LDA PSU is powered by a 120 or 240 VAC input, and the PSU has one output to the turntable, the connector type is factory installed for compatibility with the mains supply in your country; the output is enabled when ever the front panel power switch is on. Like most of the other PSUs on the market, the LDA PSU uses 50/60Hz for 33 RPM and 67.5/81Hz for 45 RPM, so the turntable belt must be installed on the small spindle of the pulley (33 RPM). Two internal switches allow you to set the output voltage (115/230VAC) and the base output frqeuency (50/60Hz).
One front panel switch selects either 33/45 RPM and the other control changes the output frequency by 0.01Hz per step. The LED indicator will show red if the frequency is adjusted below the base frequency, green if the frequency is adjusted above the base frequency, yellow if set to the base frequency and flashes if the adjustment is turned past the limits (±3Hz). There is a lock switch on the back panel that disables the front panel speed adjustment; the LED indicator will also flash if the lock switch is enabled and the speed adjustment control is turned. There is a separate speed adjustment for each frequency (33/45 RPM), the offset is stored in non-volatile memory and is unaffected by removing power from the supply.
Specifications
Nominal Speeds............................33 and 45 RPM
Speed Stability..............................0.01% (100 PPM)
Distortion (Freq Generator).............0.25%
Distortion (115VAC output)..............0.65%
Pitch Control.................................0.01Hz ±3Hz max.
Output Power................................25W
Reduced Voltage...........................Not available
Input............................................115/230VAC IEC C14
Turntable Connection.....................Country dependent
Weight..........................................10 lbs.